• MoonCake
• Features
• Playground
• Highlight
  • class / struct / extension
  • guard / continue / switch / defer
  • import / closure / string expression
• Documentation
• Install
• Running
• Test
• Editor with LSP Support
  • App Market Installation
  • Local Installation
• Projects using MoonCake

MoonCake

MoonCake was a Swift like programming language that compiles into Lua, runs on Lua 5.1 and above, including LuaJIT.

Features

with differences from Lua

• always declare variable as local, unless using export keyword
• using { and } instead of keyword do, then, end to seperate code block
• support guard keyword, which must transfer control at scope end
• support switch keyword, you can case a lot of conditions at a time
• support continue keyword, implemented by goto, available in Lua 5.2 and LuaJIT
• support defer keyword in function scope, including anonymous function
• support class and struct for simpler Object Oriented programming
• support extension keyword for extend class/struct
• support import keyword for simpler require a lot of sub modules
• support convenient anonymous function form { in } likes in Swift
• support expression in string like print("5 + 3 = \(5 + 3)")

Playground

For it's a pure Lua transpiler, so it can directly running in any environment that Lua supports.

Try it out in your browser https://moocscript.fun.

Highlight

class / struct / extension

class Animal {

    foot = 2

    wing = 0

    fn init() {
    }

    fn canFly() {
        return self.wing > 0
    }
}

class Bird : Animal {

    fn init(wing) {
        self.foot = 2
        self.wing = wing or 2
    }
}

struct Songster {

    tune = 'do'

    fn canSing() {
        return true
    }
}

extension Bird: Songster {

    feather = true

    fn canRun() {
        return self.foot >= 4
    }
}

b = Bird()
print(b.foot) -- 2
print(b.wing) -- 2
print(b.tune) -- do
print(b.feather) -- true
print(b:canRun()) -- false
print(b:canFly()) -- true
print(b:canSing()) -- true

guard / continue / switch / defer

-- guard, continue, switch
do {
    for i, v in ipairs({'A', 'B', 'C', 'D', 'E'}) {
        guard i > 1 else {
            continue
        }
        switch v {
            case 'B', 'D':
                print('case \(v)')
            case 'C':
                break
            default:
                print('default \(v)')
        }
    }
}
-- print 'case B'
-- print 'case D'
-- print 'default E'

-- defer keyword
do {
    fn aboutDeferKeyword() {
        defer {
            print("defer block")
        }
        print("fn block")
        return "return value"
    }
    print(aboutDeferKeyword())
}
-- print 'fn block'
-- print 'defer block'
-- print 'return value'

import / closure / string expression

import Utils from "moocscript.utils" -- import Utils
import sort, concat from table {} -- import table.sort, table.concat

tbl = { "A", "B", "C" }

-- closure, or anonymous function
do {
    sort(tbl, { a, b in
        return a > b
    })
    print(concat(tbl))
}
-- print 'CBA'

-- string expression
print("Hello, world \(600 + 60 + 6) !")
-- Hello, world 666 !

Documentation

recommand install and running first, or get more straight expressions from examples/ dir, before dig into detials about the language.

• The Language
• CommandLine Usage
• Library Interface

Install

recommend install from LuaRocks

$ luarocks install mooncake

or edit Makefile for a custom install

$ vi Makefile
$ make install

or just run as playground in project root dir

$ export LUA_PATH=./?.lua
$ ./bin/moocscript

or just make to see other generation option

$ make
Usage:
	 make test 	# busted ./moocscript/?.lua
	 make out 	# busted ./out/moocscript/?.lua
	 make web 	# busted ./out/web/moocscript-web.lua
	 make gen 	# generate ./out/moocscript/?.lua from ./moocscript/?.mooc
	 make install 	# please edit Makefile first
	 make uninstall 	# please edit Makefile first

with requirement

• Lua >= 5.1 OR LuaJIT >= 2.0
• LuaFileSystem >= 1.5 (only if you need project building, bundling)

Running

check install first

$ moocscript -v
moocscript v0.8.20221204, Lua 5.4

then enter REPL without an editor

$ ./bin/moocscript -i
moocscript v0.7.20221006, Lua 5.4
> export * -- default global variable
> class Person {
	name = ''
	fn init(name) {
		self.name = name
	}
	fn intro() {
		return "My name is \(self.name)"
	}
}
> peter = Person("Peter")
> print(peter:intro())
My name is Peter

you can run .lua or .mooc source directly, support options below

$ moocscript
Usage: [OPTIONS] SOURCE.[lua|mooc]
        '' load SOURCE and run
        -h print help
        -a print AST
        -s print Lua code
        -i enter REPL
        -p generate Lua code with project config
        -v version

project config example is examples/proj/proj_config.mooc, you can see how to config it through CommandLine Usage.

Test

using busted, running from project dir, first make test before busted, for generating package.path including current moocscript/ dir.

$ luarocks install busted
$ make test
●●●●●●●●●●●●●●●●●●...
311 successes / 0 failures / 0 errors / 0 pending : 0.217144 seconds

you can install LuaCov to get code coverage report

$ luarocks install luacov
$ make test
$ busted -c
$ luacov
$ cat luacov.report.out | grep '^moocscript/'
...
moocscript/class.lua                                                    60   10     85.71%
moocscript/compile.lua                                                  906  39     95.87%
moocscript/core.lua                                                     65   19     77.38%
moocscript/parser.lua                                                   1156 23     98.05%
moocscript/utils.lua                                                    121  14     89.63%
...

Editor with LSP Support

MoocHelper is a High-performance MoonCake/Lua plugin, Language Server Protocol for MoonCake/Lua, modified from LuaHelper.

App Market Installation

• Click the Vs Code application market icon
• Search moochelper in the input box
• Click to install MoocHelper
• Marketplace url: https://marketplace.visualstudio.com/items?itemName=suchangnet.MoocHelper

Local Installation

• download a pre-build one in releases, or in gitee mirror.
• or create your own .vsix package with npm install -g vsce, then vsce package under luahelper-vscode dir

Projects using MoonCake

• mooncake.site
• lua-sql-orm
• cincau
• rpc_framework