Go Bindings for the lua C API
=========================

![Build Status](https://github.com/aarzilli/golua/actions/workflows/build.yml/badge.svg)

Simplest way to install:

	# go get github.com/aarzilli/golua/lua

You can then try to run the examples:

	$ cd golua/_example/
	$ go run basic.go
	$ go run alloc.go
	$ go run panic.go
	$ go run userdata.go

This library is configured using build tags. By default it will look for a library (or "shared object") called:

* lua5.1 on Linux and macOS
* lua on Windows
* lua-5.1 on FreeBSD

If this doesn't work `-tags luadash5.1` can be used to force `lua-5.1`, and `-tags llua` can be used to force `lua`.

If you want to statically link to liblua.a you can do that with `-tags luaa`. Luajit can also be used by
specifying `-tags luajit`.

The library uses lua5.1 by default but also supports lua5.2 by specifying `-tags lua52`, lua5.3 by
specifying `-tags lua53`, and lua5.4 by specifying `-tags lua54`. If the library installed on your system has a dash, for example it is called `liblua-5.4` use the `lluadash` tag: `go build -tags lua54,lluadash ...`.

QUICK START
---------------------

Create a new Virtual Machine with:

```go
L := lua.NewState()
L.OpenLibs()
defer L.Close()
```

Lua's Virtual Machine is stack based, you can call lua functions like this:

```go
// push "print" function on the stack
L.GetGlobal("print")
// push the string "Hello World!" on the stack
L.PushString("Hello World!")
// call print with one argument, expecting no results
L.Call(1, 0)
```

Of course this isn't very useful, more useful is executing lua code from a file or from a string:

```go
// executes a string of lua code
err := L.DoString("...")
// executes a file
err = L.DoFile(filename)
```

You will also probably want to publish go functions to the virtual machine, you can do it by:

```go
func adder(L *lua.State) int {
	a := L.ToInteger(1)
	b := L.ToInteger(2)
	L.PushInteger(a + b)
	return 1 // number of return values
}

func main() {
	L := lua.NewState()
	defer L.Close()
	L.OpenLibs()

	L.Register("adder", adder)
	L.DoString("print(adder(2, 2))")
}
```

ON ERROR HANDLING
---------------------

Lua's exceptions are incompatible with Go, golua works around this incompatibility by setting up protected execution environments in `lua.State.DoString`, `lua.State.DoFile`  and lua.State.Call and turning every exception into a Go panic.

This means that:

1. In general you can't do any exception handling from Lua, `pcall` and `xpcall` are renamed to `unsafe_pcall` and `unsafe_xpcall`. They are only safe to be called from Lua code that never calls back to Go. Use at your own risk.

2. The call to lua.State.Error, present in previous versions of this library, has been removed as it is nonsensical

3. Method calls on a newly created `lua.State` happen in an unprotected environment, if Lua throws an exception as a result your program will be terminated. If this is undesirable perform your initialization like this:

```go
func LuaStateInit(L *lua.State) int {
	… initialization goes here…
	return 0
}

…
L.PushGoFunction(LuaStateInit)
err := L.Call(0, 0)
…
```

ON THREADS AND COROUTINES
---------------------

'lua.State' is not thread safe, but the library itself is. Lua's coroutines exist but (to my knowledge) have never been tested and are likely to encounter the same problems that errors have, use at your own peril.

ODDS AND ENDS
---------------------

* If you want to build against lua5.2, lua5.3, or lua5.4 use the build tags lua52, lua53, or lua54 respectively.
* Compiling from source yields only a static link library (liblua.a), you can either produce the dynamic link library on your own or use the `luaa` build tag.

LUAJIT
---------------------

To link with [luajit-2.0.x](http://luajit.org/luajit.html), you can use CGO_CFLAGS and CGO_LDFLAGS environment variables

```
$ CGO_CFLAGS=`pkg-config luajit --cflags`
$ CGO_LDFLAGS=`pkg-config luajit --libs-only-L`
$ go get -f -u -tags luajit github.com/aarzilli/golua/lua
```

CONTRIBUTORS
---------------------

* Adam Fitzgerald (original author)
* Alessandro Arzilli
* Steve Donovan
* Harley Laue
* James Nurmi
* Ruitao
* Xushiwei
* Isaint
* hsinhoyeh
* Viktor Palmkvist
* HongZhen Peng
* Admin36
* Pierre Neidhardt (@Ambrevar)
* HuangWei (@huangwei1024)
* Adam Saponara
* [Tim van Osch](https://github.com/TimVosch)

SEE ALSO
---------------------

- [Luar](https://github.com/stevedonovan/luar/) is a reflection layer on top of golua API providing a simplified way to publish go functions to a Lua VM.
- [lunatico](https://github.com/fiatjaf/lunatico) is a reflection layer that allows you to push and read Go values to a Lua VM without understanding the Lua stack.
- [Golua unicode](https://github.com/Ambrevar/golua) is an extension library that adds unicode support to golua and replaces lua regular expressions with re2.

Licensing
-------------
GoLua is released under the MIT license.
Please see the LICENSE file for more information.

Lua is Copyright (c) Lua.org, PUC-Rio.  All rights reserved.


golua

# Anko

[![GoDoc Reference](https://godoc.org/github.com/mattn/anko/vm?status.svg)](http://godoc.org/github.com/mattn/anko/vm)
[![CI](https://github.com/mattn/anko/actions/workflows/ci.yml/badge.svg)](https://github.com/mattn/anko/actions/workflows/ci.yml)
[![Financial Contributors on Open Collective](https://opencollective.com/mattn-anko/all/badge.svg?label=financial+contributors)](https://opencollective.com/mattn-anko) [![Coverage](https://codecov.io/gh/mattn/anko/branch/master/graph/badge.svg)](https://codecov.io/gh/mattn/anko)
[![Go Report Card](https://goreportcard.com/badge/github.com/mattn/anko)](https://goreportcard.com/report/github.com/mattn/anko)

Anko is a scriptable interpreter written in Go.

![](https://raw.githubusercontent.com/mattn/anko/master/anko.png)

(Picture licensed under CC BY-SA 3.0, photo by Ocdp)


## Usage Example - Embedded

```go
package main

import (
	"fmt"
	"log"

	"github.com/mattn/anko/env"
	"github.com/mattn/anko/vm"
)

func main() {
	e := env.NewEnv()

	err := e.Define("println", fmt.Println)
	if err != nil {
		log.Fatalf("Define error: %v\n", err)
	}

	script := `
println("Hello World :)")
`

	_, err = vm.Execute(e, nil, script)
	if err != nil {
		log.Fatalf("Execute error: %v\n", err)
	}

	// output: Hello World :)
}
```

More examples are located in the GoDoc:

https://godoc.org/github.com/mattn/anko/vm


## Usage Example - Command Line

### Building
```
go get github.com/mattn/anko
go install github.com/mattn/anko
```

### Running an Anko script file named script.ank
```
./anko script.ank
```

## Anko Script Quick Start
```
// declare variables
x = 1
y = x + 1

// print using outside the script defined println function
println(x + y) // 3

// if else statement
if x < 1 || y < 1 {
	println(x)
} else if x < 1 && y < 1 {
	println(y)
} else {
	println(x + y)
}

// slice
a = []interface{1, 2, 3}
println(a) // [1 2 3]
println(a[0]) // 1

// map
a = map[interface]interface{"x": 1}
println(a) // map[x:1]
a.b = 2
a["c"] = 3
println(a["b"]) // 2
println(a.c) // 3

// struct
a = make(struct {
	A int64,
	B float64
})
a.A = 4
a.B = 5.5
println(a.A) // 4
println(a.B) // 5.5

// function
func a (x) {
	println(x + 1)
}
a(5) // 6
```


## Please note that the master branch is not stable

The master branch language and API may change at any time.

To mitigate breaking changes, please use tagged branches. New tagged branches will be created for breaking changes.


## Author

Yasuhiro Matsumoto (a.k.a mattn)

## Contributors

### Code Contributors

This project exists thanks to all the people who contribute. [[Contribute](CONTRIBUTING.md)].
<a href="https://github.com/mattn/anko/graphs/contributors"><img src="https://opencollective.com/mattn-anko/contributors.svg?width=890&button=false" /></a>

### Financial Contributors

Become a financial contributor and help us sustain our community. [[Contribute](https://opencollective.com/mattn-anko/contribute)]

#### Individuals

<a href="https://opencollective.com/mattn-anko"><img src="https://opencollective.com/mattn-anko/individuals.svg?width=890"></a>

#### Organizations

Support this project with your organization. Your logo will show up here with a link to your website. [[Contribute](https://opencollective.com/mattn-anko/contribute)]

<a href="https://opencollective.com/mattn-anko/organization/0/website"><img src="https://opencollective.com/mattn-anko/organization/0/avatar.svg"></a>
<a href="https://opencollective.com/mattn-anko/organization/1/website"><img src="https://opencollective.com/mattn-anko/organization/1/avatar.svg"></a>
<a href="https://opencollective.com/mattn-anko/organization/2/website"><img src="https://opencollective.com/mattn-anko/organization/2/avatar.svg"></a>
<a href="https://opencollective.com/mattn-anko/organization/3/website"><img src="https://opencollective.com/mattn-anko/organization/3/avatar.svg"></a>
<a href="https://opencollective.com/mattn-anko/organization/4/website"><img src="https://opencollective.com/mattn-anko/organization/4/avatar.svg"></a>
<a href="https://opencollective.com/mattn-anko/organization/5/website"><img src="https://opencollective.com/mattn-anko/organization/5/avatar.svg"></a>
<a href="https://opencollective.com/mattn-anko/organization/6/website"><img src="https://opencollective.com/mattn-anko/organization/6/avatar.svg"></a>
<a href="https://opencollective.com/mattn-anko/organization/7/website"><img src="https://opencollective.com/mattn-anko/organization/7/avatar.svg"></a>
<a href="https://opencollective.com/mattn-anko/organization/8/website"><img src="https://opencollective.com/mattn-anko/organization/8/avatar.svg"></a>
<a href="https://opencollective.com/mattn-anko/organization/9/website"><img src="https://opencollective.com/mattn-anko/organization/9/avatar.svg"></a>


anko

Go to Lua binding library, based on [gopher-lua](https://github.com/yuin/gopher-lua)

# Binder
High level go to Lua binder. Write less, do more.

[![Travis](https://img.shields.io/travis/alexeyco/binder.svg)](https://travis-ci.org/alexeyco/binder)
[![Coverage Status](https://coveralls.io/repos/github/alexeyco/binder/badge.svg?branch=master)](https://coveralls.io/github/alexeyco/binder?branch=master)
[![Go Report Card](https://goreportcard.com/badge/github.com/alexeyco/binder)](https://goreportcard.com/report/github.com/alexeyco/binder)&nbsp;[![GoDoc](https://godoc.org/github.com/alexeyco/binder?status.svg)](https://godoc.org/github.com/alexeyco/binder)
[![license](https://img.shields.io/github/license/alexeyco/binder.svg)](https://github.com/alexeyco/binder)
[![binder](https://img.shields.io/badge/awesome-go-red.svg)](https://github.com/avelino/awesome-go#embeddable-scripting-languages)

Package binder allows to easily bind to Lua. Based on [gopher-lua](https://github.com/yuin/gopher-lua).

*Write less, do more!*

1. [Killer-feature](#killer-feature)
1. [Installation](#installation)
1. [Examples](#examples)
    1. [Functions](#functions)
    1. [Modules](#modules)
    1. [Tables](#tables)
    1. [Options](#options)
    1. [Killer-featured errors](#killer-featured-errors)
1. [License](#license)

## Killer-feature

You can display detailed information about the error and get something like this:

![Error](https://raw.githubusercontent.com/alexeyco/binder/master/Error.png)

See [_example/04-highlight-errors](https://github.com/alexeyco/binder/tree/master/_example/04-highlight-errors). And [read more](#killer-featured-errors) about it.

## Installation
```
$ go get -u github.com/alexeyco/binder
```
To run unit tests:
```
$ cd $GOPATH/src/github.com/alexeyco/binder
$ go test -cover
```
To see why you need to bind go to lua (need few minutes):
```
$ cd $GOPATH/src/github.com/alexeyco/binder
$ go test -bench=.
```

## Examples

### Functions
```go
package main

import (
	"errors"
	"log"

	"github.com/alexeyco/binder"
)

func main() {
	b := binder.New(binder.Options{
		SkipOpenLibs: true,
	})

	b.Func("log", func(c *binder.Context) error {
		t := c.Top()
		if t == 0 {
			return errors.New("need arguments")
		}

		l := []interface{}{}

		for i := 1; i <= t; i++ {
			l = append(l, c.Arg(i).Any())
		}

		log.Println(l...)
		return nil
	})

	if err := b.DoString(`
		log('This', 'is', 'Lua')
	`); err != nil {
		log.Fatalln(err)
	}
}
```

### Modules
```go
package main

import (
	"errors"
	"log"

	"github.com/alexeyco/binder"
)

func main() {
	b := binder.New()

	m := b.Module("reverse")
	m.Func("string", func(c *binder.Context) error {
		if c.Top() == 0 {
			return errors.New("need arguments")
		}

		s := c.Arg(1).String()

		runes := []rune(s)
		for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
			runes[i], runes[j] = runes[j], runes[i]
		}

		c.Push().String(string(runes))
		return nil
	})

	if err := b.DoString(`
		local r = require('reverse')

		print(r.string('ABCDEFGHIJKLMNOPQRSTUFVWXYZ'))
	`); err != nil {
		log.Fatalln(err)
	}
}

```
### Tables
```go
package main

import (
	"errors"
	"log"

	"github.com/alexeyco/binder"
)

type Person struct {
	Name string
}

func main() {
	b := binder.New()

	t := b.Table("person")
	t.Static("new", func(c *binder.Context) error {
		if c.Top() == 0 {
			return errors.New("need arguments")
		}
		n := c.Arg(1).String()

		c.Push().Data(&Person{n}, "person")
		return nil
	})

	t.Dynamic("name", func(c *binder.Context) error {
		p, ok := c.Arg(1).Data().(*Person)
		if !ok {
			return errors.New("person expected")
		}

		if c.Top() == 1 {
			c.Push().String(p.Name)
		} else {
			p.Name = c.Arg(2).String()
		}

		return nil
	})

	if err := b.DoString(`
		local p = person.new('Steeve')
		print(p:name())

		p:name('Alice')
		print(p:name())
	`); err != nil {
		log.Fatalln(err)
	}
}
```

### Options
```go
// Options binder options object
type Options struct {
	// CallStackSize is call stack size
	CallStackSize int
	// RegistrySize is data stack size
	RegistrySize int
	// SkipOpenLibs controls whether or not libraries are opened by default
	SkipOpenLibs bool
	// IncludeGoStackTrace tells whether a Go stacktrace should be included in a Lua stacktrace when panics occur.
	IncludeGoStackTrace bool
}
```
Read [more](https://github.com/yuin/gopher-lua#miscellaneous-luanewstate-options).

For example:
```go
b := binder.New(binder.Options{
	SkipOpenLibs: true,
})
```

### Killer-featured errors

```go
package main

import (
	"errors"
	"log"
	"os"

	"github.com/alexeyco/binder"
)

type Person struct {
	Name string
}

func main() {
	b := binder.New()
	
	// ...

	if err := b.DoString(`-- some string`); err != nil {
		switch err.(type) {
		case *binder.Error:
			e := err.(*binder.Error)
			e.Print()

			os.Exit(0)
			break
		default:
			log.Fatalln(err)
		}
	}
}
```

Note: if `SkipOpenLibs` is `true`, not all open libs will be skipped in contrast to the basic logic of 
[gopher-lua](https://github.com/yuin/gopher-lua). If you set `SkipOpenLibs` to `true`, the following 
basic libraries will be loaded: all [basic functions](https://www.lua.org/manual/5.1/manual.html#5.1), 
[table](https://www.lua.org/manual/5.1/manual.html#5.5) and [package](https://www.lua.org/manual/5.1/manual.html#5.3).

## License
```
MIT License

Copyright (c) 2017 Alexey Popov

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
```


binder

Fast, portable, non-Turing complete expression evaluation with gradual typing

# Common Expression Language

[![Go Report Card](https://goreportcard.com/badge/github.com/google/cel-go)](https://goreportcard.com/report/github.com/google/cel-go)
[![GoDoc](https://godoc.org/github.com/google/cel-go?status.svg)][6]

The Common Expression Language (CEL) is a non-Turing complete language designed
for simplicity, speed, safety, and portability. CEL's C-like [syntax][1] looks
nearly identical to equivalent expressions in C++, Go, Java, and TypeScript.

```java
// Check whether a resource name starts with a group name.
resource.name.startsWith("/groups/" + auth.claims.group)
```

```go
// Determine whether the request is in the permitted time window.
request.time - resource.age < duration("24h")
```

```typescript
// Check whether all resource names in a list match a given filter.
auth.claims.email_verified && resources.all(r, r.startsWith(auth.claims.email))
```

A CEL "program" is a single expression. The examples have been tagged as
`java`, `go`, and `typescript` within the markdown to showcase the commonality
of the syntax.

