nomsu/core/metaprogramming.nom

#
    This File contains actions for making actions and compile-time actions and some helper
    functions to make that easier.

lua> ".."
    nomsu.COMPILE_ACTIONS["% -> %"] = function(nomsu, tree, \%args, \%body)
        local lua = LuaCode.Value(tree.source, "function(")
        if AST.is_syntax_tree(\%args, "Action") then \%args = \%args:get_args() end
        local lua_args = table.map(\%args, function(a) return AST.is_syntax_tree(a) and tostring(nomsu:compile(a)) or a end)
        lua:concat_append(lua_args, ", ")
        local body_lua = AST.is_syntax_tree(\%body) and nomsu:compile(\%body):as_statements("return ") or \%body
        body_lua:remove_free_vars(lua_args)
        body_lua:declare_locals()
        lua:append(")\n    ", body_lua, "\nend")
        return lua
    end

lua> ".."
    nomsu.COMPILE_ACTIONS["compile as %"] = function(nomsu, tree, \%action)
        local lua = LuaCode.Value(tree.source, "nomsu.COMPILE_ACTIONS[", repr(\%action.stub), "](")
        local lua_args = table.map(\%action:get_args(), function(a) return nomsu:compile(a) end)
        table.insert(lua_args, 1, "nomsu")
        table.insert(lua_args, 2, "tree")
        lua:concat_append(lua_args, ", ")
        lua:append(")")
        return lua
    end

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

lua> ".."
    nomsu.COMPILE_ACTIONS["compile % to %"] = function(nomsu, tree, \%actions, \%body)
        local \%args = {"nomsu", "tree", unpack(table.map(\%actions[1]:get_args(), function(a) return tostring(nomsu:compile(a)) end))}
        local lua = LuaCode(tree.source, "nomsu.COMPILE_ACTIONS[", repr(\%actions[1].stub),
            "] = ", \(compile as: %args -> %body))
        for i=2,#\%actions do
            local alias = \%actions[i]
            local \%alias_args = {"nomsu", "tree", unpack(table.map(alias:get_args(), function(a) return tostring(nomsu:compile(a)) end))}
            lua:append("\nnomsu.COMPILE_ACTIONS[", repr(alias.stub), "] = ")
            if utils.equivalent(\%args, \%alias_args) then
                lua:append("nomsu.COMPILE_ACTIONS[", repr(\%actions[1].stub), "]")
            else
                lua:append("function(")
                lua:concat_append(\%alias_args, ", ")
                lua:append(")\n    return nomsu.COMPILE_ACTIONS[", repr(\%actions[1].stub), "](")
                lua:concat_append(\%args, ", ")
                lua:append(")\nend")
            end
        end
        return lua
    end

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

compile [using %defs compile %body] to
    lua> ".."
        local lua = LuaCode(tree.source)
        lua:append(
            "local old_nomsu = nomsu\n",
            "local nomsu = table.fork(old_nomsu, {COMPILE_ACTIONS=table.fork(old_nomsu.COMPILE_ACTIONS)})")
        lua:append(nomsu:compile(\%defs))
        lua:append("\n")
        lua:append("local ret = nomsu:compile(tree)\n")
        lua:append("return ret")
        nomsu = table.fork(nomsu, {tree=\%body})
        local output = nomsu:run_lua(lua)
        return output

compile [local action %actions %body] to
    lua> ".."
        local fn_name = "A"..string.as_lua_id(\%actions[1].stub)
        local \%args = table.map(\%actions[1]:get_args(), function(a) return tostring(nomsu:compile(a)) end)
        local lua = LuaCode(tree.source, fn_name, " = ", \(compile as: %args -> %body))
        lua:add_free_vars({fn_name})
        for i=2,#\%actions do
            local alias = \%actions[i]
            local alias_name = "A"..string.as_lua_id(alias.stub)
            lua:add_free_vars({alias_name})
            local \%alias_args = table.map(alias:get_args(), function(a) return tostring(nomsu:compile(a)) end)
            lua:append("\n", alias_name, " = ")
            if utils.equivalent(\%args, \%alias_args) then
                lua:append(fn_name)
            else
                lua:append("function(")
                lua:concat_append(\%alias_args, ", ")
                lua:append(")\n    return ", fn_name, "(")
                lua:concat_append(\%args, ", ")
                lua:append(")\nend")
            end
        end
        return lua

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

compile [action %actions %body] to
    lua> ".."
        local lua = \(compile as: local action %actions %body)
        lua:remove_free_vars(table.map(\%actions, function(a) return "A"..string.as_lua_id(a.stub) end))
        return lua

compile [action %action] to
    Lua value "A\(%action.stub as lua id)"

