@rmw/coffee-label-patch

Make coffeescript support :label syntax (similar to livescript) so that it can be used for svelte.

It's too hard to modify the compiler based on lex, ast, and I did this based on string substitution.

This is just a crude hack, but it does work.

Expect coffee to officially add this syntax.

Install

yarn add @rmw/coffee-label-patch or npm install @rmw/coffee-label-patch

Use

#!/usr/bin/env coffee

import CoffeeScript from "coffeescript"
import hack from '@rmw/coffee-label-patch'
hack CoffeeScript
console.log CoffeeScript.compile(
  """
y = 0

:$ x=y*2

:$ if y>2 then x+=y else x-=y

:$
  if x > y
    x = y/2
  else
    x = y+9
  x += 1

do =>
  + a,b

:$ func = => 1

:$ func = ->
  1
  2

do =>
  :out
    for i in [1,2,3]
      for j in [4,5,6]
        console.log i,j
        if i > 1
          break out
  return

< x
< x = 1

  """
  bare:true
  #  sourceMap:true
)

output :

var x, y;

y = 0;

$ : x = y * 2;

$ : y > 2 ? x += y : x -= y;

$ : {
  if (x > y) {
    x = y / 2;
  } else {
    x = y + 9;
  }
  x += 1;
}

(() => {
  var i, j, k, l, len, len1, ref, ref1;
  out : {
    ref = [1, 2, 3];
    for (k = 0, len = ref.length; k < len; k++) {
      i = ref[k];
      ref1 = [4, 5, 6];
      for (l = 0, len1 = ref1.length; l < len1; l++) {
        j = ref1[l];
        console.log(i, j);
        if (i > 1) {
          break out;
        }
      }
    }
  }
})();

then node test.out.js , stdout is

1 4
1 5
1 6
2 4

中文说明

让 coffeescript 支持 :label 语法（类似 livescript），这样就可以用于 svelte 。

基于 lex 、 ast 去修改编译器太难了，我基于字符串替换做到这个功能。

这只是一个粗糙的hack。但它的确能工作。

期待coffee正式加入此语法。

关于

本项目隶属于人民网络(rmw.link) 代码计划。