Reinterpreter/compiler for my Lua class library

classcompiler.lua

local classcompiler = {}

--[[
-- Example syntax:
class MyClass {
    num = 0

    function __init(num)
        self.num = num
    end
    
    static function ClassName()
        return MyClass._class
    end

    function MyFunc()
        return self.num
    end
}

class MyChild extends MyClass {
    function MyFunc()
        return self.num * 2
    end
}
]]

local class_min_lua = [[-- class.min.lua
local class; do
    local metamethods = {__add=true, __sub=true, __mul=true, __div=true, __mod=true, __pow=true, __unm=true, __concat=true, __len=true, __eq=true, __lt=true, __le=true, __newindex=true, __call=true, __metatable=true}
    local function tabset(t, k, v) t[k] = v; return t end
    local function _wrap_method(obj, func, ...) return setfenv(func, tabset(tabset(getfenv(func), "self", obj), "super", setmetatable({}, {__index = getmetatable(obj).__index})))(...) end
    local function defineClass(name, meta, def)
        local c, cmt = {__class = name}, {}
        if def.static then for k,v in pairs(def.static) do if metamethods[k] then cmt[k] = v else c[k] = v end end end
        def.static = nil
        if meta.extends then if meta.extends[1] then cmt.__index = function(self, name) for i,v in ipairs(meta.extends) do if v[name] then return v[name] end end end else cmt.__index = meta.extends end end
        local __init = def.__init
        def.__init = nil
        cmt.__call = function(self, ...)
            local omt, supers = {}, {}
            local obj = setmetatable({__class = name}, omt)
            if meta.extends and not __init then if meta.extends[1] then for i,v in ipairs(meta.extends) do supers[i] = v() end omt.__index = function(self, name) for i,v in ipairs(supers) do if v[name] then return v[name] end end end else omt.__index = meta.extends(...) end end
            for k,v in pairs(def) do if type(v) == "function" then obj[k] = function(...) _wrap_method(obj, v, ...) end elseif k ~= "__class" then obj[k] = v end if metamethods[k] then omt[k] = obj[k]; obj[k] = nil end end
            if __init then 
                local env = tabset(tabset(getfenv(__init), "self", obj), "super", setmetatable({}, {__index = omt.__index}))
                if meta.extends then if meta.extends[1] then omt.__index = function(self, name) if #supers < #meta.extends then for i,v in ipairs(meta.extends) do supers[i] = v() end end for i,v in ipairs(supers) do if v[name] then return v[name] end end end for i,v in ipairs(meta.extends) do env[v.__class] = function(...) supers[i] = v(...) end end else omt.__index = function(self, name) omt.__index = meta.extends(); return omt.__index[name] end env[meta.extends.__class] = function(...) omt.__index = meta.extends(...) end end end
                setfenv(__init, env)(...)
                if meta.extends and meta.extends[1] then omt.__index = function(self, name) for i,v in ipairs(supers) do if v[name] then return v[name] end end end end
            end
            return obj
        end
        --return tabset(_G, name, setmetatable(c, cmt))[name]
        return setmetatable(c, cmt)
    end
    class = setmetatable({}, {__call = function(self, name) return function(tab) if tab.extends or tab.implements then return function(impl) return defineClass(name, tab, impl) end else return defineClass(name, {}, tab) end end end})
end
-- end class.min.lua

]]

local keywords = {["do"] = 1, ["then"] = 1, ["repeat"] = 1, ["function"] = 1, ["function"] = 1, ["end"] = -1}

