MoonScript REPL (using luarepl)

moonrepl.lua

#!/usr/bin/env lua

-- This is an example quick-implementation of a MoonScript REPL,
-- using LuaRepl.
--
-- Requires:
--  - moonscript and luarepl, of course
--  - log (https://github.com/romgrk/log.moon)
-- 
-- The additionnal 'log' is my personnal logging utility.
-- provided at https://github.com/romgrk/log.moon
-- It is NOT standard nor production-use oriented.
-- You could simply replace it by calls to print.
-- However it can pretty print, has support for term-coloring
-- and other utilities. (Bit & Hex dump)

local log        = require 'log'
local repl       = require 'repl.console'
local moonscript = require 'moonscript.base'

local options = {
    moon =  true,
    debug = false
}

local context = repl:getcontext()

--local metaenv = { }
--setmetatable(metaenv, {
    --__index = function (table, key)
        --log.info('access key: ' .. key, log.RST)
        --return context[key]
    --end,
    --__newindex = function (table, key, value)
        --log.debug('new key: ' .. key, log.RST, value)
        --rawset(context, key, value)
    --end
--})
context.log     = log
context.p       = log.pp
context.inspect = require 'inspect'
context.keys    = context._.keys

local function gather_results(success, ...)
    local n = select('#', ...)
    return success, { n = n, ... }
end

function repl:displayresults(results)
    for i, res in ipairs(results) do
        log.pp(res)
        context.it = res
    end
end

function repl:displayerror(err)
    log.err(err .. log.RST)
end

function repl:compilechunk(chunk)
    return loadstring(chunk, self:name())
end

function repl:handleline(line)
    local lua_code
    if options.moon then 
        local chunk  = "export *\n" .. self._buffer .. line
        lua_code, more = moonscript.to_lua(chunk)
        if not lua_code then
            self._buffer = ''
            self:displayerror(more)
            return 1
        end
    else
        lua_code = self._buffer .. line
    end

    --log.warn(lua_code .. log.RST)
    local f, err = self:compilechunk(lua_code)
    if f then
        self._buffer = ''
        setfenv(f, context)
        local success, results = gather_results(xpcall(f, function(...) return self:traceback(...) end))
        if success then
            self:displayresults(results)
        else
            self:displayerror(results[1])
        end
    else
        if self:detectcontinue(err) then
            self._buffer = chunk .. '\n'
            return 2
        else
            self:displayerror(err)
        end
    end
    return 1
end

-- Plugins
repl:loadplugin 'linenoise'
repl:loadplugin 'history'
repl:loadplugin 'completion'
repl:loadplugin 'filename_completion'
--repl:loadplugin 'autoreturn'

log.info('Moon REPL' .. log.RST)

repl:run()