CEL is ideal for lightweight expression evaluation when a fully sandboxed
scripting language is too resource intensive. To get started, try the
[Codelab](https://codelabs.developers.google.com/codelabs/cel-go/index.html).

---

* [Overview](#overview)
  * [Environment Setup](#environment-setup)
  * [Parse and Check](#parse-and-check)
  * [Macros](#macros)
  * [Evaluate](#evaluate)
  * [Errors](#Errors)
* [Examples](examples/README.md)
* [Install](#install)
* [Common Questions](#common-questions)
* [License](#license)

---

## Overview

Determine the variables and functions you want to provide to CEL. Parse and
check an expression to make sure it's valid. Then evaluate the output AST
against some input. Checking is optional, but strongly encouraged.

### Environment Setup

Let's expose `name` and  `group` variables to CEL using the `cel.Variable`
environment option:

```go
import "github.com/google/cel-go/cel"

env, err := cel.NewEnv(
    cel.Variable("name", cel.StringType),
    cel.Variable("group", cel.StringType),
)
```

That's it. The environment is ready to be used for parsing and type-checking.
CEL supports all the usual primitive types in addition to lists, maps, as well
as first-class support for JSON and Protocol Buffers.

### Parse and Check

The parsing phase indicates whether the expression is syntactically valid and
expands any macros present within the environment. Parsing and checking are
more computationally expensive than evaluation, and it is recommended that
expressions be parsed and checked ahead of time.

The parse and check phases are combined for convenience into the `Compile`
step:

```go
ast, issues := env.Compile(`name.startsWith("/groups/" + group)`)
if issues != nil && issues.Err() != nil {
    log.Fatalf("type-check error: %s", issues.Err())
}
prg, err := env.Program(ast)
if err != nil {
    log.Fatalf("program construction error: %s", err)
}
```

The `cel.Program` generated at the end of parse and check is stateless,
thread-safe, and cachable.

Type-checking is an optional, but strongly encouraged step that can reject some
semantically invalid expressions using static analysis. Additionally, the check
produces metadata which can improve function invocation performance and object
field selection at evaluation-time.

#### Macros

Macros are optional but enabled by default. Macros were introduced to
support optional CEL features that might not be desired in all use cases
without the syntactic burden and complexity such features might desire if
they were part of the core CEL syntax. Macros are expanded at parse time and
their expansions are type-checked at check time.

For example, when macros are enabled it is possible to support bounded
iteration / fold operators. The macros `all`, `exists`, `exists_one`, `filter`,
and `map` are particularly useful for evaluating a single predicate against
list and map values.

```javascript
// Ensure all tweets are less than 140 chars
tweets.all(t, t.size() <= 140)
```

The `has` macro is useful for unifying field presence testing logic across
protobuf types and dynamic (JSON-like) types.

```javascript
// Test whether the field is a non-default value if proto-based, or defined
// in the JSON case.
has(message.field)
```

Both cases traditionally require special syntax at the language level, but
these features are exposed via macros in CEL.

### Evaluate

Now, evaluate for fun and profit. The evaluation is thread-safe and side-effect
free. Many different inputs can be sent to the same `cel.Program` and if fields
are present in the input, but not referenced in the expression, they are
ignored.

```go
// The `out` var contains the output of a successful evaluation.
// The `details' var would contain intermediate evaluation state if enabled as
// a cel.ProgramOption. This can be useful for visualizing how the `out` value
// was arrive at.
out, details, err := prg.Eval(map[string]interface{}{
    "name": "/groups/acme.co/documents/secret-stuff",
    "group": "acme.co"})
fmt.Println(out) // 'true'
```

#### Partial State

What if `name` hadn't been supplied? CEL is designed for this case. In
distributed apps it is not uncommon to have edge caches and central services.
If possible, evaluation should happen at the edge, but it isn't always possible
to know the full state required for all values and functions present in the
CEL expression.

To improve the odds of successful evaluation with partial state, CEL uses
commutative logical operators `&&`, `||`. If an error or unknown value (not the
same thing) is encountered on the left-hand side, the right hand side is
evaluated also to determine the outcome. While it is possible to implement
evaluation with partial state without this feature, this method was chosen
because it aligns with the semantics of SQL evaluation and because it's more
robust to evaluation against dynamic data types such as JSON inputs.

In the following truth-table, the symbols `<x>` and `<y>` represent error or
unknown values, with the `?` indicating that the branch is not taken due to
short-circuiting. When the result is `<x, y>` this means that the both args
are possibly relevant to the result.

| Expression          | Result   |
|---------------------|----------|
| `false && ?`        | `false`  |
| `true && false`     | `false`  |
| `<x> && false`      | `false`  |
| `true && true`      | `true`   |
| `true && <x>`       | `<x>`    |
| `<x> && true`       | `<x>`    |
| `<x> && <y>`        | `<x, y>` |
| `true \|\| ?`       | `true`   |
| `false \|\| true`   | `true`   |
| `<x> \|\| true`     | `true`   |
| `false \|\| false`  | `false`  |
| `false \|\| <x>`    | `<x>`    |
| `<x> \|\| false`    | `<x>`    |
| `<x> \|\| <y>`      | `<x, y>` |

In the cases where unknowns are expected, `cel.EvalOptions(cel.OptTrackState)`
should be enabled. The `details` value returned by `Eval()` will contain the
intermediate evaluation values and can be provided to the `interpreter.Prune`
function to generate a residual expression. e.g.:

```cpp
// Residual when `name` omitted:
name.startsWith("/groups/acme.co")
```

This technique can be useful when there are variables that are expensive to
compute unless they are absolutely needed. This functionality will be the
focus of many future improvements, so keep an eye out for more goodness here!

### Errors

Parse and check errors have friendly error messages with pointers to where the
issues occur in source:

```sh
ERROR: <input>:1:40: undefined field 'undefined'
    | TestAllTypes{single_int32: 1, undefined: 2}
    | .......................................^`,
```

Both the parsed and checked expressions contain source position information
about each node that appears in the output AST. This information can be used
to determine error locations at evaluation time as well.

## Install

CEL-Go supports `modules` and uses semantic versioning. For more info
see the [Go Modules](https://github.com/golang/go/wiki/Modules) docs.

And of course, there is always the option to build from source directly.

## Common Questions

### Why not JavaScript, Lua, or WASM?

JavaScript and Lua are rich languages that require sandboxing to execute
safely. Sandboxing is costly and factors into the "what will I let users
evaluate?" question heavily when the answer is anything more than O(n)
complexity.

CEL evaluates linearly with respect to the size of the expression and the input
being evaluated when macros are disabled. The only functions beyond the
built-ins that may be invoked are provided by the host environment. While
extension functions may be more complex, this is a choice by the application
embedding CEL.

But, why not WASM? WASM is an excellent choice for certain applications and
is far superior to embedded JavaScript and Lua, but it does not have support
for garbage collection and non-primitive object types require semi-expensive
calls across modules. In most cases CEL will be faster and just as portable
for its intended use case, though for node.js and web-based execution CEL
too may offer a WASM evaluator with direct to WASM compilation.

### Do I need to Parse _and_ Check?

Checking is an optional, but strongly suggested step in CEL expression
validation. It is sufficient in some cases to simply parse and rely on the
runtime bindings and error handling to do the right thing.

### Where can I learn more about the language?

* See the [CEL Spec][1] for the specification and conformance test suite.
* Ask for support on the [CEL Go Discuss][2] Google group.

### Where can I learn more about the internals?

* See [GoDoc][6] to learn how to integrate CEL into services written in Go.
* See the [CEL C++][3] toolchain (under development) for information about how
  to integrate CEL evaluation into other environments.

### How can I contribute?

* See [CONTRIBUTING.md](./CONTRIBUTING.md) to get started.
* Use [GitHub Issues][4] to request features or report bugs.

### Some tests don't work with `go test`?

A handful of tests rely on [Bazel][5]. In particular dynamic proto support
at check time and the conformance test driver require Bazel to coordinate
the test inputs:

```sh
bazel test ...
```

## License

Released under the [Apache License](LICENSE).

[1]:  https://github.com/google/cel-spec
[2]:  https://groups.google.com/forum/#!forum/cel-go-discuss
[3]:  https://github.com/google/cel-cpp
[4]:  https://github.com/google/cel-go/issues
[5]:  https://bazel.build
[6]:  https://godoc.org/github.com/google/cel-go


cel-go

A simple embeddable scripting language which supports concurrent event processing

ECAL
====

<p align="center">
  <img height="150px" style="height:150px;" src="ecal-support/images/logo.png">
</p>

ECAL is an ECA (Event Condition Action) language for concurrent event processing. ECAL can define event-based systems using rules which are triggered by events. ECAL is intended to be embedded into other software to provide an easy to use scripting language which can react to external events.

[![Code coverage](https://void.devt.de/pub/ecal/test_result.svg)](https://void.devt.de/pub/ecal/coverage.txt)
[![Go Report Card](https://goreportcard.com/badge/devt.de/krotik/ecal?style=flat-square)](https://goreportcard.com/report/devt.de/krotik/ecal)
[![Go Reference](https://pkg.go.dev/badge/krotik/ecal.svg)](https://pkg.go.dev/devt.de/krotik/ecal)
[![Mentioned in Awesome Go](https://awesome.re/mentioned-badge-flat.svg)](https://github.com/avelino/awesome-go)

Features
--------
- Simple intuitive syntax.
- Minimalistic base language (by default only writing to a log is supported).
- Language can be easily extended either by auto generating bridge adapters to Go functions or by adding custom function into the standard library (stdlib).
- External events can be easily pushed into the interpreter and scripts written in ECAL can react to these events.
- Simple but powerful concurrent event-based processing supporting priorities and scoping for control flow.
- Handling event rules can match on event state and rules can suppress each other.

### Getting started

You can either download a pre-compiled package for Windows (win64) or Linux (amd64) [here](https://void.devt.de/pub/ecal) or clone the repository and build the ECAL executable with a simple `make` command. You need Go 1.14 or higher.

Run `./ecal` to start an interactive session. You can now write simple one line statements and evaluate them:

```
>>>a:=2;b:=a*4;a+b
10
>>>"Result is {{a+b}}"
Result is 10
```

Close the interpreter by pressing <ctrl>+d and change into the directory `examples/fib`.
There are 2 ECAL files in here:

lib.ecal
```
# Library for fib

/*
fib calculates the fibonacci series using recursion.
*/
func fib(n) {
    if (n <= 1) {
        return n
    }
    return fib(n-1) + fib(n-2)
}
```

fib.ecal
```
import "lib.ecal" as lib

for a in range(2, 20, 2) {
  log("fib({{a}}) = ", lib.fib(a))
}
```

Run the ECAL program with: `sh run.sh`. The output should be like:
```
$ sh run.sh
2000/01/01 12:12:01 fib(2) = 1
2000/01/01 12:12:01 fib(4) = 3
2000/01/01 12:12:01 fib(6) = 8
2000/01/01 12:12:01 fib(8) = 21
2000/01/01 12:12:01 fib(10) = 55
2000/01/01 12:12:01 fib(12) = 144
2000/01/01 12:12:02 fib(14) = 377
2000/01/01 12:12:02 fib(16) = 987
2000/01/01 12:12:02 fib(18) = 2584
2000/01/01 12:12:02 fib(20) = 6765
```

The interpreter can be run in debug mode which adds debug commands to the console. Run the ECAL program in debug mode with: `sh debug.sh` - this will also start a debug server which external development environments can connect to. There is a [VSCode integration](ecal-support/README.md) available which allows debugging via a graphical interface.

It is possible to package your ECAL project into an executable that can be run without a separate ECAL interpreter. Run the `sh pack.sh` and see the script for details.

### Embedding ECAL and using event processing

The primary purpose of ECAL is to be a simple multi-purpose language which can be embedded into other software:
- It has a minimal (quite generic) syntax.
- By default the language can only reach outside the interpreter via return values, injecting events or logging.
- External systems can interact with the code via events which maybe be handled in sink systems with varying complexity.
- A standard library of function can easily be created by either generating proxy code to standard Go functions or by adding simple straight-forward function objects.

The core of the ECAL interpreter is the runtime provider object which is constructed with a given logger and import locator. The import locator is used by the import statement to load other ECAL code at runtime. The logger is used to process log statements from the interpreter.
```
logger := util.NewStdOutLogger()
importLocator := &util.FileImportLocator{Root: "/somedir"}
rtp := interpreter.NewECALRuntimeProvider("Some Program Title", importLocator, logger)
```
The ECALRuntimeProvider provides additionally to the logger and import locator also the following: A cron object to schedule recurring events. An ECA processor which triggers sinks and can be used to inject events into the interpreter. A debugger object which can be used to debug ECAL code supporting thread suspension, thread inspection, value injection and extraction and stepping through statements.

The actual ECAL code has to be first parsed into an Abstract Syntax Tree. The tree is annotated during its construction with runtime components created by the runtime provider.
```
ast, err := parser.ParseWithRuntime("sourcefilename", code, rtp)
```
The code is executed by calling the Validate() and Eval() function.
```
err = ast.Runtime.Validate()
vs := scope.NewScope(scope.GlobalScope)
res, err := ast.Runtime.Eval(vs, make(map[string]interface{}), threadId)
```
Eval is given a variable scope which stores the values of variables, an instance state for internal use and a thread ID identifying the executing thread.

If events are to be used then the processor of the runtime provider needs to be started first.
```
rtp.Processor.Start()
```
The processor must be started *after* all sinks have been declared and *before* events are thrown.

Events can then be injected into the interpreter.
```
monitor, err := rtp.Processor.AddEventAndWait(engine.NewEvent("MyEvent", []string{"foo", "bar", "myevent"}, map[interface{}]interface{}{
  "data1": 123,
  "data2": "123",
}), nil)
```
All errors are collected in the returned monitor.
```
monitor.RootMonitor().AllErrors()
```
The above event could be handled in ECAL with the following sinks:
```
sink mysink
  kindmatch [ "foo.bar.myevent" ],
{
  log("Got event: ", event)
}

sink mysink2
  kindmatch [ "foo.*.*" ],
{
  log("Got event: ", event)
}
```

### Using Go plugins in ECAL

ECAL supports to extend the standard library (stdlib) functions via [Go plugins](https://golang.org/pkg/plugin/). The intention of this feature is to allow easy expansion of the standard library even with platform dependent code.

Go plugins come with quite a few extra [requirements and drawbacks](https://www.reddit.com/r/golang/comments/b6h8qq/is_anyone_actually_using_go_plugins/) and should be considered carefully. One major requirement is that `CGO_ENABLED` must be enabled because plugins use the libc dynamic linker. Using [CGO](https://blog.golang.org/cgo) means that cross-platform compilation is difficult as the compilation requires platform specific system libraries.

ECAL stdlib functions defined in plugins must conform to the following interface:
```
/*
ECALPluginFunction models a callable function in ECAL which can be imported via a plugin.
*/
type ECALPluginFunction interface {

	/*
		Run executes this function with a given list of arguments.
	*/
	Run(args []interface{}) (interface{}, error)

	/*
	   DocString returns a descriptive text about this function.
	*/
	DocString() string
}
```

There is a plugin example in the directory `examples/plugin`. The example assumes that the interpreter binary has been compiled with `CGO_ENABLED` which is the default when building the interpreter via the Makefile but not when using the pre-compiled binaries except the Linux binary. The plugin .so file can be compiled with `buildplugin.sh` (the Go compiler must have the same version as the one which compiled the interpreter binary). Running the example with `run.sh` will make the ECAL interpreter load the compiled plugin before executing the ECAL code. The example demonstrates normal and error output. The plugins to load can be defined in a `.ecal.json` file in the interpreter's root directory.

### Further Reading:

- [ECA Language](ecal.md)
- [ECA Engine](engine.md)
- [VSCode integration](ecal-support/README.md)

License
-------
ECAL source code is available under the [MIT License](/LICENSE).


ecal

Expression evaluation engine for Go: fast, non-Turing complete, dynamic typing, static typing

<h1><a href="https://expr-lang.org"><img src="https://expr-lang.org/img/logo.png" alt="Zx logo" height="48"align="right"></a> Expr</h1>

[![test](https://github.com/expr-lang/expr/actions/workflows/test.yml/badge.svg)](https://github.com/expr-lang/expr/actions/workflows/test.yml) 
[![Go Report Card](https://goreportcard.com/badge/github.com/expr-lang/expr)](https://goreportcard.com/report/github.com/expr-lang/expr) 
[![Fuzzing Status](https://oss-fuzz-build-logs.storage.googleapis.com/badges/expr.svg)](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:expr)
[![GoDoc](https://godoc.org/github.com/expr-lang/expr?status.svg)](https://godoc.org/github.com/expr-lang/expr)

**Expr** is a Go-centric expression language designed to deliver dynamic configurations with unparalleled accuracy, safety, and speed. 
**Expr** combines simple [syntax](https://expr-lang.org/docs/language-definition) with powerful features for ease of use:

```js
// Allow only admins and moderators to moderate comments.
user.Group in ["admin", "moderator"] || user.Id == comment.UserId
```

```js
// Determine whether the request is in the permitted time window.
request.Time - resource.Age < duration("24h")
```

```js
// Ensure all tweets are less than 240 characters.
all(tweets, len(.Content) <= 240)
```

## Features

**Expr** is a safe, fast, and intuitive expression evaluator optimized for the Go language. 
Here are its standout features:

### Safety and Isolation
* **Memory-Safe**: Expr is designed with a focus on safety, ensuring that programs do not access unrelated memory or introduce memory vulnerabilities.
* **Side-Effect-Free**: Expressions evaluated in Expr only compute outputs from their inputs, ensuring no side-effects that can change state or produce unintended results.
* **Always Terminating**: Expr is designed to prevent infinite loops, ensuring that every program will conclude in a reasonable amount of time.