local function replacement(extends, nl)
    return function(name, contents, extra)
        local str = "local " .. name .. " = class \"" .. name .. "\" "
        local static = ""
        local isStatic = false
        local function append(s) if isStatic then static = static .. s else str = str .. s end end
        local function getstr() return isStatic and static or str end
        if nl then str = "\n" .. str end
        if extends then 
            local ext = contents:gsub(" +$", "")
            contents = extra
            if ext:find(",") then str = str .. "{extends = {" .. ext .. "}} "
            else str = str .. "{extends = " .. ext .. "} " end
        end
        local current, stop = contents:find("[^\n]+")
        local level = 0
        local quote = 0
        while current do
            local ss = contents:sub(current, stop)
            --print(ss)
            if level == 0 then
                local ss_short = ss:gsub("^[ \t]+", ""):gsub(" +$", "")
                if ss_short == "{" or ss_short == "}" or ss_short == "" then
                    append(ss .. "\n")
                elseif ss_short:find("function") then
                    --print("Match ", ss:match("^( +)function +([a-zA-Z_][a-zA-Z0-9_]*)%("))
                    local offset = 0
                    if ss_short:find("static +function") then isStatic = true; offset = #ss:match("(static +)function"); ss = ss:gsub("static +function", "function") end
                    local newss = ss:gsub("^([ \t]+)function +([a-zA-Z_][a-zA-Z0-9_]*)%(", "%1%2 = function("):gsub("^([ \t]+)static +function +([a-zA-Z_][a-zA-Z0-9_]*)%(", "%1%2 = function("):gsub("(function%b()).+", "%1")
                    level = 1
                    stop = current + #ss:match("^.+function[^(]*%b()") + offset
                    append(newss .. (ss == ss:match("^.+function[^(]*%b()") and "\n" or " "))
                else
                    append(ss .. ",\n")
                end
            else
                local key = ""
                for c in ss:gmatch(".") do
                    if quote == 0 then
                        if c == '"' then quote = 1
                        elseif c == "'" then quote = 2 end
                        if keywords[key] and (c == ' ' or c == '(' or c == '"' or c == "'" or c == '\n') then level = level + keywords[key]; key = ""
                        elseif #key == 0 and (c == 'e' or c == 'd' or c == 't' or c == 'r' or c == 'f') then key = c
                        elseif key == 'e' and c == 'n' then key = "en"
                        elseif key == 'd' and c == 'o' then key = "do"
                        elseif key == 't' and c == 'h' then key = "th"
                        elseif key == 'f' and c == 'u' then key = "fu"
                        elseif key == "en" and c == 'd' then key = "end"
                        elseif key == "th" and c == 'e' then key = "the"
                        elseif key == "fu" and c == 'n' then key = "fun"
                        elseif key == "the" and c == 'n' then key = "then"
                        elseif key == "fun" and c == 'c' then key = "func"
                        elseif key == "func" and c == 't' then key = "funct"
                        elseif key == "funct" and c == 'i' then key = "functi"
                        elseif key == "functi" and c == 'o' then key = "functio"
                        elseif key == "functio" and c == 'n' then key = "function"
                        else key = "" end
                    elseif quote == 1 and c == '"' then quote = 0; key = ""
                    elseif quote == 2 and c == "'" then quote = 0; key = "" end
                end
                if keywords[key] then level = level + keywords[key] end
                if getstr():sub(-1) == "\n" then append((" "):rep(4*level+4)) end
                append(ss .. (level == 0 and ",\n" or (contents:sub(stop+1, stop+1) == "\n" and "\n" or " ")))
                if level == 0 then isStatic = false end
            end
            if level == 0 then current, stop = contents:find("[^\n]+", stop + 1) else current, stop = contents:find("[^ \n\t]+", stop + 1) end
        end
        if static ~= "" then return str:gsub("(local " .. name .. " = class \"" .. name .. "\" {)([^e])", "%1\nstatic = {\n" .. static .. "},\n%2"):gsub("(local " .. name .. " = class \"" .. name .. "\" %b{} {)([^e])", "%1\nstatic = {\n" .. static .. "},\n%2")
        else return str end
    end
end

function classcompiler.compile(s)
    local retval = class_min_lua
    retval = retval .. s:gsub("\n[ \t]*class +([A-Za-z_][A-Za-z0-9_]*) *(%b{})", replacement(false, true))
                        :gsub("\n[ \t]*class +([A-Za-z_][A-Za-z0-9_]*) +extends +([a-zA-Z0-9_, ]+) *(%b{})", replacement(true, true))
                        :gsub("^[ \t]*class +([A-Za-z_][A-Za-z0-9_]*) *(%b{})", replacement(false, false))
                        :gsub("^[ \t]*class +([A-Za-z_][A-Za-z0-9_]*) +extends +([a-zA-Z0-9_, ]+) *(%b{})", replacement(true, false))
    return retval
end

