#!/usr/bin/env nomsu -V4.12.12.8
#
    This file contains the implementation of an Object-Oriented programming system.
    
%globals.METAMETHOD_MAP = {..}
    "as text": "__tostring", "clean up": "__gc", "+ 1": "__add", "- 1": "__sub"
    "* 1": "__mul", "/ 1": "__div", "-": "__unm", "// 1": "__idiv", "mod 1": "__mod"
    "^ 1": "__pow", "& 1": "__band", "| 1": "__bor", "~ 1": "__bxor", "~": "__bnot"
    "<< 1": "__bshl", ">> 1": "__bshr", "== 1": "__eq", "< 1": "__lt", "<= 1": "__le"
    "set 1 = 2": "__newindex", size: "__len", iterate: "__ipairs"
    "iterate all": "__pairs"

test:
    object (Dog):
        (Dog).genus = "Canus"
        my action [set up]:
            %me.barks or= 0
        
        my action [bark, woof]:
            %barks = [: for % in 1 to %me.barks: add "Bark!"]
            return (%barks::joined with " ")
        
        my action [get pissed off]: %me.barks += 1
    %d = (Dog {barks: 2})
    assume (type of %d) == "Dog"
    assume (%d is a "Dog")
    assume %d.barks == 2
    assume ((%d::bark) == "Bark! Bark!")
    assume ((%d::woof) == "Bark! Bark!")
    %d::get pissed off
    assume (%d.barks == 3)
    assume ((%d::bark) == "Bark! Bark! Bark!")
    assume (%d.genus == "Canus")
    assume ("\(%d.class)" == "Dog")
    assume (%d.genus == "Canus")
    assume (%d.barks == 3)
    %d2 = (Dog {})
    assume (%d2.barks == 0) or barf "Default initializer failed"
    with {%d: Dog {barks: 1}}:
        assume ((%d::bark) == "Bark!")
    
    object (Corgi) extends (Dog):
        my action [sploot] "splooted"
        my action [bark, woof]:
            %barks = [: for % in 1 to %me.barks: add "Yip!"]
            return (%barks::joined with " ")
    
    %corg = (Corgi {})
    assume (%corg.barks == 0)
    with {%d: Corgi {barks: 1}}:
        assume ((%d::sploot) == "splooted") or barf "subclass method failed"
        assume ((%d::bark) == "Yip!") or barf "inheritance failed"
        assume ((%d::woof) == "Yip!")
    
    with {%d: Dog {barks: 2}}:
        assume ((%d::bark) == "Bark! Bark!")

(my action %actions %body) compiles to:
    lua> "\
        ..local fn_name = \%actions[1].stub:as_lua_id()
        local \%args = List(\%actions[1]:get_args())
        table.insert(\%args, 1, \(\%me))
        local lua = LuaCode("class.", fn_name, " = ", \(what (%args -> %body) compiles to))
        for i=2,#\%actions do
            local alias = \%actions[i]
            local alias_name = alias.stub:as_lua_id()
            local \%alias_args = List(alias:get_args())
            table.insert(\%alias_args, 1, \(\%me))
            lua:add("\\nclass.", alias_name, " = ")
            if \%args == \%alias_args then
                lua:add("class.", fn_name)
            else
                lua:add(\(what (%alias_args -> %actions.1) compiles to))
            end
        end
        return lua"

(object %classname extends %parent %class_body) compiles to:
    unless (%classname.type == "Action"):
        compile error at %classname "\
            ..Expected this to be an action, not a \%classname.type"
    
    for % in %classname:
        unless (% is text):
            compile error at % "Class names should not have arguments."
    
    return (..)
        Lua "\
            ..do
                local class = {name=\(quote %classname.stub)}
                class.__type = class.name
                setmetatable(class, {
                    __index=\(%parent as lua expr),
                    __tostring=function(cls) return cls.name end,
                    __call=function(cls, inst)
                        if inst == nil then return cls end
                        inst = setmetatable(inst, cls)
                        if inst.set_up then inst:set_up() end
                        return inst
                    end,
                })
                _ENV[class.name:as_lua_id()] = class
                class.__index = class
                class.class = class
                class.__tostring = function(inst)
                    return inst.name..getmetatable(Dict{}).__tostring(inst)
                end
                \(%class_body as lua)
                for stub,metamethod in pairs(globals.METAMETHOD_MAP) do
                    class[metamethod] = class[stub:as_lua_id()]
                end
            end"

(object %classname %class_body) parses as (..)
    object %classname extends (nil) %class_body