### Go Integration
* **Seamless with Go**: Integrate Expr into your Go projects without the need to redefine types.

### Static Typing
* Ensures type correctness and prevents runtime type errors.
  ```go
  out, err := expr.Compile(`name + age`)
  // err: invalid operation + (mismatched types string and int)
  // | name + age
  // | .....^
  ```

### User-Friendly
* Provides user-friendly error messages to assist with debugging and development.

### Flexibility and Utility
* **Rich Operators**: Offers a reasonable set of basic operators for a variety of applications.
* **Built-in Functions**: Functions like `all`, `none`, `any`, `one`, `filter`, and `map` are provided out-of-the-box.

### Performance
* **Optimized for Speed**: Expr stands out in its performance, utilizing an optimizing compiler and a bytecode virtual machine. Check out these [benchmarks](https://github.com/antonmedv/golang-expression-evaluation-comparison#readme) for more details.

## Install

```
go get github.com/expr-lang/expr
```

## Documentation

* See [Getting Started](https://expr-lang.org/docs/Getting-Started) page for developer documentation.
* See [Language Definition](https://expr-lang.org/docs/language-definition) page to learn the syntax.

## Examples

[Play Online](https://go.dev/play/p/XCoNXEjm3TS)

```go
package main

import (
	"fmt"
	"github.com/expr-lang/expr"
)

func main() {
	env := map[string]interface{}{
		"greet":   "Hello, %v!",
		"names":   []string{"world", "you"},
		"sprintf": fmt.Sprintf,
	}

	code := `sprintf(greet, names[0])`

	program, err := expr.Compile(code, expr.Env(env))
	if err != nil {
		panic(err)
	}

	output, err := expr.Run(program, env)
	if err != nil {
		panic(err)
	}

	fmt.Println(output)
}
```

[Play Online](https://go.dev/play/p/tz-ZneBfSuw)

```go
package main

import (
	"fmt"
	"github.com/expr-lang/expr"
)

type Tweet struct {
	Len int
}

type Env struct {
	Tweets []Tweet
}

func main() {
	code := `all(Tweets, {.Len <= 240})`

	program, err := expr.Compile(code, expr.Env(Env{}))
	if err != nil {
		panic(err)
	}

	env := Env{
		Tweets: []Tweet{{42}, {98}, {69}},
	}
	output, err := expr.Run(program, env)
	if err != nil {
		panic(err)
	}

	fmt.Println(output)
}
```

## Who uses Expr?

* [Google](https://google.com) uses Expr as one of its expression languages on the [Google Cloud Platform](https://cloud.google.com).
* [Uber](https://uber.com) uses Expr to allow customization of its Uber Eats marketplace.
* [GoDaddy](https://godaddy.com) employs Expr for the customization of its GoDaddy Pro product.
* [ByteDance](https://bytedance.com) incorporates Expr into its internal business rule engine.
* [Aviasales](https://aviasales.ru) utilizes Expr as a business rule engine for its flight search engine.
* [Alibaba](https://alibaba.com) uses Expr in a web framework for building recommendation services.
* [Argo](https://argoproj.github.io) integrates Expr into Argo Rollouts and Argo Workflows for Kubernetes.
* [Wish.com](https://www.wish.com) employs Expr in its decision-making rule engine for the Wish Assistant.
* [OpenTelemetry](https://opentelemetry.io) integrates Expr into the OpenTelemetry Collector.
* [Philips Labs](https://github.com/philips-labs/tabia) employs Expr in Tabia, a tool designed to collect insights on their code bases.
* [CrowdSec](https://crowdsec.net) incorporates Expr into its security automation tool.
* [CoreDNS](https://coredns.io) uses Expr in CoreDNS, which is a DNS server.
* [qiniu](https://www.qiniu.com) implements Expr in its trade systems.
* [Junglee Games](https://www.jungleegames.com/) uses Expr for its in-house marketing retention tool, Project Audience.
* [Faceit](https://www.faceit.com) uses Expr to enhance customization of its eSports matchmaking algorithm.
* [Chaos Mesh](https://chaos-mesh.org) incorporates Expr into Chaos Mesh, a cloud-native Chaos Engineering platform.
* [Visually.io](https://visually.io) employs Expr as a business rule engine for its personalization targeting algorithm.
* [Akvorado](https://github.com/akvorado/akvorado) utilizes Expr to classify exporters and interfaces in network flows.
* [keda.sh](https://keda.sh) uses Expr to allow customization of its Kubernetes-based event-driven autoscaling.
* [Span Digital](https://spandigital.com/) uses Expr in its Knowledge Management products.
* [Xiaohongshu](https://www.xiaohongshu.com/) combining yaml with Expr for dynamically policies delivery.
* [Melrōse](https://melrōse.org) uses Expr to implement its music programming language.
* [Tork](https://www.tork.run/) integrates Expr into its workflow execution.
* [Critical Moments](https://criticalmoments.io) uses Expr for its mobile realtime conditional targeting system.
* [WoodpeckerCI](https://woodpecker-ci.org) uses Expr for [filtering workflows/steps](https://woodpecker-ci.org/docs/usage/workflow-syntax#evaluate).
* [FastSchema](https://github.com/fastschema/fastschema) - A BaaS leveraging Expr for its customizable and dynamic Access Control system.
* [WunderGraph Cosmo](https://github.com/wundergraph/cosmo) - GraphQL Federeration Router uses Expr to customize Middleware behaviour
* [SOLO](https://solo.one) uses Expr interally to allow dynamic code execution with custom defined functions.
* [Naoma.AI](https://www.naoma.ai) uses Expr as a part of its call scoring engine.
* [GlassFlow.dev](https://github.com/glassflow/clickhouse-etl) uses Expr to do realtime data transformation in ETL pipelines
* [Kargo](https://kargo.io/) uses Expr to evaluate and manipulate variables dynamically during [promotion steps](https://docs.kargo.io/user-guide/reference-docs/expressions/)

[Add your company too](https://github.com/expr-lang/expr/edit/master/README.md)

## License

[MIT](https://github.com/expr-lang/expr/blob/master/LICENSE)

<p align="center"><img src="https://expr-lang.org/img/gopher-small.png" width="150" /></p>


expr

Embeddable scripting programming language

# Gentee script programming language

[![Build Status](https://travis-ci.org/gentee/gentee.png)](https://travis-ci.org/gentee/gentee)
[![Go Report Card](https://goreportcard.com/badge/github.com/gentee/gentee)](https://goreportcard.com/report/github.com/gentee/gentee)
[![GoDoc](https://godoc.org/github.com/gentee/gentee?status.svg)](https://godoc.org/github.com/gentee/gentee)

Gentee is a free open source script programming language. The Gentee programming language is designed to create scripts to automate repetitive actions and processes on your computer. If you use or plan to use .bat files, bash, PowerShell or special programs to automate actions, then try doing the same thing with Gentee. 

Want to see a sample application that successfully uses the Gentee programming language? Take a look at **[Eonza](https://www.eonza.org/)**, a free cross-platform program for easy creation and management of scripts.

## Documentation

- [Gentee programming language (English)](https://docs.gentee.org/)
- [Язык программирования Gentee (Russian)](https://ru.gentee.org/)

All documentation is available on [GitHub](https://github.com/gentee/docs-gentee). 

## Download

- [Linux amd64](https://github.com/gentee/gentee/releases/download/v1.20.0/gentee-1.20.0-linux-amd64.zip)
- [Windows amd64](https://github.com/gentee/gentee/releases/download/v1.20.0/gentee-1.20.0-windows-amd64.zip)
- [macOS amd64](https://github.com/gentee/gentee/releases/download/v1.20.0/gentee-1.20.0-darwin-amd64.zip)

You can download other binary distributions for Linux, macOS, Windows [here](https://github.com/gentee/gentee/releases).

## Go integration

You can use the Gentee compiler and virtual machine in **golang** projects without any restrictions.  
Documentation is available [here](https://docs.gentee.org/golang/howtouse).

## How to run Gentee scripts

* [Download the binary version](https://github.com/gentee/gentee/releases) of Gentee compiler for your operating system or build the *gentee* executable file from *cli/gentee.go* using [go compiler](https://golang.org/dl/).
```
$ go get -u github.com/gentee/gentee
$ cd gentee/gentee/cli
$ go build
```
* Specify the script file when running *gentee*. The script file can have any extension.
```
Linux: ./gentee myscript.g 
Wndows: gentee.exe myscript.g
```
* Also, you can associate the *gentee* program with script files in your operating system.

### Gentee compiler/interpreter

```gentee [-ver] [-t] <scriptname> [command-line parameters for script]```

By default, the program prints the output of the script to the console and returns 0 if successful.

#### Command line parameters

* **scriptname** - full or relative path to the script file. You can specify the command line parameters for the script after the script file name.
* **-ver** - show the current version of Gentee language.
* **-t** - test the script. When using this parameter, the script must have the **result** parameter in the header with the expected value ([example](https://github.com/gentee/gentee/blob/master/test/scripts/ok.g)). In this mode, the program does not output the result of 
the script execution to the console. If the result does not match, an error message is displayed and an error code 4 is returned.

#### Error code

Code | Description
-----|----------
1 | The script file was not found.
2 | Compilation error.
3 | Runtime Error.
4 | The result is erroneous at start with the **-t** parameter.

## Support

If you have any questions and suggestions or would like to help in the development, [add your issue here](https://github.com/gentee/gentee/issues).

## License

[MIT](https://github.com/gentee/gentee/blob/master/LICENSE)

Copyright (c) 2018-present, Alexey Krivonogov


gentee

# PHP bindings for Go

[![API Documentation][godoc-svg]][godoc-url] [![MIT License][license-svg]][license-url]

This package implements support for executing PHP scripts, exporting Go variables for use in PHP contexts, attaching Go method receivers as PHP classes and returning PHP variables for use in Go contexts.

Both PHP 5.x and PHP 7.x series are supported.

## Building

Building this package requires that you have PHP installed as a library. For most Linux systems, this can usually be found in the `php-embed` package, or variations thereof.

Once the PHP library is available, the bindings can be compiled with `go build` and are `go get`-able.

**Note**: Building against PHP 5.x requires that the `php5` tag is provided, i.e.:

```bash
go get -tags php5 github.com/deuill/go-php
```

This is due to the fact that PHP 7.x is the default build target.

## Status

Executing PHP [script files][Context.Exec] as well as [inline strings][Context.Eval] is supported and stable.

[Binding Go values][NewValue] as PHP variables is allowed for most base types, and PHP values returned from eval'd strings can be converted and used in Go contexts as `interface{}` values.

It is possible to [attach Go method receivers][NewReceiver] as PHP classes, with full support for calling expored methods, as well as getting and setting embedded fields (for `struct`-type method receivers).

### Caveats

Be aware that, by default, PHP is **not** designed to be used in multithreaded environments (which severely restricts the use of these bindings with Goroutines) if not built with [ZTS support](https://secure.php.net/manual/en/pthreads.requirements.php). However, ZTS support has seen major refactoring between PHP 5 and PHP 7, and as such is currently unsupported by this package.

Currently, it is recommended to either sync use of seperate Contexts between Goroutines, or share a single Context among all running Goroutines.

## Roadmap

Currently, the package lacks in several respects:

  * ZTS/multi-threading support. This basically means using Go-PHP in Goroutines is severely limited.
  * Documentation and examples, both package-level and external.
  * Performance. There's no reason to believe Go-PHP suffers from any serious performance issues in particular, but adding benchmarks, especially compared against vanilla PHP, might help.
  * Your feature request here?

These items will be tackled in order of significance (which may not be the order shown above).

## Usage

### Basic

Executing a script is simple:

```go
package main

import (
    php "github.com/deuill/go-php"
    "os"
)

func main() {
    engine, _ := php.New()

    context, _ := engine.NewContext()
    context.Output = os.Stdout

    context.Exec("index.php")
    engine.Destroy()
}
```

The above will execute script file `index.php` located in the current folder and will write any output to the `io.Writer` assigned to `Context.Output` (in this case, the standard output).

### Binding and returning variables

The following example demonstrates binding a Go variable to the running PHP context, and returning a PHP variable for use in Go:

```go
package main

import (
    "fmt"
    php "github.com/deuill/go-php"
)

func main() {
    engine, _ := php.New()
    context, _ := engine.NewContext()

    var str string = "Hello"
    context.Bind("var", str)

    val, _ := context.Eval("return $var.' World';")
    fmt.Printf("%s", val.Interface())
    // Prints 'Hello World' back to the user.

    engine.Destroy()
}
```

A string value "Hello" is attached using `Context.Bind` under a name `var` (available in PHP as `$var`). A script is executed inline using `Context.Eval`, combinding the attached value with a PHP string and returning it to the user.

Finally, the value is returned as an `interface{}` using `Value.Interface()` (one could also use `Value.String()`, though the both are equivalent in this case).

## License

All code in this repository is covered by the terms of the MIT License, the full text of which can be found in the LICENSE file.

[godoc-url]: https://godoc.org/github.com/deuill/go-php
[godoc-svg]: https://godoc.org/github.com/deuill/go-php?status.svg

[license-url]: https://github.com/deuill/go-php/blob/master/LICENSE
[license-svg]: https://img.shields.io/badge/license-MIT-blue.svg

[Context.Exec]: https://godoc.org/github.com/deuill/go-php/engine#Context.Exec
[Context.Eval]: https://godoc.org/github.com/deuill/go-php/engine#Context.Eval
[NewValue]:     https://godoc.org/github.com/deuill/go-php/engine#NewValue
[NewReceiver]:  https://godoc.org/github.com/deuill/go-php/engine#NewReceiver


go-php

go-python
=========

**`sbinet/go-python` only supports CPython2. CPython2 isn't supported anymore by [python.org](https://python.org). Thus, `sbinet/go-python` is now archived.**
**A possible alternative may be to use and contribute to [go-python/cpy3](https://github.com/go-python/cpy3) instead.**

[![Build Status](https://travis-ci.org/sbinet/go-python.svg?branch=master)](https://travis-ci.org/sbinet/go-python)
[![Build status](https://ci.appveyor.com/api/projects/status/n0ujg8no487a89vo/branch/master?svg=true)](https://ci.appveyor.com/project/sbinet/go-python/branch/master)
[![GoDocs](https://godocs.io/github.com/sbinet/go-python?status.svg)](https://godocs.io/github.com/sbinet/go-python)

Naive `go` bindings towards the C-API of CPython-2.

this package provides a ``go`` package named "python" under which most of the ``PyXYZ`` functions and macros of the public C-API of CPython have been exposed.

theoretically, you should be able to just look at:

  http://docs.python.org/c-api/index.html

and know what to type in your ``go`` program.


this package also provides an executable "go-python" which just loads "python" and then call ``python.Py_Main(os.Args)``.
the rational being that under such an executable, ``go`` based extensions for C-Python would be easier to implement (as this usually means calling into ``go`` from ``C`` through some rather convoluted functions hops)


## Install

With `Go 1` and the ``go`` tool, ``cgo`` packages can't pass anymore
additional ``CGO_CFLAGS`` from external programs (except `pkg-config`)
to the "fake" ``#cgo`` preprocessor directive.

``go-python`` now uses ``pkg-config`` to get the correct location of
headers and libraries.
Unfortunately, the naming convention for the ``pkg-config`` package is
not standardised across distributions and OSes, so you may have to
edit the ``cgoflags.go`` file accordingly.