function classcompiler.loadstring(str, name) -- Lua 5.1
    return loadstring(classcompiler.compile(str), name)
end

if pcall(require, "classcompiler") and shell then -- ComputerCraft console
    local args = {...}
    if #args < 1 then printError("Usage: classcompiler <file.lua> [args...]\n       classcompiler -c <in.lua> <out.lua>"); return false end
    if args[1] == "-c" then
        if #args < 3 then printError("Usage: classcompiler <file.lua> [args...]\n       classcompiler -c <in.lua> <out.lua>"); return false end
        local file = fs.open(shell.resolve(args[2]), "r")
        if file == nil then error("Could not open input file " .. args[2]) end
        local out = fs.open(shell.resolve(args[3]), "w")
        out.write(classcompiler.compile(file.readAll()))
        file.close()
        out.close()
        return true
    else
        local name = shell.resolve(table.remove(args, 1))
        local file = fs.open(name, "r")
        if file == nil then error("Could not open input file " .. args[2]) end
        local contents = file.readAll()
        file.close()
        local fn, err = classcompiler.loadstring(contents, "@" .. name)
        if fn == nil then printError(err); return false end
        setfenv(fn, _ENV)
        return fn(table.unpack(args))
    end
end

return classcompiler

test-output.lua

-- class.min.lua
local class; do
    local metamethods = {__add=true, __sub=true, __mul=true, __div=true, __mod=true, __pow=true, __unm=true, __concat=true, __len=true, __eq=true, __lt=true, __le=true, __newindex=true, __call=true, __metatable=true}
    local function tabset(t, k, v) t[k] = v; return t end
    local function _wrap_method(obj, func, ...) return setfenv(func, tabset(tabset(getfenv(func), "self", obj), "super", setmetatable({}, {__index = getmetatable(obj).__index})))(...) end
    local function defineClass(name, meta, def)
        local c, cmt = {__class = name}, {}
        if def.static then for k,v in pairs(def.static) do if metamethods[k] then cmt[k] = v else c[k] = v end end end
        def.static = nil
        if meta.extends then if meta.extends[1] then cmt.__index = function(self, name) for i,v in ipairs(meta.extends) do if v[name] then return v[name] end end end else cmt.__index = meta.extends end end
        local __init = def.__init
        def.__init = nil
        cmt.__call = function(self, ...)
            local omt, supers = {}, {}
            local obj = setmetatable({__class = name}, omt)
            if meta.extends and not __init then if meta.extends[1] then for i,v in ipairs(meta.extends) do supers[i] = v() end omt.__index = function(self, name) for i,v in ipairs(supers) do if v[name] then return v[name] end end end else omt.__index = meta.extends(...) end end
            for k,v in pairs(def) do if type(v) == "function" then obj[k] = function(...) _wrap_method(obj, v, ...) end elseif k ~= "__class" then obj[k] = v end if metamethods[k] then omt[k] = obj[k]; obj[k] = nil end end
            if __init then 
                local env = tabset(tabset(getfenv(__init), "self", obj), "super", setmetatable({}, {__index = omt.__index}))
                if meta.extends then if meta.extends[1] then omt.__index = function(self, name) if #supers < #meta.extends then for i,v in ipairs(meta.extends) do supers[i] = v() end end for i,v in ipairs(supers) do if v[name] then return v[name] end end end for i,v in ipairs(meta.extends) do env[v.__class] = function(...) supers[i] = v(...) end end else omt.__index = function(self, name) omt.__index = meta.extends(); return omt.__index[name] end env[meta.extends.__class] = function(...) omt.__index = meta.extends(...) end end end
                setfenv(__init, env)(...)
                if meta.extends and meta.extends[1] then omt.__index = function(self, name) for i,v in ipairs(supers) do if v[name] then return v[name] end end end end
            end
            return obj
        end
        --return tabset(_G, name, setmetatable(c, cmt))[name]
        return setmetatable(c, cmt)
    end
    class = setmetatable({}, {__call = function(self, name) return function(tab) if tab.extends or tab.implements then return function(impl) return defineClass(name, tab, impl) end else return defineClass(name, {}, tab) end end end})
end
-- end class.min.lua

local foo = class "foo" {
static = {
    whoIs = function(obj)
        return obj.name
    end,
},

    name = "person",
    hello = function()
        print("Hello, " .. self.name .. "!")
    end,
    __init = function(name)
        self.name = name
    end,
}


local bar = class "bar" {extends = foo} {
    hello = function()
        super.hello()
        print("How are you?")
    end,
}


local obj = foo("world")
print("Foo's name is " .. foo.whoIs(obj))
obj.hello()

local baz = bar("my friend")
baz.hello()

