MoonScript - Programming language

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MoonScript is an open source programming language created in 2011.

#185on PLDB

13Years Old

818Repos

Download source code:

git clone https://github.com/leafo/moonscript

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:crescent_moon: A language that compiles to Lua

Tags: programming language
MoonScript is developed on GitHub and has 3,166 stars
There are at least 818 MoonScript repos on GitHub
Early development of MoonScript happened in https://github.com/leafo/moonscript/issues
MoonScript compiles to Lua
MoonScript is written in Lua, Markdown, YAML, Make, Bourne shell, C
The Google BigQuery Public Dataset GitHub snapshot shows 276 users using MoonScript in 359 repos on GitHub
Explore MoonScript snippets on Rosetta Code
Pygments supports syntax highlighting for MoonScript
GitHub supports syntax highlighting for MoonScript

Example from the web:

class Thing
  name: "unknown"

class Person extends Thing
  say_name: => print "Hello, I am #{@name}!"

with Person!
  .name = "MoonScript"
  \say_name!

Example from hello-world:

print 'Hello World'

Example from Linguist:


types = require "moonscript.types"
util = require "moonscript.util"
data = require "moonscript.data"

import reversed, unpack from util
import ntype, mtype, build, smart_node, is_slice, value_is_singular from types
import insert from table
import NameProxy, LocalName from require "moonscript.transform.names"

destructure = require "moonscript.transform.destructure"

local implicitly_return

class Run
  new: (@fn) =>
    self[1] = "run"

  call: (state) =>
    self.fn state

-- transform the last stm is a list of stms
-- will puke on group
apply_to_last = (stms, fn) ->
  -- find last (real) exp
  last_exp_id = 0
  for i = #stms, 1, -1
    stm = stms[i]
    if stm and mtype(stm) != Run
      last_exp_id = i
      break

  return for i, stm in ipairs stms
    if i == last_exp_id
      fn stm
    else
      stm

-- is a body a sindle expression/statement
is_singular = (body) ->
  return false if #body != 1
  if "group" == ntype body
    is_singular body[2]
  else
    true

find_assigns = (body, out={}) ->
  for thing in *body
    switch thing[1]
      when "group"
        find_assigns thing[2], out
      when "assign"
        table.insert out, thing[2] -- extract names
  out

hoist_declarations = (body) ->
  assigns = {}

  -- hoist the plain old assigns
  for names in *find_assigns body
    for name in *names
      table.insert assigns, name if type(name) == "string"

  -- insert after runs
  idx = 1
  while mtype(body[idx]) == Run do idx += 1

  table.insert body, idx, {"declare", assigns}

expand_elseif_assign = (ifstm) ->
  for i = 4, #ifstm
    case = ifstm[i]
    if ntype(case) == "elseif" and ntype(case[2]) == "assign"
      split = { unpack ifstm, 1, i - 1 }
      insert split, {
        "else", {
          {"if", case[2], case[3], unpack ifstm, i + 1}
        }
      }
      return split

  ifstm

constructor_name = "new"

with_continue_listener = (body) ->
  continue_name = nil
  {
    Run =>
      @listen "continue", ->
        unless continue_name

Language features

Feature	Supported	Example	Token
Booleans	✓		true false
Strings	✓	'Hello world'	'
Print() Debugging	✓		print
Comments	✓	-- A comment
Line Comments	✓	-- A comment	--
Semantic Indentation	X