```sh
 $ go get github.com/sbinet/go-python
```

If ``go get`` + ``pkg-config`` failed:

```sh
 $ cd go-python
 $ edit cgoflags.go
 $ make VERBOSE=1
```

*Note*: you'll need the proper header and `python` development environment. On Debian, you'll need to install the ``python-all-dev`` package

Documentation
-------------

Is available on ``godocs``:

 https://godocs.io/github.com/sbinet/go-python


Example:
--------

```go
package main

import "fmt"
import "github.com/sbinet/go-python"

func init() {
   err := python.Initialize()
   if err != nil {
          panic(err.Error())
   } 
}

func main() {
 	 gostr := "foo" 
	 pystr := python.PyString_FromString(gostr)
	 str := python.PyString_AsString(pystr)
	 fmt.Println("hello [", str, "]")
}
```

```sh
$ go run ./main.go
hello [ foo ]
```

TODO:
-----

 - fix handling of integers (I did a poor job at making sure everything was ok)

 - add CPython unit-tests

 - do not expose ``C.FILE`` pointer and replace it with ``os.File`` in "go-python" API

 - provide an easy way to extend go-python with ``go`` based extensions

 - think about the need (or not) to translate CPython exceptions into go panic/recover mechanism

 - use SWIG to automatically wrap the whole CPython api ?


go-python

**Mirror closed because of 2FA, now only at https://codeberg.org/anaseto/goal**

# Goal

[![pkg.go.dev](https://pkg.go.dev/badge/codeberg.org/anaseto/goal.svg)](https://pkg.go.dev/codeberg.org/anaseto/goal)
[![godocs.io](https://godocs.io/codeberg.org/anaseto/goal?status.svg)](https://godocs.io/codeberg.org/anaseto/goal)

Goal is an embeddable array programming language with a bytecode interpreter,
written in Go. It provides both a command line intepreter (that can be used in
the REPL), and a library interface. The core features are mostly there and
tested, so Goal is usable both for writing useful short scripts and playing
with the REPL. User testing and bug reports are welcome!

Like in most array programming languages, Goal's builtins vectorize operations
on immutable arrays, and encourage a functional style for control and data
transformations, supported by a simple dynamic type system with little
abstraction, and mutable variables (but no mutable values).

It's main distinctive features are as follows:

* Syntax inspired mainly from the K language, but with quite a few deviations.
  For example, backquotes produce Go-like raw strings instead of symbols,
  `rx/\s+/` is a compile-time regular expression literal, and there is
  Perl-style string interpolation. On the other side, there are no tacit
  compositions, and digraph operator verbs and adverbs are gone or done
  differently (except for global assignment with ::).
* Primitive semantics are both inspired from the
  [ngn/k](https://codeberg.org/ngn/k) variant of the K language and
  [BQN](https://mlochbaum.github.io/BQN/index.html). For example, group by,
  classify, shifts, windows, binary search and occurrence count take after
  BQN's semantics, but free-form immutable arrays, dictionaries and adverbs
  take after K.
* Unlike in typical array languages, strings are atoms, and common string
  handling functions have been integrated into the primitives, including
  regular expression functions. Primitives acting on whole strings are
  Unicode-aware (like case-folding or Unicode properties in regexps).
* Error handling makes a distinction between fatal errors (panics) and
  recoverable errors which are handled as values.
* Integrated support for csv, json, time handling, and basic math.
* Simple IO: read/write files, run commands/pipes, open filehandles.
* Easily embeddable and extensible in Go.
* Array performance is quite decent, with specialized algorithms depending on
  inputs (type, size, range), and variable liveness analysis that reduces
  cloning by reusing dead immutable arrays (in code with limited branching).
  However, it is not a goal to reach state-of-the-art (no SIMD, and no bit
  booleans, fitting integers in arrays using either uint8 or int64 elements).
+ Scalar performance is typical for a bytecode-compiled interpreter (without
  JIT), somewhat slower than a C bytecode interpreter: value representation is
  less compact than how it could be done in C, but Goal does have unboxed
  integers and floats.

If this list is not enough to satisfy your curiosity, have a look at the [why
section](https://anaseto.codeberg.page/goal/chap-FAQ.html#why) of the FAQ.  You
can also read the [Credits.md](Credits.md) to know about main inspiration
sources for the language. Last, but not least, there are some [implementation
notes](docs/Implementation.md) too.

# Install

To install the command line interpreter, first do the following:

* Install the [go compiler](https://golang.org/).
* Add `$(go env GOPATH)/bin` to your `$PATH` (for example `export PATH="$PATH:$(go env GOPATH)/bin"`).

Then you can build the intepreter with:

	go install ./cmd/goal

Alternatively, you may type `go build -o /path/to/bin/goal ./cmd/goal` to put
the resulting binary in a custom location in your $PATH.

The `goal` command should now be available. Type `goal --help` for command-line
usage.

Typing just `goal` opens the REPL. For a better experience using the REPL (to
get typical keyboard shortcuts), you can install the readline wrapper `rlwrap`
program (available as a package in most systems), and then use instead `rlwrap
goal`.

# Links

* [Goal docs](https://anaseto.codeberg.page/goal/) : work-in-progress
  documentation for Goal.
* [vim-goal](https://codeberg.org/anaseto/vim-goal) : vim files for Goal.
* [APL Farm](https://matrix.to/#/#aplfarm:matrix.org) : chat about array
  languages.

# Documentation

In addition to the work-in-progress [documentation
website](https://anaseto.codeberg.page/goal/), you might be interested in the
[Changelog](Changes.md) changes between releases. The REPL help is also
available in text form here at [docs/help.txt](docs/help.txt).

# Examples

A few short examples can be found in the `examples` and `testdata/scripts`
directory. Because the latter are used for testing, they come along an expected
result after a `/RESULT:` comment.

Also, various code generation scripts in the toplevel `scripts` directory are
written in Goal.


goal

goja
====

ECMAScript 5.1(+) implementation in Go.

[![Go Reference](https://pkg.go.dev/badge/github.com/dop251/goja.svg)](https://pkg.go.dev/github.com/dop251/goja)

Goja is an implementation of ECMAScript 5.1 in pure Go with emphasis on standard compliance and
performance.

This project was largely inspired by [otto](https://github.com/robertkrimen/otto).

The minimum required Go version is 1.20.

Features
--------

 * Full ECMAScript 5.1 support (including regex and strict mode).
 * Passes nearly all [tc39 tests](https://github.com/tc39/test262) for the features implemented so far. The goal is to
   pass all of them. See .tc39_test262_checkout.sh for the latest working commit id.
 * Capable of running Babel, Typescript compiler and pretty much anything written in ES5.
 * Sourcemaps.
 * Most of ES6 functionality, still work in progress, see https://github.com/dop251/goja/milestone/1?closed=1

Known incompatibilities and caveats
-----------------------------------

### WeakMap
WeakMap is implemented by embedding references to the values into the keys. This means that as long
as the key is reachable all values associated with it in any weak maps also remain reachable and therefore
cannot be garbage collected even if they are not otherwise referenced, even after the WeakMap is gone.
The reference to the value is dropped either when the key is explicitly removed from the WeakMap or when the
key becomes unreachable.

To illustrate this:

```javascript
var m = new WeakMap();
var key = {};
var value = {/* a very large object */};
m.set(key, value);
value = undefined;
m = undefined; // The value does NOT become garbage-collectable at this point
key = undefined; // Now it does
// m.delete(key); // This would work too
```

The reason for it is the limitation of the Go runtime. At the time of writing (version 1.15) having a finalizer
set on an object which is part of a reference cycle makes the whole cycle non-garbage-collectable. The solution
above is the only reasonable way I can think of without involving finalizers. This is the third attempt
(see https://github.com/dop251/goja/issues/250 and https://github.com/dop251/goja/issues/199 for more details).

Note, this does not have any effect on the application logic, but may cause a higher-than-expected memory usage.

### WeakRef and FinalizationRegistry
For the reason mentioned above implementing WeakRef and FinalizationRegistry does not seem to be possible at this stage.

### JSON
`JSON.parse()` uses the standard Go library which operates in UTF-8. Therefore, it cannot correctly parse broken UTF-16
surrogate pairs, for example:

```javascript
JSON.parse(`"\\uD800"`).charCodeAt(0).toString(16) // returns "fffd" instead of "d800"
```

### Date
Conversion from calendar date to epoch timestamp uses the standard Go library which uses `int`, rather than `float` as per
ECMAScript specification. This means if you pass arguments that overflow int to the `Date()` constructor or  if there is
an integer overflow, the result will be incorrect, for example:

```javascript
Date.UTC(1970, 0, 1, 80063993375, 29, 1, -288230376151711740) // returns 29256 instead of 29312
```

FAQ
---

### How fast is it?

Although it's faster than many scripting language implementations in Go I have seen
(for example it's 6-7 times faster than otto on average) it is not a
replacement for V8 or SpiderMonkey or any other general-purpose JavaScript engine.
You can find some benchmarks [here](https://github.com/dop251/goja/issues/2).

### Why would I want to use it over a V8 wrapper?

It greatly depends on your usage scenario. If most of the work is done in javascript
(for example crypto or any other heavy calculations) you are definitely better off with V8.

If you need a scripting language that drives an engine written in Go so that
you need to make frequent calls between Go and javascript passing complex data structures
then the cgo overhead may outweigh the benefits of having a faster javascript engine.

Because it's written in pure Go there are no cgo dependencies, it's very easy to build and it
should run on any platform supported by Go.

It gives you a much better control over execution environment so can be useful for research.

### Is it goroutine-safe?

No. An instance of goja.Runtime can only be used by a single goroutine
at a time. You can create as many instances of Runtime as you like but
it's not possible to pass object values between runtimes.

### Where is setTimeout()/setInterval()?

setTimeout() and setInterval() are common functions to provide concurrent execution in ECMAScript environments, but the two functions are not part of the ECMAScript standard.
Browsers and NodeJS just happen to provide similar, but not identical, functions. The hosting application need to control the environment for concurrent execution, e.g. an event loop, and supply the functionality to script code.

There is a [separate project](https://github.com/dop251/goja_nodejs) aimed at providing some NodeJS functionality,
and it includes an event loop.

### Can you implement (feature X from ES6 or higher)?

I will be adding features in their dependency order and as quickly as time permits. Please do not ask
for ETAs. Features that are open in the [milestone](https://github.com/dop251/goja/milestone/1) are either in progress
or will be worked on next.

The ongoing work is done in separate feature branches which are merged into master when appropriate.
Every commit in these branches represents a relatively stable state (i.e. it compiles and passes all enabled tc39 tests),
however because the version of tc39 tests I use is quite old, it may be not as well tested as the ES5.1 functionality. Because there are (usually) no major breaking changes between ECMAScript revisions
it should not break your existing code. You are encouraged to give it a try and report any bugs found. Please do not submit fixes though without discussing it first, as the code could be changed in the meantime.

### How do I contribute?

Before submitting a pull request please make sure that:

- You followed ECMA standard as close as possible. If adding a new feature make sure you've read the specification,
do not just base it on a couple of examples that work fine.
- Your change does not have a significant negative impact on performance (unless it's a bugfix and it's unavoidable)
- It passes all relevant tc39 tests.

Current Status
--------------

 * There should be no breaking changes in the API, however it may be extended.
 * Some of the AnnexB functionality is missing.

Basic Example
-------------

Run JavaScript and get the result value.

```go
vm := goja.New()
v, err := vm.RunString("2 + 2")
if err != nil {
    panic(err)
}
if num := v.Export().(int64); num != 4 {
    panic(num)
}
```

Passing Values to JS
--------------------
Any Go value can be passed to JS using Runtime.ToValue() method. See the method's [documentation](https://pkg.go.dev/github.com/dop251/goja#Runtime.ToValue) for more details.

Exporting Values from JS
------------------------
A JS value can be exported into its default Go representation using Value.Export() method.

Alternatively it can be exported into a specific Go variable using [Runtime.ExportTo()](https://pkg.go.dev/github.com/dop251/goja#Runtime.ExportTo) method.

Within a single export operation the same Object will be represented by the same Go value (either the same map, slice or
a pointer to the same struct). This includes circular objects and makes it possible to export them.

Calling JS functions from Go
----------------------------
There are 2 approaches:

- Using [AssertFunction()](https://pkg.go.dev/github.com/dop251/goja#AssertFunction):
```go
const SCRIPT = `
function sum(a, b) {
    return +a + b;
}
`

vm := goja.New()
_, err := vm.RunString(SCRIPT)
if err != nil {
    panic(err)
}
sum, ok := goja.AssertFunction(vm.Get("sum"))
if !ok {
    panic("Not a function")
}

res, err := sum(goja.Undefined(), vm.ToValue(40), vm.ToValue(2))
if err != nil {
    panic(err)
}
fmt.Println(res)
// Output: 42
```
- Using [Runtime.ExportTo()](https://pkg.go.dev/github.com/dop251/goja#Runtime.ExportTo):
```go
const SCRIPT = `
function sum(a, b) {
    return +a + b;
}
`

vm := goja.New()
_, err := vm.RunString(SCRIPT)
if err != nil {
    panic(err)
}

var sum func(int, int) int
err = vm.ExportTo(vm.Get("sum"), &sum)
if err != nil {
    panic(err)
}

fmt.Println(sum(40, 2)) // note, _this_ value in the function will be undefined.
// Output: 42
```

The first one is more low level and allows specifying _this_ value, whereas the second one makes the function look like
a normal Go function.

Mapping struct field and method names
-------------------------------------
By default, the names are passed through as is which means they are capitalised. This does not match
the standard JavaScript naming convention, so if you need to make your JS code look more natural or if you are
dealing with a 3rd party library, you can use a [FieldNameMapper](https://pkg.go.dev/github.com/dop251/goja#FieldNameMapper):

```go
vm := goja.New()
vm.SetFieldNameMapper(TagFieldNameMapper("json", true))
type S struct {
    Field int `json:"field"`
}
vm.Set("s", S{Field: 42})
res, _ := vm.RunString(`s.field`) // without the mapper it would have been s.Field
fmt.Println(res.Export())
// Output: 42
```

There are two standard mappers: [TagFieldNameMapper](https://pkg.go.dev/github.com/dop251/goja#TagFieldNameMapper) and
[UncapFieldNameMapper](https://pkg.go.dev/github.com/dop251/goja#UncapFieldNameMapper), or you can use your own implementation.

Native Constructors
-------------------

In order to implement a constructor function in Go use `func (goja.ConstructorCall) *goja.Object`.
See [Runtime.ToValue()](https://pkg.go.dev/github.com/dop251/goja#Runtime.ToValue) documentation for more details.

Regular Expressions
-------------------

Goja uses the embedded Go regexp library where possible, otherwise it falls back to [regexp2](https://github.com/dlclark/regexp2).

Exceptions
----------

Any exception thrown in JavaScript is returned as an error of type *Exception. It is possible to extract the value thrown
by using the Value() method:

```go
vm := goja.New()
_, err := vm.RunString(`

throw("Test");

`)

if jserr, ok := err.(*Exception); ok {
    if jserr.Value().Export() != "Test" {
        panic("wrong value")
    }
} else {
    panic("wrong type")
}
```

If a native Go function panics with a Value, it is thrown as a Javascript exception (and therefore can be caught):

```go
var vm *Runtime

func Test() {
    panic(vm.ToValue("Error"))
}

vm = goja.New()
vm.Set("Test", Test)
_, err := vm.RunString(`

try {
    Test();
} catch(e) {
    if (e !== "Error") {
        throw e;
    }
}

`)

if err != nil {
    panic(err)
}
```

Interrupting
------------

```go
func TestInterrupt(t *testing.T) {
    const SCRIPT = `
    var i = 0;
    for (;;) {
        i++;
    }
    `

    vm := goja.New()
    time.AfterFunc(200 * time.Millisecond, func() {
        vm.Interrupt("halt")
    })