--------

local a = class "a" {
    fn = function()
        print("A")
    end,
}


local b = class "b" {extends = a} {
    fn = function()
        print("B")
    end,
}


local c = class "c" {extends = a} {
    fn = function()
        print("C")
    end,
}


local d = class "d" {extends = {b, c}} {
}


local test = d()
test.fn()

--------

local shape = class "shape" {
    __init = function(sides)
        if type(sides) ~= "number" then error("bad argument #1 (expected number, got " .. type(sides) .. ")") end
        self.sides = sides
    end,
}


local rectangle = class "rectangle" {extends = shape} {
    __init = function(width, height)
        _ENV.shape(4)
        if type(width) ~= "number" then error("bad argument #1 (expected number, got " .. type(width) .. ")") end
        if type(height) ~= "number" then error("bad argument #2 (expected number, got " .. type(height) .. ")") end
        self.width = width
        self.height = height
    end,
}


local equiangular = class "equiangular" {extends = shape} {
    __init = function(sides)
        _ENV.shape(sides)
        self.angle = (180 * (sides - 2)) / sides
    end,
}


local square = class "square" {extends = {rectangle, equiangular}} {
    __init = function(width)
        _ENV.rectangle(width, width)
        _ENV.equiangular(4)
    end,
}


local s = square(10)
print("Width: " .. s.width .. ", height: " .. s.height .. ", angle: " .. s.angle .. ", sides: " .. s.sides)

--------

local person = class "person" {
    __init = function(name)
        self.name = name
    end,
    say = function(text)
        print(self.name .. " says, \"" .. text .. "\"")
    end,
}


local alice = person("Alice")
local bob = person("Bob")
alice.say("Hi, Bob!")
bob.say("Hi, how are you?")
alice.say("Very well, and you?")
bob.say("Good!")

test.lua

class foo {
    static function whoIs(obj)
        return obj.name
    end
    name = "person"
    function hello()
        print("Hello, " .. self.name .. "!")
    end
    function __init(name)
        self.name = name
    end
}

class bar extends foo {
    function hello()
        super.hello()
        print("How are you?")
    end
}

local obj = foo("world")
print("Foo's name is " .. foo.whoIs(obj))
obj.hello()

local baz = bar("my friend")
baz.hello()

--------

class a {
    function fn()
        print("A")
    end
}

class b extends a {
    function fn()
        print("B")
    end
}

class c extends a {
    function fn()
        print("C")
    end
}

class d extends b, c {

}

local test = d()
test.fn()

--------

class shape {
    function __init(sides)
        if type(sides) ~= "number" then error("bad argument #1 (expected number, got " .. type(sides) .. ")") end
        self.sides = sides
    end
}

class rectangle extends shape {
    function __init(width, height)
        _ENV.shape(4)
        if type(width) ~= "number" then error("bad argument #1 (expected number, got " .. type(width) .. ")") end
        if type(height) ~= "number" then error("bad argument #2 (expected number, got " .. type(height) .. ")") end
        self.width = width
        self.height = height
    end
}

class equiangular extends shape {
    function __init(sides)
        _ENV.shape(sides)
        self.angle = (180 * (sides - 2)) / sides
    end
}

class square extends rectangle, equiangular {
    function __init(width)
        _ENV.rectangle(width, width)
        _ENV.equiangular(4)
    end
}

local s = square(10)
print("Width: " .. s.width .. ", height: " .. s.height .. ", angle: " .. s.angle .. ", sides: " .. s.sides)

--------

class person {
    function __init(name)
        self.name = name
    end
    function say(text)
        print(self.name .. " says, \"" .. text .. "\"")
    end
}

local alice = person("Alice")
local bob = person("Bob")
alice.say("Hi, Bob!")
bob.say("Hi, how are you?")
alice.say("Very well, and you?")
bob.say("Good!")