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

compile [parse %actions as %body] to
    lua> ".."
        local replacements = {}
        for i,arg in ipairs(\%actions[1]:get_args()) do
            replacements[arg[1]] = tostring(nomsu:compile(arg))
        end
        local function make_tree(t)
            if not AST.is_syntax_tree(t) then
                return repr(t)
            elseif t.type ~= 'Var' then
                local args = {repr(tostring(t.source)), unpack(table.map(t, make_tree))}
                return t.type.."("..table.concat(args, ", ")..")"
            elseif replacements[t[1]] then
                return replacements[t[1]]
            else
                return t.type.."("..repr(tostring(t.source))..", "..repr(t[1].." \\0").."..string.format('%X', __MANGLE_INDEX))"
            end
        end
        local \%new_body = LuaCode(\%body.source,
            "__MANGLE_INDEX = (__MANGLE_INDEX or 0) + 1",
            "\nlocal tree = ", make_tree(\%body),
            "\nreturn nomsu:compile(tree)")
        return \(compile as: compile %actions to %new_body)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

compile [remove action %action] to
    Lua ".."
        A\(=lua "string.as_lua_id(\(%action.stub))") = nil

action [%tree as nomsu]
    =lua "nomsu:tree_to_nomsu(\%tree)"

action [%tree as inline nomsu]
    =lua "nomsu:tree_to_nomsu(\%tree, true)"

action [%tree as lua]
    =lua "nomsu:compile(\%tree)"

action [%tree as lua expr]
    lua> ".."
        local lua = nomsu:compile(\%tree)
        if not lua.is_value then
            nomsu:compile_error(\%tree, "Invalid thing to convert to lua expr:\n%s")
        end
        return lua

action [%tree as lua statements]
    =lua "nomsu:compile(\%tree):as_statements()"

action [%tree as lua return]
    =lua "nomsu:compile(\%tree):as_statements('return ')"

action [%var as lua identifier, %var as lua id]
    lua> ".."
        if type(\%var) == 'string' then return string.as_lua_id(\%var)
        elseif \%var.type == 'Var' then return string.as_lua_id(\%var[1])
        elseif \%var.type == 'Action' then return "A"..string.as_lua_id(\%var.stub)
        end

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    
compile [%tree with %t -> %replacement] to
    Lua value ".."
        \(%tree as lua expr):map(function(\(%t as lua expr))
            \(%replacement as lua return)
        end)

compile [declare locals in %code] to
    Lua value "\(%code as lua expr):declare_locals()"

compile [declare locals %locals in %code] to
    Lua value "\(%code as lua expr):declare_locals(\(%locals as lua expr))"

compile [add free vars %vars to %code] to
    Lua "\(%code as lua expr):add_free_vars(\(%vars as lua expr));"

compile [remove free vars %vars from %code] to
    Lua "\(%code as lua expr):remove_free_vars(\(%vars as lua expr));"

compile [%lua <-write %code, to %lua write %code] to: Lua "\(%lua as lua expr):append(\(%code as lua expr));"

compile [quote %s] to
    Lua value ".."
        ('"'..\(%s as lua expr):gsub("\\\\", "\\\\\\\\"):gsub("\n","\\\\n"):gsub('"', '\\\\"')..'"')
compile [type of %obj] to: Lua value "type(\(%obj as lua expr))"

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

compile [parse %text] to
    Lua value ".."
        nomsu:parse(NomsuCode("\("\(%text.source)")", \(%text as lua expr)))

compile [run %nomsu_code] to
    Lua value "nomsu:run(NomsuCode(\(quote "\(%nomsu_code.source)"), \(%nomsu_code as lua expr)))"

action [run tree %tree, %tree as value]
    lua> ".."
        if \%tree.type == 'Text' and #\%tree == 1 and type(\%tree[1]) == 'string' then
            return \%tree[1]
        end
        local lua = LuaCode(\%tree.source, "return ",nomsu:compile(\%tree))
        return nomsu:run_lua(lua)

compile [compile %block, compiled %block, %block compiled] to
    Lua value "nomsu:compile(\(%block as lua))"

# Return statement is wrapped in a do..end block because Lua is unhappy if you
    put code after a return statement, unless you wrap it in a block.
compile [return] to: Lua "do return; end"
compile [return %return_value] to: Lua "do return \(%return_value as lua expr); end"

# Literals
compile [yes] to: Lua value "true"
compile [no] to: Lua value "false"
compile [nothing, nil, null] to: Lua value "nil"