go-ethereum/vendor/gopkg.in/olebedev/go-duktape.v3

Duktape bindings for Go(Golang)

Duktape is a thin, embeddable javascript engine. Most of the api is implemented. The exceptions are listed here.

Usage

The package is fully go-getable, no need to install any external C libraries.
So, just type go get gopkg.in/olebedev/go-duktape.v3 to install.

package main

import "fmt"
import "gopkg.in/olebedev/go-duktape.v3"

func main() {
  ctx := duktape.New()
  ctx.PevalString(`2 + 3`)
  result := ctx.GetNumber(-1)
  ctx.Pop()
  fmt.Println("result is:", result)
  // To prevent memory leaks, don't forget to clean up after
  // yourself when you're done using a context.
  ctx.DestroyHeap()
}

Go specific notes

Bindings between Go and Javascript contexts are not fully functional. However, binding a Go function to the Javascript context is available:

package main

import "fmt"
import "gopkg.in/olebedev/go-duktape.v3"

func main() {
  ctx := duktape.New()
  ctx.PushGlobalGoFunction("log", func(c *duktape.Context) int {
    fmt.Println(c.SafeToString(-1))
    return 0
  })
  ctx.PevalString(`log('Go lang Go!')`)
}

then run it.

$ go run *.go
Go lang Go!
$

Timers

There is a method to inject timers to the global scope:

package main

import "fmt"
import "gopkg.in/olebedev/go-duktape.v3"

func main() {
  ctx := duktape.New()

  // Let's inject `setTimeout`, `setInterval`, `clearTimeout`,
  // `clearInterval` into global scope.
  ctx.PushTimers()

  ch := make(chan string)
  ctx.PushGlobalGoFunction("second", func(_ *Context) int {
    ch <- "second step"
    return 0
  })
  ctx.PevalString(`
    setTimeout(second, 0);
    print('first step');
  `)
  fmt.Println(<-ch)
}

then run it

$ go run *.go
first step
second step
$

Also you can FlushTimers().

Command line tool

Install go get gopkg.in/olebedev/go-duktape.v3/....
Execute file.js: $GOPATH/bin/go-duk file.js.

Benchmarks

prog	time
otto	200.13s
anko	231.19s
agora	149.33s
GopherLua	8.39s
go-duktape	9.80s

More details are here.

Status

The package is not fully tested, so be careful.

Contribution

Pull requests are welcome! Also, if you want to discuss something send a pull request with proposal and changes. Convention: fork the repository and make changes on your fork in a feature branch.