    _, err := vm.RunString(SCRIPT)
    if err == nil {
        t.Fatal("Err is nil")
    }
    // err is of type *InterruptError and its Value() method returns whatever has been passed to vm.Interrupt()
}
```

NodeJS Compatibility
--------------------

There is a [separate project](https://github.com/dop251/goja_nodejs) aimed at providing some of the NodeJS functionality.


goja

Embeddable Ngaro VM implementation enabling scripting in Retro

[![Build Status](https://travis-ci.org/db47h/ngaro.svg?branch=master)](https://travis-ci.org/db47h/ngaro)
[![Go Report Card](https://goreportcard.com/badge/github.com/db47h/ngaro)](https://goreportcard.com/report/github.com/db47h/ngaro)
[![Coverage Status](https://coveralls.io/repos/github/db47h/ngaro/badge.svg)](https://coveralls.io/github/db47h/ngaro)
[![GoDoc](https://godoc.org/github.com/db47h/ngaro/vm?status.svg)](https://godoc.org/github.com/db47h/ngaro/vm)

# Ngaro Go

## <a name="pkg-overview">Overview</a>
This is an embeddable Go implementation of the [Ngaro Virtual Machine](http://retroforth.org/docs/The_Ngaro_Virtual_Machine.html).

This repository contains the embeddable [virtual
machine](https://godoc.org/github.com/db47h/ngaro/vm), a rudimentary
[symbolic assembler](https://godoc.org/github.com/db47h/ngaro/asm)
for easy bootstrapping of projects written in Ngaro machine language, and the
[retro](https://godoc.org/github.com/db47h/ngaro/cmd/retro) command
line tool that can be used as a replacement for the Retro reference
implementations.

Please visit http://forthworks.com/retro/ to get you started about the Retro
language and the Ngaro Virtual Machine.

The main purpose of this implementation is to allow customization and
communication between Retro programs and Go programs via custom opcodes and
I/O handlers (i.e. scripting Go programs in Retro). The package examples
demonstrate various use cases. For more details on I/O handling in the Ngaro
VM, please refer to http://retroforth.org/docs/The_Ngaro_Virtual_Machine.html.

Another goal is to make the VM core as neutral as possible regarding the higher
level language running on it. For example, the in-memory string encoding scheme
is fully customizable. Retro specific behaviors are provided via the lang/retro
package.

Custom opcodes are implemented by intercepting implicit calls to negative memory
addresses. This allows the VM to be fully backwards compatible with existing
Retro images while still providing enhanced capabilities. The maximum number of
addressable cells is 2^31 when running in 32 bits mode (that's 8GiB or memory on
the host). The range [-2^31 - 1, -1] is available for custom opcodes.

This implementation passes all tests from the retro-language test suite and
its performance when running tests/core.rx is slightly better than with the
reference implementations:

	1.08s for this implementation, no custom opcodes, compiled with Go 1.7, linux/amd64
	1.15s for the reference assembly implementation, linux/386
	1.30s for the reference Go implementation, compiled with Go 1.7, linux/amd64
	2.00s for the reference C implementation, compiled with gcc-5.4 -O3 -fomit-frame-pointer

Yes, Go 1.7's new SSA backend is THAT good on this type of workload :)

For all intents and purposes, the VM behaves according to the specification.
This is of particular importance to implementors of custom opcodes: the VM
always increments the PC after each opcode, thus opcodes altering the PC must
adjust it accordingly (i.e. set it to its real target minus one).

## Installing

Install the retro command line tool:

	go get -u github.com/db47h/ngaro/cmd/retro

Test:

	go test -i github.com/db47h/ngaro/vm
	go test -v github.com/db47h/ngaro/vm/...

Build a retroImage:

	cd $GOPATH/github.com/db47h/ngaro/cmd/retro
	make retroImage

Test the retro command line tool:

	./retro --with vm/testdata/core.rx

Should generate a lot of output. Just check that the last lines look like this:

	ok   summary
	360 tests run: 360 passed, 0 failed.
	186 words checked, 0 words unchecked, 37 i/o words ignored.

	ok  bye

## Support for 32/64 bits memory images on all architectures

Since v2.0.0, the default Cell type (the base data type in Ngaro VM) is Go's
int. This means that depending on the target you compile for, it will be either
32 or 64 bits. The retro command line tool supports loading and saving retro
memory images where Cells can be either size. For example, to quickly get
started you can do this:

	echo "save bye" | \
	retro -image vm/testdata/retroImage -ibits 32 -o retroImage

This will load the memory image file `vm/testdata/retroImage` which we know to
be encoded using 32 bits cells, and save it in the current directory with
whatever encoding is the default for your platform. You could also force a
specific output Cell size with the `-obits` flag.

Loading and saving with encodings different from the target platform is safe:
it will work or generate an error, but never create a corrupted memory
image file. For example, with a 64 bits retro binary, saving to 32 bits cells
will check that written values fit in a 32 bit int. If not, it will generate an
error.

If for some reason you need a specific cell size, regardless of the target
platform's native int size, you can force it by compiling with the tags
`ngaro32` or `ngaro64`:

	go install -tags ngaro32 github.com/db47h/ngaro/cmd/retro

will build a version of retro that uses 32 bits cells, regardless of
`GOOS`/`GOARCH`. Likewise, the `ngaro64` tag will force 64 bits cells, even on
32 bits targets (it'll be twice as slow though).

## Releases

This project uses [semantic
versioning](http://dave.cheney.net/2016/06/24/gophers-please-tag-your-releases)
and tries to adhere to it.

See the [releases page](https://github.com/db47h/ngaro/releases).

For a detailed change log, see the [commit log](https://github.com/db47h/ngaro/commits/master).

## Contributing

No rules, just common sense. Bells, wristles and any other preformance improvements are very
welcome. The only changes that will never be accepted are those that will break compatibility
with the VM specification.

PRs are a good place to discuss changes so do not hesitate to send PRs directly. Or an issue, if your really have an issue.

## Places to Go

Have a look at [@dobegor's fork](https://github.com/dobegor/ngaro). It breaks compatibility with the spec, but
it's got some nice features like floating point support, pausable VM, and a few others in their TODO list.

## License

This project is Copyright 2016 Denis Bernard <db047h@gmail.com>, licensed under
the [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0).

The Retro language and Ngaro Virtual Machine are Copyright (c) 2008-2016 Charles
Childers (and many others), licensed under the ISC license. See the file
LICENSE-RETRO at the root of this repository for more details as well as a full
list of contributors.

Note that all files in the \_misc and vm/testdata folders are verbatim copies
from the retro-language project. As such, only Retro's ISC license applies to
these files.


ngaro

# ![prolog - the only reasonable scripting engine for Go](prolog.gif)

[![Go Reference](https://pkg.go.dev/badge/github.com/ichiban/prolog.svg)](https://pkg.go.dev/github.com/ichiban/prolog)
[![Actions Status](https://github.com/ichiban/prolog/actions/workflows/go.yml/badge.svg)](https://github.com/ichiban/prolog/actions)
[![Go Report Card](https://goreportcard.com/badge/github.com/ichiban/prolog)](https://goreportcard.com/report/github.com/ichiban/prolog)
[![codecov](https://codecov.io/gh/ichiban/prolog/branch/main/graph/badge.svg?token=2FC3PZY7LN)](https://codecov.io/gh/ichiban/prolog)
[![Mentioned in Awesome Go](https://awesome.re/mentioned-badge.svg)](https://github.com/avelino/awesome-go)

## What is this?

`ichiban/prolog` is an embeddable **ISO Prolog** interpreter in **Go**.

- **Standards-compliant:**
  - [ISO/IEC 13211-1:1995 Information technology — Programming languages — Prolog — Part 1: General core](https://www.iso.org/standard/21413.html)
  - [A Prologue for Prolog](http://www.complang.tuwien.ac.at/ulrich/iso-prolog/prologue)
  - [DCGs](https://www.complang.tuwien.ac.at/ulrich/iso-prolog/dcgs/dcgsdraft-2019-06-03.pdf)
- **Easy to integrate:** `database/sql`-like Go API
- **Highly customizable:**
  - Sandboxing
  - Custom predicates in Go
  - Custom terms (data types) in Go

## Comparison with Other Libraries

|             | **prolog**             | otto            | go-lua          |
| ----------- | ---------------------- | --------------- | --------------- |
| Language    | ISO Prolog             | ECMA Script     | Lua             |
| Paradigm    | 🎓 Logic               | Object-oriented | Object-oriented |
| Go API      | 😻 `database/sql`-like | original        | original        |
| Declarative | ✅                     | ❌              | ❌              |
| Sandboxing  | ✅                     | ❌              | ✅              |

## Getting started

### Install latest version

```console
go get -u github.com/ichiban/prolog
```

### Usage

#### Instantiate an interpreter

```go
p := prolog.New(os.Stdin, os.Stdout) // Or `prolog.New(nil, nil)` if you don't need user_input/user_output.
```

Or, if you want a sandbox interpreter without any built-in predicates:

```go
// See examples/sandboxing/main.go for details.
p := new(prolog.Interpreter)
```

#### Load a Prolog program

```go
if err := p.Exec(`
	human(socrates).       % This is a fact.
	mortal(X) :- human(X). % This is a rule.
`); err != nil {
	panic(err)
}
```

Similar to `database/sql`, you can use placeholder `?` to insert Go data as Prolog data.

```go
if err := p.Exec(`human(?).`, "socrates"); err != nil { // Same as p.Exec(`human("socrates").`)
	panic(err)
}
```

#### Run the Prolog program

```go
sols, err := p.Query(`mortal(?).`, "socrates") // Same as p.Query(`mortal("socrates").`)
if err != nil {
	panic(err)
}
defer sols.Close()

// Iterates over solutions.
for sols.Next() {
	fmt.Printf("Yes.\n") // ==> Yes.
}

// Check if an error occurred while querying.
if err := sols.Err(); err != nil {
	panic(err)
}
```

Or, if you want to query for the variable values for each solution:

```go
sols, err := p.Query(`mortal(Who).`)
if err != nil {
	panic(err)
}
defer sols.Close()

// Iterates over solutions.
for sols.Next() {
	// Prepare a struct with fields which name corresponds with a variable in the query.
	var s struct {
		Who string
	}
	if err := sols.Scan(&s); err != nil {
		panic(err)
	}
	fmt.Printf("Who = %s\n", s.Who) // ==> Who = socrates
}

// Check if an error occurred while querying.
if err := sols.Err(); err != nil {
	panic(err)
}
```

## The Default Language

`ichiban/prolog` adheres the ISO standard and comes with the ISO predicates as well as the Prologue for Prolog and DCG predicates.

See [the Wiki](https://github.com/ichiban/prolog/wiki) for the directives and the built-in predicates.

### Top Level

`1pl` is an experimental top level command for testing the default language and its compliance to the ISO standard.

You can install it with `go install`:

```console
go install github.com/ichiban/prolog/cmd/1pl@latest
```

Then, you can enter the top level with `1pl`:

```console
$(go env GOPATH)/bin/1pl [<file>...]
```

## Extensions

- **[predicates](https://github.com/guregu/predicates):** Native predicates for ichiban/prolog.
- **[kagomelog](https://github.com/ichiban/kagomelog):** a Japanese morphological analyzing predicate.

## License

Distributed under the MIT license. See `LICENSE` for more information.

## Contributing

See `ARCHITECTURE.md` for architecture details.

1. Fork it (https://github.com/ichiban/prolog/fork)
2. Create your feature branch (git checkout -b feature/fooBar)
3. Commit your changes (git commit -am 'Add some fooBar')
4. Push to the branch (git push origin feature/fooBar)
5. Create a new Pull Request

## Acknowledgments

We would like to extend our thanks to the following individuals for their contributions to this project:

- [guregu](https://github.com/guregu) for contributing code and ideas
- [Markus Triska](https://github.com/triska) for his deep knowledge and insights on modern Prolog, as evidenced by his insightful comments on issues
- [Prof. Ulrich Neumerkel](https://github.com/UWN) for valuable guidance, his [works on ISO standards](http://www.complang.tuwien.ac.at/ulrich/iso-prolog/), [the Prologue for Prolog](http://www.complang.tuwien.ac.at/ulrich/iso-prolog/prologue), and DCGs.

We are grateful for the support and contributions of everyone involved in this project. Arigatou gozaimasu!


prolog

Purl
====

Scripting in Go - it's Perl, but fluffy like a :cat:

- Embedded Perl 5.20.1
- Call native Go functions via XS
- Evaluates any Perl code with persistent state

Thanks to [Campher](https://github.com/bradfitz/campher) for a pointer in the right direction :smirk:

### Building purl

- `make`
- `./purl`

### Licence

Copyright ©‎ 2014, Ian Kent (http://iankent.uk).

Released under MIT license, see [LICENSE](LICENSE.md) for details.


purl

Go implementation of Starlark: Python-like language with deterministic evaluation and hermetic execution

# Starlark in Go

[![Go Tests](https://github.com/google/starlark-go/actions/workflows/tests.yml/badge.svg)](https://github.com/google/starlark-go/actions/workflows/tests.yml)
[![Go Reference](https://pkg.go.dev/badge/go.starlark.net/starlark.svg)](https://pkg.go.dev/go.starlark.net/starlark)

This is the home of the _Starlark in Go_ project.
Starlark in Go is an interpreter for Starlark, implemented in Go.
Starlark was formerly known as Skylark.
The import path for the Go package is `"go.starlark.net/starlark"`.

Starlark is a dialect of Python intended for use as a configuration language.
Like Python, it is an untyped dynamic language with high-level data
types, first-class functions with lexical scope, and garbage collection.
Unlike CPython, independent Starlark threads execute in parallel, so
Starlark workloads scale well on parallel machines.
Starlark is a small and simple language with a familiar and highly
readable syntax. You can use it as an expressive notation for
structured data, defining functions to eliminate repetition, or you
can use it to add scripting capabilities to an existing application.

A Starlark interpreter is typically embedded within a larger
application, and the application may define additional domain-specific
functions and data types beyond those provided by the core language.
For example, Starlark was originally developed for the
[Bazel build tool](https://bazel.build).
Bazel uses Starlark as the notation both for its BUILD files (like
Makefiles, these declare the executables, libraries, and tests in a
directory) and for [its macro
language](https://docs.bazel.build/versions/master/skylark/language.html),
through which Bazel is extended with custom logic to support new
languages and compilers.


## Documentation

* Language definition: [doc/spec.md](doc/spec.md)

* About the Go implementation: [doc/impl.md](doc/impl.md)

* API documentation: [pkg.go.dev/go.starlark.net/starlark](https://pkg.go.dev/go.starlark.net/starlark)

* Mailing list: [starlark-go](https://groups.google.com/forum/#!forum/starlark-go)

* Issue tracker: [https://github.com/google/starlark-go/issues](https://github.com/google/starlark-go/issues)

### Getting started

Build the code:

```shell
# check out the code and dependencies,
# and install interpreter in $GOPATH/bin
$ go install go.starlark.net/cmd/starlark@latest
```

Run the interpreter:

```console
$ cat coins.star
coins = {
  'dime': 10,
  'nickel': 5,
  'penny': 1,
  'quarter': 25,
}
print('By name:\t' + ', '.join(sorted(coins.keys())))
print('By value:\t' + ', '.join(sorted(coins.keys(), key=coins.get)))

$ starlark coins.star
By name:	dime, nickel, penny, quarter
By value:	penny, nickel, dime, quarter
```

Interact with the read-eval-print loop (REPL):

```pycon
$ starlark
>>> def fibonacci(n):
...    res = list(range(n))
...    for i in res[2:]:
...        res[i] = res[i-2] + res[i-1]
...    return res
...
>>> fibonacci(10)
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
>>>
```

When you have finished, type `Ctrl-D` to close the REPL's input stream.

Embed the interpreter in your Go program:

```go
import "go.starlark.net/starlark"

// Execute Starlark program in a file.
thread := &starlark.Thread{Name: "my thread"}
globals, err := starlark.ExecFile(thread, "fibonacci.star", nil, nil)
if err != nil { ... }

// Retrieve a module global.
fibonacci := globals["fibonacci"]

// Call Starlark function from Go.
v, err := starlark.Call(thread, fibonacci, starlark.Tuple{starlark.MakeInt(10)}, nil)
if err != nil { ... }
fmt.Printf("fibonacci(10) = %v\n", v) // fibonacci(10) = [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
```

See [starlark/example_test.go](starlark/example_test.go) for more examples.

### Contributing

We welcome submissions but please let us know what you're working on
if you want to change or add to the Starlark repository.

Before undertaking to write something new for the Starlark project,
please file an issue or claim an existing issue.
All significant changes to the language or to the interpreter's Go
API must be discussed before they can be accepted.
This gives all participants a chance to validate the design and to
avoid duplication of effort.

Despite some differences, the Go implementation of Starlark strives to
match the behavior of [the Java implementation](https://github.com/bazelbuild/bazel)
used by Bazel and maintained by the Bazel team.
For that reason, proposals to change the language itself should
generally be directed to [the Starlark site](
https://github.com/bazelbuild/starlark/), not to the maintainers of this
project.
Only once there is consensus that a language change is desirable may
its Go implementation proceed.

We use GitHub pull requests for contributions.

Please complete Google's contributor license agreement (CLA) before
sending your first change to the project.  If you are the copyright
holder, you will need to agree to the
[individual contributor license agreement](https://cla.developers.google.com/about/google-individual),
which can be completed online.
If your organization is the copyright holder, the organization will
need to agree to the [corporate contributor license agreement](https://cla.developers.google.com/about/google-corporate).
If the copyright holder for your contribution has already completed
the agreement in connection with another Google open source project,
it does not need to be completed again.

### Stability

We reserve the right to make breaking language and API changes at this
stage in the project, although we will endeavor to keep them to a minimum.
Once the Bazel team has finalized the version 1 language specification,
we will be more rigorous with interface stability.

We aim to support the most recent two (go1.x) releases of the Go
toolchain. For example, if the latest release is go1.26, we support it
along with go1.25, but not go1.24. This mirrors the support window of
the golang.org/x modules we depend upon. It is impractical to support
older versions.

### Credits

Starlark was designed and implemented in Java by
Jon Brandvein,
Alan Donovan,
Laurent Le Brun,
Dmitry Lomov,
Vladimir Moskva,
François-René Rideau,
Gergely Svigruha, and
Florian Weikert,
standing on the shoulders of the Python community.
The Go implementation was written by Alan Donovan and Jay Conrod;
its scanner was derived from one written by Russ Cox.

### Legal

Starlark in Go is Copyright (c) 2018 The Bazel Authors.
All rights reserved.

It is provided under a 3-clause BSD license:
[LICENSE](https://github.com/google/starlark-go/blob/master/LICENSE).

Starlark in Go is not an official Google product.

starlark-go

Go wrapper for [starlark-go](https://github.com/google/starlark-go) that simplifies script execution, offers data conversion, and useful Starlark libraries and extensions

# :sparkles: Starlet - Supercharging Starlark, Simply

[![godoc](https://pkg.go.dev/badge/github.com/1set/starlet.svg)](https://pkg.go.dev/github.com/1set/starlet)
[![codecov](https://codecov.io/github/1set/starlet/branch/master/graph/badge.svg?token=M1tauam4Hw)](https://codecov.io/github/1set/starlet)
[![codacy](https://app.codacy.com/project/badge/Grade/4e9c3f67a9574e6caa1b0d4706535815)](https://app.codacy.com/gh/1set/starlet/dashboard?utm_source=gh&utm_medium=referral&utm_content=&utm_campaign=Badge_grade)
[![codeclimate](https://api.codeclimate.com/v1/badges/290ec0cc3261d16c423f/maintainability)](https://codeclimate.com/github/1set/starlet/maintainability)
[![goreportcard](https://goreportcard.com/badge/github.com/1set/starlet)](https://goreportcard.com/report/github.com/1set/starlet)

> Enhancing your Starlark scripting experience with powerful extensions and enriched wrappers. Start your Starlark journey with Starlet, where simplicity meets functionality.

*Starlet* is yet another Go wrapper for the official [*Starlark in Go*](https://github.com/google/starlark-go) project, designed to enhance the Starlark scripting experience with powerful extensions and enriched wrappers, and provide a more user-friendly and powerful interface for embedding Starlark scripting in your Go applications.

Inspired by the [*Starlight*](https://github.com/starlight-go/starlight) and [*Starlib*](https://github.com/qri-io/starlib) projects, *Starlet* focuses on three main objectives: providing an easier-to-use **Go wrapper** for Starlark, offering flexible **data conversion** between Go and Starlark, and supplying a set of **useful libraries** for Starlark.

## Key Features

*Starlet* provides the following key features:

### Flexible Machine Abstraction

*Starlet* introduces a streamlined interface for executing Starlark scripts, encapsulating the complexities of setting up and running the scripts: The [`Machine`](https://pkg.go.dev/github.com/1set/starlet#Machine) type serves as a comprehensive wrapper for Starlark runtime environments, offering an intuitive API for executing Starlark scripts, managing global variables, loading modules, controlling the script execution flow., and handling script outputs.

### Enhanced Data Conversion

*Starlet* offers the [`dataconv`](https://pkg.go.dev/github.com/1set/starlet/dataconv) package that simplifies the data exchange between Go and Starlark types. Unlike *Starlight*, which wraps Go values in Starlark-friendly structures, it focuses on transforming Go values into their Starlark equivalents and vice versa. This allows for a more seamless integration of Go's rich data types into Starlark scripts.

### Extended Libraries & Functionalities

*Starlet* includes a set of custom modules and libraries that extend the functionality of the Starlark language. These modules cover a wide range of use cases, such as file manipulation, HTTP client, JSON/CSV handling, and more, making Starlark scripts even more powerful and versatile.

## Libraries

*Starlet* comes with a set of libraries to extend the standard Starlark library. Here's a brief overview:

| Package                           | Go Doc                                                                                                                                       | Description                                                   |
|:----------------------------------|:---------------------------------------------------------------------------------------------------------------------------------------------|:--------------------------------------------------------------|
| [`atom`](/lib/atom)               | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/atom.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/atom)               | Atomic operations for integers, floats, and strings           |
| [`base64`](/lib/base64)           | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/base64.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/base64)           | Base64 encoding & decoding functions                          |
| [`csv`](/lib/csv)                 | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/csv.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/csv)                 | Parses and writes comma-separated values (csv) contents       |
| [`file`](/lib/file)               | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/file.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/file)               | Functions to interact with the file system                    |
| [`goidiomatic`](/lib/goidiomatic) | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/goidiomatic.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/goidiomatic) | Go idiomatic functions and values for Starlark                |
| [`hashlib`](/lib/hashlib)         | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/hashlib.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/hashlib)         | Hash primitives for Starlark                                  |
| [`http`](/lib/http)               | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/http.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/http)               | HTTP client and server handler implementation for Starlark    |
| [`json`](/lib/json)               | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/json.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/json)               | Utilities for converting Starlark values to/from JSON strings |
| [`log`](/lib/log)                 | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/log.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/log)                 | Functionality for logging messages at various severity levels |
| [`path`](/lib/path)               | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/path.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/path)               | Functions to manipulate directories and file paths            |
| [`random`](/lib/random)           | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/random.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/random)           | Functions to generate random values for various distributions |
| [`re`](/lib/re)                   | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/re.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/re)                   | Regular expression functions for Starlark                     |
| [`runtime`](/lib/runtime)         | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/runtime.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/runtime)         | Provides Go and app runtime information                       |
| [`string`](/lib/string)           | [![godoc](https://pkg.go.dev/badge/github.com/1set/starlet/lib/string.svg)](https://pkg.go.dev/github.com/1set/starlet/lib/string)           | Constants and functions to manipulate strings                 |

For extensive documentation on each library, please refer to the respective README files in the [`lib`](/lib) directory. Additionally, *Starlet* includes an array of official modules. You can explore all provided modules by using [`GetAllBuiltinModuleNames()`](https://pkg.go.dev/github.com/1set/starlet#GetAllBuiltinModuleNames) method.

## Installation

To install *Starlet*, use the following Go command under your project directory:

```bash
go get github.com/1set/starlet
```

To explore the capabilities of the Starlet CLI tool, use the command below to install:

```bash
go install github.com/1set/starlet/cmd/starlet@latest
```

## Usage

You can use *Starlet* to enhance your Starlark scripting experience. Here's a quick example:

```go
import "github.com/1set/starlet"

// Define your machine with global variables and modules
globals := starlet.StringAnyMap{
    "greet": func(name string) string {
        return fmt.Sprintf("Hello, %s!", name)
    },
}
mac := starlet.NewWithNames(globals, []string{"random"}, nil)

// Run a Starlark script in the machine
script := `
target = random.choice(["World", "Starlark", "Starlet"])
text = greet(target)
print("Starlark:", text)
`
res, err := mac.RunScript([]byte(script), nil)

// Check for errors and results
if err != nil {
    fmt.Println("Error executing script:", err)
    return
}
fmt.Println("Go:", res["text"].(string))
fmt.Println("Modules:", starlet.GetAllBuiltinModuleNames())
```

This may output:

```
Starlark: Hello, Starlet!
Go: Hello, Starlet!
Modules: [atom base64 csv file go_idiomatic hashlib http json log math path random re runtime string struct time]
```

Use CLI to interact with the read-eval-print loop (REPL):

```python
>>> resp = http.get("https://api.github.com/repos/1set/starlet")
>>> resp.status_code
200
>>> data = resp.json()
>>> data["description"]
"✨ Enhancing your Starlark scripting experience with powerful extensions and enriched wrappers. Start your Starlark journey with Starlet, where simplicity meets functionality."
>>> ",".join(data["topics"])
"go,golang,script,scripting,scripting-language,starlark,starlark-go,starlark-lang,starlark-language,starlarky"
>>> pprint(data["license"])
{
    "key": "mit",
    "name": "MIT License",
    "node_id": "MDc6TGljZW5zZTEz",
    "spdx_id": "MIT",
    "url": "https://api.github.com/licenses/mit"
}
>>>
```

## Contributing

Contributions to *Starlet* are all welcomed. If you encounter any issues or have suggestions for improvements, please feel free to open an issue or submit a pull request. Before undertaking any significant changes, please let us know by filing an issue or claiming an existing one to ensure there is no duplication of effort.

## License

*Starlet* is licensed under the [MIT License](LICENSE).

## Credits

*Starlet* is inspired by two projects:

1. [Starlight](https://github.com/starlight-go/starlight): A Go wrapper and data conversion tool between Go and Starlark.
2. [Starlib](https://github.com/qri-io/starlib): A collection of third-party libraries for Starlark.

We appreciate the work done by the creators and contributors of these projects. Their efforts have paved the way for the development of *Starlet*. Special thanks to the authors and contributors of these projects! 🎉


starlet

# The Tengo Language

[![GoDoc](https://godoc.org/github.com/d5/tengo/v2?status.svg)](https://godoc.org/github.com/d5/tengo/v2)
![test](https://github.com/d5/tengo/workflows/test/badge.svg)
[![Go Report Card](https://goreportcard.com/badge/github.com/d5/tengo)](https://goreportcard.com/report/github.com/d5/tengo)

**Tengo is a small, dynamic, fast, secure script language for Go.** 

Tengo is **[fast](#benchmark)** and secure because it's compiled/executed as
bytecode on stack-based VM that's written in native Go.

```golang
/* The Tengo Language */
fmt := import("fmt")

each := func(seq, fn) {
    for x in seq { fn(x) }
}

sum := func(init, seq) {
    each(seq, func(x) { init += x })
    return init
}

fmt.println(sum(0, [1, 2, 3]))   // "6"
fmt.println(sum("", [1, 2, 3]))  // "123"
```

> Test this Tengo code in the
> [Tengo Playground](https://tengolang.com/?s=0c8d5d0d88f2795a7093d7f35ae12c3afa17bea3)

## Features

- Simple and highly readable
  [Syntax](https://github.com/d5/tengo/blob/master/docs/tutorial.md)
  - Dynamic typing with type coercion
  - Higher-order functions and closures
  - Immutable values
- [Securely Embeddable](https://github.com/d5/tengo/blob/master/docs/interoperability.md)
  and [Extensible](https://github.com/d5/tengo/blob/master/docs/objects.md)
- Compiler/runtime written in native Go _(no external deps or cgo)_
- Executable as a
  [standalone](https://github.com/d5/tengo/blob/master/docs/tengo-cli.md)
  language / REPL
- Use cases: rules engine, [state machine](https://github.com/d5/go-fsm),
  data pipeline, [transpiler](https://github.com/d5/tengo2lua)

## Benchmark

| | fib(35) | fibt(35) |  Language (Type)  |
| :--- |    ---: |     ---: |  :---: |
| [**Tengo**](https://github.com/d5/tengo) | `2,315ms` | `3ms` | Tengo (VM) |
| [go-lua](https://github.com/Shopify/go-lua) | `4,028ms` | `3ms` | Lua (VM) |
| [GopherLua](https://github.com/yuin/gopher-lua) | `4,409ms` | `3ms` | Lua (VM) |
| [goja](https://github.com/dop251/goja) | `5,194ms` | `4ms` | JavaScript (VM) |
| [starlark-go](https://github.com/google/starlark-go) | `6,954ms` | `3ms` | Starlark (Interpreter) |
| [gpython](https://github.com/go-python/gpython) | `11,324ms` | `4ms` | Python (Interpreter) |
| [Yaegi](https://github.com/containous/yaegi) | `11,715ms` | `10ms` | Yaegi (Interpreter) |
| [otto](https://github.com/robertkrimen/otto) | `48,539ms` | `6ms` | JavaScript (Interpreter) |
| [Anko](https://github.com/mattn/anko) | `52,821ms` | `6ms` | Anko (Interpreter) |
| - | - | - | - |
| Go | `47ms` | `2ms` | Go (Native) |
| Lua | `756ms` | `2ms` | Lua (Native) |
| Python | `1,907ms` | `14ms` | Python2 (Native) |

_* [fib(35)](https://github.com/d5/tengobench/blob/master/code/fib.tengo):
Fibonacci(35)_  
_* [fibt(35)](https://github.com/d5/tengobench/blob/master/code/fibtc.tengo):
[tail-call](https://en.wikipedia.org/wiki/Tail_call) version of Fibonacci(35)_  
_* **Go** does not read the source code from file, while all other cases do_  
_* See [here](https://github.com/d5/tengobench) for commands/codes used_

## Quick Start

```
go get github.com/d5/tengo/v2
```

A simple Go example code that compiles/runs Tengo script code with some input/output values:

```golang
package main

import (
	"context"
	"fmt"

	"github.com/d5/tengo/v2"
)

func main() {
	// create a new Script instance
	script := tengo.NewScript([]byte(
`each := func(seq, fn) {
    for x in seq { fn(x) }
}

sum := 0
mul := 1
each([a, b, c, d], func(x) {
    sum += x
    mul *= x
})`))

	// set values
	_ = script.Add("a", 1)
	_ = script.Add("b", 9)
	_ = script.Add("c", 8)
	_ = script.Add("d", 4)

	// run the script
	compiled, err := script.RunContext(context.Background())
	if err != nil {
		panic(err)
	}

	// retrieve values
	sum := compiled.Get("sum")
	mul := compiled.Get("mul")
	fmt.Println(sum, mul) // "22 288"
}
```

Or, if you need to evaluate a simple expression, you can use [Eval](https://pkg.go.dev/github.com/d5/tengo/v2#Eval) function instead:


```golang
res, err := tengo.Eval(ctx,
	`input ? "success" : "fail"`,
	map[string]interface{}{"input": 1})
if err != nil {
	panic(err)
}
fmt.Println(res) // "success"
```

## References

- [Language Syntax](https://github.com/d5/tengo/blob/master/docs/tutorial.md)
- [Object Types](https://github.com/d5/tengo/blob/master/docs/objects.md)
- [Runtime Types](https://github.com/d5/tengo/blob/master/docs/runtime-types.md)
  and [Operators](https://github.com/d5/tengo/blob/master/docs/operators.md)
- [Builtin Functions](https://github.com/d5/tengo/blob/master/docs/builtins.md)
- [Interoperability](https://github.com/d5/tengo/blob/master/docs/interoperability.md)
- [Tengo CLI](https://github.com/d5/tengo/blob/master/docs/tengo-cli.md)
- [Standard Library](https://github.com/d5/tengo/blob/master/docs/stdlib.md)
- Syntax Highlighters: [VSCode](https://github.com/lissein/vscode-tengo), [Atom](https://github.com/d5/tengo-atom), [Vim](https://github.com/geseq/tengo-vim), [Emacs](https://github.com/CsBigDataHub/tengo-mode)
- **Why the name Tengo?** It's from [1Q84](https://en.wikipedia.org/wiki/1Q84).




tengo

The Wa Programming Language embedded in Go

<div align="center">
<h1>The Wa Programming Language</h1>

[简体中文](https://github.com/wa-lang/wa/blob/master/README-zh.md) | [English](https://github.com/wa-lang/wa/blob/master/README.md) 


</div>
<div align="center">

[![](https://img.shields.io/badge/Wa-WASM-green?logo=data%3Aimage%2Fsvg%2Bxml%3Bcharset%3Dutf-8%3Bbase64%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%2BCiAgPHBhdGggZD0iTTUwIDU1QzUyLjc2MTQgNTUgNTUgNTIuNzYxNCA1NSA1MEM1NSA0Ny4yMzg2IDUyLjc2MTQgNDUgNTAgNDVDNDcuMjM4NiA0NSA0NSA0Ny4yMzg2IDQ1IDUwQzQ1IDUyLjc2MTQgNDcuMjM4NiA1NSA1MCA1NVoiIGZpbGw9IndoaXRlIi8%2BCiAgPHBhdGggZD0iTTI1MCA1NUMyNTIuNzYxIDU1IDI1NSA1Mi43NjE0IDI1NSA1MEMyNTUgNDcuMjM4NiAyNTIuNzYxIDQ1IDI1MCA0NUMyNDcuMjM5IDQ1IDI0NSA0Ny4yMzg2IDI0NSA1MEMyNDUgNTIuNzYxNCAyNDcuMjM5IDU1IDI1MCA1NVoiIGZpbGw9IndoaXRlIi8%2BCiAgPHBhdGggZD0iTTE1MCAxODBMMTg0IDIxNEwyMTggMTgwTTE1MCAxODBMMTE2IDIxNEw4MiAxODAiIGZpbGw9Im5vbmUiIHN0cm9rZT0id2hpdGUiIHN0cm9rZS13aWR0aD0iOCIgc3Ryb2tlLWxpbmVjYXA9InJvdW5kIi8%2BCjwvc3ZnPgo%3D)](https://wa-lang.org)
[![Build Status](https://github.com/wa-lang/wa/actions/workflows/wa.yml/badge.svg)](https://github.com/wa-lang/wa/actions/workflows/wa.yml)
[![Coverage Status](https://coveralls.io/repos/github/wa-lang/wa/badge.svg)](https://coveralls.io/github/wa-lang/wa)
[![GitHub release](https://img.shields.io/github/v/tag/wa-lang/wa.svg?label=release)](https://github.com/wa-lang/wa/releases)
[![license](https://img.shields.io/github/license/wa-lang/wa.svg)](https://github.com/wa-lang/wa/blob/master/LICENSE)
[![CNCF Landscape](https://img.shields.io/badge/CNCF%20Landscape-5699C6)](https://landscape.cncf.io/?item=wasm--languages--wa-lang)

</div>

Wa (Chinese name "凹", which pronounced "Wa") is a general-purpose programming language designed for for WebAssembly. The goal is to provide a simple, reliable, easy-to-use, statically typed language for high-performance web applications. The code generator and runtime are fully independently developed (not dependent on external projects such as LLVM). Currently, Wa is in the engineering trial stage.

![](docs/images/wa-chan/wa-chan-front-small-logo-animate1.svg)

- Home: [https://wa-lang.github.io/](https://wa-lang.github.io/)
- Manual: [https://wa-lang.github.io/man/en/](https://wa-lang.github.io/man/en/)
- Github: [https://github.com/wa-lang/wa](https://github.com/wa-lang/wa)
- Playground: [https://wa-lang.org/playground](https://wa-lang.org/playground)

> Note: The Wa compiler source files are distributed under the AGPL-v3 license. The Wa standard library is licensed under the MIT license. The programs you develop using the Wa language can be safely used commercially without open source. If you want to integrate the Wa compiler code into your own project, but do not want to be restricted by the infectiousness of AGPL-v3, you can contact us to customize the license agreement for you.

## How to contribute
The project is still in the prototype stage. If you have co-construction or PR needs, please refer to [How to contribute](./wca/readme_en.md). We no longer accept PRs for modifications to third-party libraries.

> Note: Our canonical Git repository is located at https://gitcode.com/wa-lang/wa. There is a mirror of the repository at https://github.com/wa-lang/wa.

> Note: Submitting a PR to this repository is deemed to be your recognition and acceptance of the [Wa Contributor Agreement](./wca/wca.md)(Aka WCA), but your PRs will not be reviewed or accepted until WCA is actually signed.

## Wa Language Compiler Architecture

Wa is designed with a dual-frontend system (supporting both Chinese and English syntax) that interfaces with a unified Intermediate Representation (Wa-lang IR). The backend connects to proprietary Chinese/English assemblers, targeting various Instruction Set Architectures (ISA). This design achieves a fully self-developed toolchain without external dependencies such as GCC or LLVM.


```mermaid
graph LR
    wa_ext(Wa English.wa);
    wz_ext(Wa Chinese.wz);

    wa_ast(Wa English AST);
    wz_ast(Wa Chinese AST);
    
    wair(Wa-IR);

    wasm(WASM);
    nasm(Wa Native Assembler);
    c_cpp(C/C++);

    x64(X64);
    loong64(LoongArch);
    riscv(RISCV);
    arm64(ARM64);

    wa_ext --> wa_ast;
    wz_ext --> wz_ast;

    wa_ast --> wair;
    wz_ast --> wair;

    wair --> wasm
    wair --> nasm
    wair --> c_cpp

    nasm --> loong64
    nasm --> x64
    nasm --> riscv
    nasm --> arm64
```

- Note: The RISC-V platform has not yet undergone hardware testing due to the lack of a physical environment.
- Note: The Wa-lang IR is currently being refined; WebAssembly (Wasm) is presently utilized as the intermediate IR.

## Playground

[https://wa-lang.org/playground](https://wa-lang.org/playground)

![](docs/images/playground-01.png)

## Snake Game

- Play: [https://wa-lang.org/wa/snake/](https://wa-lang.org/wa/snake/)
- Code: [waroot/examples/snake/README-en.md](waroot/examples/snake/README-en.md)

![](docs/images/snake-01.jpg)

## WASM4 Game

- Wasm4/Snake: https://wa-lang.org/wa/w4-snake/
  - Source Code (English): https://github.com/wa-lang/wa/tree/master/waroot/examples/w4-snake/
  - Source Code (Chinese): https://github.com/wa-lang/wa/tree/master/waroot/examples/w4-snake-wz/
- Wasm4/2048: https://wa-lang.org/wa/w4-2048/

![](docs/images/wasm4-game-snake-2048.png)

- [Wasm4/Snake Code](waroot/examples/w4-snake)
- [Wasm4/2048 Code](waroot/examples/w4-2048)

## NES emulator

- Play: [https://wa-lang.org/nes/](https://wa-lang.org/nes/)
- Code: [https://github.com/wa-lang/nes](https://github.com/wa-lang/nes)

![](docs/images/nes-01.png)

## WebGPU Demo

- Play: [https://wa-lang.org/webgpu/](https://wa-lang.org/webgpu/)
- Code: [https://github.com/wa-lang/webgpu](https://github.com/wa-lang/webgpu)

![](docs/images/webgpu-01.png)

## P5 for creative coding

- https://wa-lang.org/smalltalk/st0037.html

![](docs/images/p5wa-01.png)

## Arduino Nano 33

- https://wa-lang.org/smalltalk/st0052.html

![](docs/images/arduino-nano33-01.png)


## Example: Print (Chinese)

Print string and call function：

```wz
注: 你好，世界！

引入 "书"

函数·主控:
	书·说("你好，凹语言中文版！")
完毕
```

Execute the program:

```
$ wa run hello.wz 
你好，凹语言中文版！
```

## Example: Print (English)

Print rune and call function：

```wa
import "fmt"

global year: i32 = 2023

func main {
	println("hello, Wa!")
	println(add(40, 2), year)

	fmt.Println(1+1)
}

func add(a: i32, b: i32) => i32 {
	return a+b
}
```

Execute the program:

```
$ wa run hello.wa 
hello, Wa!
42 2023
2
```

## Example: Print Prime

Print prime numbers up to 30:

```wa
func main {
	for n := 2; n <= 30; n = n + 1 {
		isPrime: int = 1
		for i := 2; i*i <= n; i = i + 1 {
			if x := n % i; x == 0 {
				isPrime = 0
			}
		}
		if isPrime != 0 {
			println(n)
		}
	}
}
```

Execute the program:

```
$ cd waroot && wa run examples/prime
2
3
5
7
11
13
17
19
23
29
```

More examples [waroot/examples](waroot/examples)

## Contributors

|Contributor|Contribution points|
| --- | --- |
|柴树杉| 124650|
|丁尔男| 116650|
|史斌  | 10000|
|扈梦明| 72500|
|赵普明| 10000|
|宋汝阳|  2000|
|刘云峰|  1000|
|王潇南|  1000|
|王泽龙|  1000|
|吴烜  |  3000|
|刘斌  |  2500|
|尹贻浩|  2000|
|安博超 | 3000|
|yuqiaoyu| 600|
|qstesiro| 200|
|small_broken_gong|100|
|tk103331|100|
|蔡兴|3000|
|王任义|1000|
|imalasong|2000|
|杨刚|4000|
|崔爽|2000|
|李瑾|20000|
|王委委|100|
|雪碧|100|

## Contact us

Email: `dev{AT}wa-lang.org`


Wa/凹语言

Cross-platform Polyglot Runtime which supports NodeJS, JavaScript, TypeScript, Python, Ruby, C#, WebAssembly, Java, Cobol and more

<div align="center">
  <a href="https://metacall.io" target="_blank"><img src="https://raw.githubusercontent.com/metacall/core/develop/deploy/images/logo.png" alt="METACALL" style="max-width:100%; margin: 0 auto;" width="80" height="80"></a>
  <h1><b>MetaCall Polyglot Runtime</b></h1>
  <a href="https://metacall.io">MetaCall.io</a> |
  <a href="#install">Install</a> |
  <a href="https://github.com/metacall/core/blob/develop/docs/README.md">Docs</a>
</div>
<div id="badges" align="center">
  <a href="https://t.me/joinchat/BMSVbBatp0Vi4s5l4VgUgg" alt="Discord">
    <img src="https://img.shields.io/static/v1?label=metacall&message=join&color=blue&logo=telegram&style=flat" /></a>

  <a href="https://discord.gg/upwP4mwJWa" alt="Discord">
    <img src="https://img.shields.io/discord/781987805974757426?label=discord&style=flat" /></a>

  <a href="https://matrix.to/#/#metacall:matrix.org" alt="Matrix">
    <img src="https://img.shields.io/matrix/metacall:matrix.org?label=matrix&style=flat" /></a>

  <a href="https://twitter.com/metacallio" alt="Twitter">
    <img src="https://img.shields.io/twitter/follow/metacallio?label=MetaCall" /></a>

  <a href="https://medium.com/@metacall/call-functions-methods-or-procedures-between-programming-languages-with-metacall-58cfece35d7" target="_blank"><img src="https://raw.githubusercontent.com/metacall/core/develop/deploy/images/overview.png" alt="M E T A C A L L" style="max-width:100%; margin: 0 auto;" width="350" height="auto"></a>
</div>

**MetaCall** allows calling functions, methods or procedures between multiple programming languages.

`sum.py`
``` python
def sum(a, b):
  return a + b
```

`main.js`
``` javascript
const { sum } = require('./sum.py');

sum(3, 4); // 7
```

`shell`
``` sh
metacall main.js
```

**MetaCall** is an extensible, embeddable, and interoperable cross-platform polyglot runtime. It supports NodeJS, Vanilla JavaScript, TypeScript, Python, Ruby, C#, Java, WASM, Go, C, C++, Rust, D, Cobol [and more](https://github.com/metacall/core/blob/develop/docs/README.md#2-language-support).

## Install

The easiest way to install **MetaCall** is the following:

``` sh
curl -sL https://raw.githubusercontent.com/metacall/install/master/install.sh | sh
```

For more information about other install methodologies and platforms or Docker, check the [install documentation](https://github.com/metacall/core/blob/develop/docs/README.md#41-installation).

## Examples

You can find a complete [list of examples in the documentation](https://github.com/metacall/core/blob/develop/docs/README.md#43-examples). If you are interested in submitting new examples, please [contact us in our chats](#badges).


metacall

PHP embedded in Go, with a `net/http` handler

# FrankenPHP: Modern App Server for PHP

<h1 align="center"><a href="https://frankenphp.dev"><img src="frankenphp.png" alt="FrankenPHP" width="600"></a></h1>

FrankenPHP is a modern application server for PHP built on top of the [Caddy](https://caddyserver.com/) web server.

FrankenPHP gives superpowers to your PHP apps thanks to its stunning features: [_Early Hints_](https://frankenphp.dev/docs/early-hints/), [worker mode](https://frankenphp.dev/docs/worker/), [real-time capabilities](https://frankenphp.dev/docs/mercure/), [hot reloading](https://frankenphp.dev/docs/hot-reload/), automatic HTTPS, HTTP/2, and HTTP/3 support...

FrankenPHP works with any PHP app and makes your Laravel and Symfony projects faster than ever thanks to their official integrations with the worker mode.

FrankenPHP can also be used as a standalone Go library to embed PHP in any app using `net/http`.

[**Learn more** on _frankenphp.dev_](https://frankenphp.dev) and in this slide deck:

<a href="https://dunglas.dev/2022/10/frankenphp-the-modern-php-app-server-written-in-go/"><img src="https://dunglas.dev/wp-content/uploads/2022/10/frankenphp.png" alt="Slides" width="600"></a>

## Getting Started

### Install Script

On Linux and macOS, copy this line into your terminal to automatically
install an appropriate version for your platform:

```console
curl https://frankenphp.dev/install.sh | sh
```

On Windows, run this in PowerShell:

```powershell
irm https://frankenphp.dev/install.ps1 | iex
```

### Standalone Binary

We provide FrankenPHP binaries for Linux, macOS and Windows
containing [PHP 8.5](https://www.php.net/releases/8.5/).

Linux binaries are statically linked, so they can be used on any Linux distribution without installing any dependency. macOS binaries are also self-contained.
They contain most popular PHP extensions.
Windows archives contain the official PHP binary for Windows.

[Download FrankenPHP](https://github.com/php/frankenphp/releases)

### rpm Packages

Our maintainers offer rpm packages for all systems using `dnf`. To install, run:

```console
sudo dnf install https://rpm.henderkes.com/static-php-1-0.noarch.rpm
sudo dnf module enable php-zts:static-8.5 # 8.2-8.5 available
sudo dnf install frankenphp
```

**Installing extensions:** `sudo dnf install php-zts-<extension>`

For extensions not available by default, use [PIE](https://github.com/php/pie):

```console
sudo dnf install pie-zts
sudo pie-zts install asgrim/example-pie-extension
```

### deb Packages

Our maintainers offer deb packages for all systems using `apt`. To install, run:

```console
VERSION=85 # 82-85 available
sudo curl https://pkg.henderkes.com/api/packages/${VERSION}/debian/repository.key -o /etc/apt/keyrings/static-php${VERSION}.asc
echo "deb [signed-by=/etc/apt/keyrings/static-php${VERSION}.asc] https://pkg.henderkes.com/api/packages/${VERSION}/debian php-zts main" | sudo tee -a /etc/apt/sources.list.d/static-php${VERSION}.list
sudo apt update
sudo apt install frankenphp
```

**Installing extensions:** `sudo apt install php-zts-<extension>`

For extensions not available by default, use [PIE](https://github.com/php/pie):

```console
sudo apt install pie-zts
sudo pie-zts install asgrim/example-pie-extension
```

### apk Packages

Our maintainers offer apk packages for all systems using `apk`. To install, run:

```console
VERSION=85 # 82-85 available
echo "https://pkg.henderkes.com/api/packages/${VERSION}/alpine/main/php-zts" | sudo tee -a /etc/apk/repositories
KEYFILE=$(curl -sJOw '%{filename_effective}' https://pkg.henderkes.com/api/packages/${VERSION}/alpine/key)
sudo mv ${KEYFILE} /etc/apk/keys/ &&
sudo apk update &&
sudo apk add frankenphp
```

**Installing extensions:** `sudo apk add php-zts-<extension>`

For extensions not available by default, use [PIE](https://github.com/php/pie):

```console
sudo apk add pie-zts
sudo pie-zts install asgrim/example-pie-extension
```

### Homebrew

FrankenPHP is also available as a [Homebrew](https://brew.sh) package for macOS and Linux.

```console
brew install dunglas/frankenphp/frankenphp
```

**Installing extensions:** Use [PIE](https://github.com/php/pie).

### Usage

To serve the content of the current directory, run:

```console
frankenphp php-server
```

You can also run command-line scripts with:

```console
frankenphp php-cli /path/to/your/script.php
```

For the deb and rpm packages, you can also start the systemd service:

```console
sudo systemctl start frankenphp
```

### Docker

Alternatively, [Docker images](https://frankenphp.dev/docs/docker/) are available:

```console
docker run -v .:/app/public \
    -p 80:80 -p 443:443 -p 443:443/udp \
    dunglas/frankenphp
```

Go to `https://localhost`, and enjoy!

> [!TIP]
>
> Do not attempt to use `https://127.0.0.1`. Use `https://localhost` and accept the self-signed certificate.
> Use the [`SERVER_NAME` environment variable](docs/config.md#environment-variables) to change the domain to use.

## Docs

- [Classic mode](https://frankenphp.dev/docs/classic/)
- [Worker mode](https://frankenphp.dev/docs/worker/)
- [Early Hints support (103 HTTP status code)](https://frankenphp.dev/docs/early-hints/)
- [Real-time](https://frankenphp.dev/docs/mercure/)
- [Logging](https://frankenphp.dev/docs/logging/)
- [Hot reloading](https://frankenphp.dev/docs/hot-reload/)
- [Efficiently Serving Large Static Files](https://frankenphp.dev/docs/x-sendfile/)
- [Configuration](https://frankenphp.dev/docs/config/)
- [Writing PHP Extensions in Go](https://frankenphp.dev/docs/extensions/)
- [Docker images](https://frankenphp.dev/docs/docker/)
- [Deploy in production](https://frankenphp.dev/docs/production/)
- [Performance optimization](https://frankenphp.dev/docs/performance/)
- [Create **standalone**, self-executable PHP apps](https://frankenphp.dev/docs/embed/)
- [Create static binaries](https://frankenphp.dev/docs/static/)
- [Compile from sources](https://frankenphp.dev/docs/compile/)
- [Observability](https://frankenphp.dev/docs/observability/)
- [WordPress integration](https://frankenphp.dev/docs/wordpress/)
- [Symfony integration](https://frankenphp.dev/docs/symfony/)
- [Laravel integration](https://frankenphp.dev/docs/laravel/)
- [Known issues](https://frankenphp.dev/docs/known-issues/)
- [Demo app (Symfony) and benchmarks](https://github.com/dunglas/frankenphp-demo)
- [Go library documentation](https://pkg.go.dev/github.com/dunglas/frankenphp)
- [Contributing and debugging](https://frankenphp.dev/docs/contributing/)

## Examples and Skeletons

- [Symfony](https://frankenphp.dev/docs/symfony/)
- [API Platform](https://api-platform.com/docs/symfony)
- [Laravel](https://frankenphp.dev/docs/laravel/)
- [Sulu](https://sulu.io/blog/running-sulu-with-frankenphp)
- [WordPress](https://github.com/StephenMiracle/frankenwp)
- [Drupal](https://github.com/dunglas/frankenphp-drupal)
- [Joomla](https://github.com/alexandreelise/frankenphp-joomla)
- [TYPO3](https://github.com/ochorocho/franken-typo3)
- [Magento2](https://github.com/ekino/frankenphp-magento2)


FrankenPHP

gisp
====

Simple (non standard) compiler of Lisp/Scheme to Go.

## Includes
- Lexer based on Rob Pike's [Lexical Scanning in Go](http://cuddle.googlecode.com/hg/talk/lex.html#title-slide)
- Simple recursive parser, supporting ints, floats, strings, bools
- TCO via loop/recur
- AST generating REPL included


## Build and Run
```
> go build && ./gisp
>>
```
From here you can type in forms and you'll get the Go AST back.
To compile a file:
```
> ./gisp filename.gsp
````

# Functions
```
+, -, *, mod, let, if, ns, def, fn, all pre-existing Go functions
```
See [examples](examples) for some Project Euler solutions

# License

MIT


gisp

[![Build Status](https://circleci.com/gh/Shopify/go-lua.png?circle-token=997f951c602c0c63a263eba92975428a49ee4c2e)](https://circleci.com/gh/Shopify/go-lua)
[![GoDoc](https://godoc.org/github.com/Shopify/go-lua?status.png)](https://godoc.org/github.com/Shopify/go-lua)

A Lua VM in pure Go
===================

go-lua is a port of the Lua 5.2 VM to pure Go. It is compatible with binary files dumped by `luac`, from the [Lua reference implementation](http://www.lua.org/).

The motivation is to enable simple scripting of Go applications. For example, it is used to describe flows in [Shopify's](http://www.shopify.com/) load generation tool, Genghis.

Usage
-----

go-lua is intended to be used as a Go package. It does not include a command to run the interpreter. To start using the library, run:
```sh
go get github.com/Shopify/go-lua
```

To develop & test go-lua, you'll also need the [lua-tests](https://github.com/Shopify/lua-tests) submodule checked out:
```sh
git submodule update --init
```

You can then develop with the usual Go commands, e.g.:
```sh
go build
go test -cover
```

A simple example that loads & runs a Lua script is:
```go
package main

import "github.com/Shopify/go-lua"

func main() {
  l := lua.NewState()
  lua.OpenLibraries(l)
  if err := lua.DoFile(l, "hello.lua"); err != nil {
    panic(err)
  }
}
```

Status
------

go-lua has been used in production in Shopify's load generation tool, Genghis, since May 2014, and is also part of Shopify's resiliency tooling.

The core VM and compiler has been ported and tested. The compiler is able to correctly process all Lua source files from the [Lua test suite](https://github.com/Shopify/lua-tests). The VM has been tested to correctly execute over a third of the Lua test cases.

Most core Lua libraries are at least partially implemented. Prominent exceptions are regular expressions, coroutines and `string.dump`.

Weak reference tables are not and will not be supported. go-lua uses the Go heap for Lua objects, and Go does not support weak references.

Benchmarks
----------

Benchmark results shown here are taken from a Mid 2012 MacBook Pro Retina with a 2.6 GHz Core i7 CPU running OS X 10.10.2, go 1.4.2 and Lua 5.2.2.

The Fibonacci function can be written a few different ways to evaluate different performance characteristics of a language interpreter. The simplest way is as a recursive function:
```lua
  function fib(n)
    if n == 0 then
      return 0
    elseif n == 1 then
      return 1
    end
    return fib(n-1) + fib(n-2)
  end
```

This exercises the call stack implementation. When computing `fib(35)`, go-lua is about 6x slower than the C Lua interpreter. [Gopher-lua](https://github.com/yuin/gopher-lua) is about 20% faster than go-lua. Much of the performance difference between go-lua and gopher-lua comes from the inclusion of debug hooks in go-lua. The remainder is due to the call stack implementation - go-lua heap-allocates Lua stack frames with a separately allocated variant struct, as outlined above. Although it caches recently used stack frames, it is outperformed by the simpler statically allocated call stacks in gopher-lua.
```
  $ time lua fibr.lua
  real  0m2.807s
  user  0m2.795s
  sys   0m0.006s
  
  $ time glua fibr.lua
  real  0m14.528s
  user  0m14.513s
  sys   0m0.031s
  
  $ time go-lua fibr.lua
  real  0m17.411s
  user  0m17.514s
  sys   0m1.287s
```

The recursive Fibonacci function can be transformed into a tail-recursive variant:
```lua
  function fibt(n0, n1, c)
    if c == 0 then
      return n0
    else if c == 1 then
      return n1
    end
    return fibt(n1, n0+n1, c-1)
  end
  
  function fib(n)
    fibt(0, 1, n)
  end
```

The Lua interpreter detects and optimizes tail calls. This exhibits similar relative performance between the 3 interpreters, though gopher-lua edges ahead a little due to its simpler stack model and reduced bookkeeping.
```
  $ time lua fibt.lua
  real  0m0.099s
  user  0m0.096s
  sys   0m0.002s

  $ time glua fibt.lua
  real  0m0.489s
  user  0m0.484s
  sys   0m0.005s

  $ time go-lua fibt.lua
  real  0m0.607s
  user  0m0.610s
  sys   0m0.068s
```

Finally, we can write an explicitly iterative implementation:
```lua
  function fib(n)
    if n == 0 then
      return 0
    else if n == 1 then
      return 1
    end
    local n0, n1 = 0, 1
    for i = n, 2, -1 do
      local tmp = n0 + n1
      n0 = n1
      n1 = tmp
    end
    return n1
  end
```

This exercises more of the bytecode interpreter’s inner loop. Here we see the performance impact of Go’s `switch` implementation. Both go-lua and gopher-lua are an order of magnitude slower than the C Lua interpreter.
```
  $ time lua fibi.lua
  real  0m0.023s
  user  0m0.020s
  sys   0m0.003s

  $ time glua fibi.lua
  real  0m0.242s
  user  0m0.235s
  sys   0m0.005s

  $ time go-lua fibi.lua
  real  0m0.242s
  user  0m0.240s
  sys   0m0.028s
```

License
-------

go-lua is licensed under the [MIT license](https://github.com/Shopify/go-lua/blob/master/LICENSE.md).


go-lua

# go-lua

A Lua 5.4 VM in pure Go — no CGo, no dependencies.

This is a fork of [Shopify/go-lua](https://github.com/Shopify/go-lua), upgraded from Lua 5.3 to **Lua 5.4**.

## What's new compared to Shopify/go-lua?

- Native 64-bit integers (`int64`) alongside floats (`float64`)
- Bitwise operators: `&`, `|`, `~`, `<<`, `>>` and unary `~`
- Integer division: `//`
- Coroutines: `coroutine.create`, `resume`, `yield`, `wrap`, `status`, `running`, `close`, `isyieldable`
- UTF-8 library: `utf8.char`, `utf8.codes`, `utf8.codepoint`, `utf8.len`, `utf8.offset`
- String packing: `string.pack`, `string.unpack`, `string.packsize`
- String dump: `string.dump` (with strip option)
- Math extensions: `math.tointeger`, `math.type`, `math.ult`, `math.maxinteger`, `math.mininteger`
- Table move: `table.move(a1, f, e, t [,a2])`
- Table metamethods: `table.insert`, `table.remove`, `table.sort` respect `__index`/`__newindex`
- Hex float format: `string.format` supports `%a`/`%A`
- To-be-closed variables: `<close>` attribute and `__close` metamethod
- Const variables: `<const>` attribute
- Generalized `for` with to-be-closed control variable
- `warn()` function
- Debug library: `debug.getlocal`, `debug.setlocal`, `debug.getinfo`, `debug.sethook` (including coroutine hooks)

## Getting started

```sh
go get github.com/speedata/go-lua
```

A minimal example:

```go
package main

import "github.com/speedata/go-lua"

func main() {
    l := lua.NewState()
    lua.OpenLibraries(l)
    if err := lua.DoFile(l, "hello.lua"); err != nil {
        panic(err)
    }
}
```

### Calling Lua from Go

```go
l := lua.NewState()
lua.OpenLibraries(l)

lua.DoString(l, `
    function greet(name)
        return "Hello, " .. name .. "!"
    end
`)

l.Global("greet")
l.PushString("World")
l.Call(1, 1)
result, _ := l.ToString(-1)
fmt.Println(result) // Hello, World!
```

### Registering Go functions in Lua

```go
l := lua.NewState()
lua.OpenLibraries(l)

l.Register("add", func(l *lua.State) int {
    a := lua.CheckNumber(l, 1)
    b := lua.CheckNumber(l, 2)
    l.PushNumber(a + b)
    return 1
})

lua.DoString(l, `print(add(2, 3))`) // 5
```

## Test suite status

We run the official Lua 5.4 test suites. Currently **21 out of 25** pass:

| Test | Status | Notes |
|------|--------|-------|
| bitwise | Pass | |
| calls | Pass | |
| closure | Pass | |
| code | Pass | |
| constructs | Pass | |
| coroutine | Pass | |
| db (debug) | Pass | |
| errors | Pass | |
| events | Pass | |
| files | Pass | |
| goto | Pass | |
| literals | Pass | |
| locals | Pass | |
| math | Pass | |
| nextvar | Pass | |
| pm (pattern matching) | Pass | |
| sort | Pass | |
| strings | Pass | |
| tpack (string.pack) | Pass | |
| utf8 | Pass | |
| vararg | Pass | |
| attrib | — | Needs weak references |
| gc | — | Go's GC, not controllable like Lua's |
| big | — | Tables with >2^18 elements |
| main | — | Requires standalone Lua binary |

## Known limitations

- **No weak references** — `__mode` on metatables is not supported (Go's GC doesn't offer that hook)
- **No C API** — pure Go, so C Lua libraries won't work (that's kind of the point though)

## Development

```sh
git clone https://github.com/speedata/go-lua.git
go build ./...
go test ./...
```

Some tests optionally use `luac` 5.4 for compiling Lua source to bytecode. If it's not in your PATH, those tests get skipped automatically.

## License

MIT — see [LICENSE.md](LICENSE.md).

Originally forked from [Shopify/go-lua](https://github.com/Shopify/go-lua).


gopher-lua

A highly customizable expression language written in Go

# Gval

[![Go Reference](https://pkg.go.dev/badge/github.com/PaesslerAG/gval.svg)](https://pkg.go.dev/github.com/PaesslerAG/gval)
[![Build Status](https://api.travis-ci.org/PaesslerAG/gval.svg?branch=master)](https://travis-ci.org/PaesslerAG/gval)
[![Coverage Status](https://coveralls.io/repos/github/PaesslerAG/gval/badge.svg?branch=master)](https://coveralls.io/github/PaesslerAG/gval?branch=master)
[![Go Report Card](https://goreportcard.com/badge/github.com/PaesslerAG/gval)](https://goreportcard.com/report/github.com/PaesslerAG/gval)

Gval (Go eVALuate) provides support for evaluating arbitrary expressions, in particular Go-like expressions.

![gopher](./prtg-batmin-gopher.png)

## Evaluate

Gval can evaluate expressions with parameters, arimethetic, logical, and string operations:

- basic expression: [10 > 0](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-Basic)
- parameterized expression: [foo > 0](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-Parameter)
- nested parameterized expression: [foo.bar > 0](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-NestedParameter)
- arithmetic expression: [(requests_made * requests_succeeded / 100) >= 90](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-Arithmetic)
- string expression: [http_response_body == "service is ok"](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-String)
- float64 expression: [(mem_used / total_mem) * 100](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-Float64)

It can easily be extended with custom functions or operators:

- custom date comparator: [date(\`2014-01-02\`) > date(\`2014-01-01 23:59:59\`)](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-DateComparison)
- string length: [strlen("someReallyLongInputString") <= 16](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-Strlen)

You can parse gval.Expressions once and re-use them multiple times. Parsing is the compute-intensive phase of the process, so if you intend to use the same expression with different parameters, just parse it once:

- [Parsing and Evaluation](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluable)

The normal Go-standard order of operators is respected. When writing an expression, be sure that you either order the operators correctly, or use parentheses to clarify which portions of an expression should be run first.

Strings, numbers, and booleans can be used like in Go:

- [(7 < "47" == true ? "hello world!\n\u263a") + \` more text\`](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-Encoding)

## Parameter

Variables can be accessed via string literals. They can be used for values with string keys if the parameter is a `map[string]interface{}` or `map[interface{}]interface{}` and for fields or methods if the parameter is a struct.

- [foo > 0](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-Parameter)

### Bracket Selector

Map and array elements and Struct Field can be accessed via `[]`.

- [foo[0]](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-Array)
- [foo["b" + "a" + "r"]](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-ExampleEvaluate_ComplexAccessor)

### Dot Selector

A nested variable with a name containing only letters and underscores can be accessed via a dot selector.

- [foo.bar > 0](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-NestedParameter)

### Custom Selector

Parameter names like `response-time` will be interpreted as `response` minus `time`. While gval doesn't support these parameter names directly, you can easily access them via a custom extension like [JSON Path](https://github.com/PaesslerAG/jsonpath):

- [$["response-time"]](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-Jsonpath)

Jsonpath is also suitable for accessing array elements.

### Fields and Methods

If you have structs in your parameters, you can access their fields and methods in the usual way:

- [foo.Hello + foo.World()](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-FlatAccessor)

It also works if the parameter is a struct directly
[Hello + World()](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-Accessor)
or if the fields are nested
[foo.Hello + foo.World()](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Evaluate-NestedAccessor)

This may be convenient but note that using accessors on strucs makes the expression about four times slower than just using a parameter (consult the benchmarks for more precise measurements on your system). If there are functions you want to use, it's faster (and probably cleaner) to define them as functions (see the Evaluate section). These approaches use no reflection, and are designed to be fast and clean.

## Default Language

The default language is in serveral sub languages like text, arithmetic or propositional logic defined. See [Godoc](https://pkg.go.dev/github.com/PaesslerAG/gval/#Gval) for details. All sub languages are merged into gval.Full which contains the following elements:

- Modifiers: `+` `-` `/` `*` `&` `|` `^` `**` `%` `>>` `<<`
- Comparators: `>` `>=` `<` `<=` `==` `!=` `=~` `!~`
- Logical ops: `||` `&&`
- Numeric constants, as 64-bit floating point (`12345.678`)
- String constants (double quotes: `"foobar"`)
- Date function 'Date(x)', using any permutation of RFC3339, ISO8601, ruby date, or unix date
- Boolean constants: `true` `false`
- Parentheses to control order of evaluation `(` `)`
- Json Arrays : `[1, 2, "foo"]`
- Json Objects : `{"a":1, "b":2, "c":"foo"}`
- Prefixes: `!` `-` `~`
- Ternary conditional: `?` `:`
- Null coalescence: `??`

## Customize

Gval is completly customizable. Every constant, function or operator can be defined separately and existing expression languages can be reused:

- [foo.Hello + foo.World()](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-Language)

For details see [Godoc](https://pkg.go.dev/github.com/PaesslerAG/gval).

### Implementing custom selector

In a case you want to provide custom logic for selectors you can implement `SelectGVal(ctx context.Context, k string) (interface{}, error)` on your struct.
Function receives next part of the path and can return any type of var that is again evaluated through standard gval procedures.

[Example Custom Selector](https://pkg.go.dev/github.com/PaesslerAG/gval/#example-custom-selector)

### External gval Languages

A list of external libraries for gval. Feel free to add your own library.

- [gvalstrings](https://github.com/generikvault/gvalstrings) parse single quoted strings in gval.
- [jsonpath](https://github.com/PaesslerAG/jsonpath) full support for jsonpath in gval.

## Performance

The library is built with the intention of being quick but has not been aggressively profiled and optimized. For most applications, though, it is completely fine.
If performance is an issue, make sure to create your expression language with all functions, constants and operators only once. Evaluating an expression like gval.Evaluate("expression, const1, func1, func2, ...) creates a new gval.Language everytime it is called and slows execution.

The library comes with a bunch of benchmarks to measure the performance of parsing and evaluating expressions. You can run them with `go test -bench=.`.

For a very rough idea of performance, here are the results from a benchmark run on a Dell Latitude E7470 Win 10 i5-6300U.

``` text
BenchmarkGval/const_evaluation-4                               500000000                 3.57 ns/op
BenchmarkGval/const_parsing-4                                    1000000              1144 ns/op
BenchmarkGval/single_parameter_evaluation-4                     10000000               165 ns/op
BenchmarkGval/single_parameter_parsing-4                         1000000              1648 ns/op
BenchmarkGval/parameter_evaluation-4                             5000000               352 ns/op
BenchmarkGval/parameter_parsing-4                                 500000              2773 ns/op
BenchmarkGval/common_evaluation-4                                3000000               434 ns/op
BenchmarkGval/common_parsing-4                                    300000              4419 ns/op
BenchmarkGval/complex_evaluation-4                             100000000                11.6 ns/op
BenchmarkGval/complex_parsing-4                                   100000             17936 ns/op
BenchmarkGval/literal_evaluation-4                             300000000                 3.84 ns/op
BenchmarkGval/literal_parsing-4                                   500000              2559 ns/op
BenchmarkGval/modifier_evaluation-4                            500000000                 3.54 ns/op
BenchmarkGval/modifier_parsing-4                                  500000              3755 ns/op
BenchmarkGval/regex_evaluation-4                                   50000             21347 ns/op
BenchmarkGval/regex_parsing-4                                     200000              6480 ns/op
BenchmarkGval/constant_regex_evaluation-4                        1000000              1000 ns/op
BenchmarkGval/constant_regex_parsing-4                            200000              9417 ns/op
BenchmarkGval/accessors_evaluation-4                             3000000               417 ns/op
BenchmarkGval/accessors_parsing-4                                1000000              1778 ns/op
BenchmarkGval/accessors_method_evaluation-4                      1000000              1931 ns/op
BenchmarkGval/accessors_method_parsing-4                         1000000              1729 ns/op
BenchmarkGval/accessors_method_parameter_evaluation-4            1000000              2162 ns/op
BenchmarkGval/accessors_method_parameter_parsing-4                500000              2618 ns/op
BenchmarkGval/nested_accessors_evaluation-4                      2000000               681 ns/op
BenchmarkGval/nested_accessors_parsing-4                         1000000              2115 ns/op
BenchmarkRandom-4                                                 500000              3631 ns/op
ok
```

## API Breaks

Gval is designed with easy expandability in mind and API breaks will be avoided if possible. If API breaks are unavoidable they wil be explicitly stated via an increased major version number.

-------------------------------------
Credits to Reene French for the gophers.


The Best Go Libraries For Embeddable Scripting Languages (25)

golua

anko

binder

cel-go

ecal

expr

gentee

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goal

goja

ngaro

prolog

purl

starlark-go

starlet

tengo

Wa/凹语言

metacall

FrankenPHP

gisp

go-lua

go-lua

gopher-lua

gval