indentation parsing and if

moonscript.lua

@@ -5,6 +5,10 @@ require"util"
 require"lpeg"
 
 require"moonscript.compile"
+require"moonscript.dump"
+require"moonscript.data"
+
+local Stack = data.Stack
 
 local function count_indent(str)
 	local sum = 0
@@ -16,10 +20,11 @@ local function count_indent(str)
 end
 
 local R, S, V, P = lpeg.R, lpeg.S, lpeg.V, lpeg.P
-local C, Ct = lpeg.C, lpeg.Ct
+local C, Ct, Cmt = lpeg.C, lpeg.Ct, lpeg.Cmt
 
 local Space = S" \t"^0
-local Break = S"\n" + -1
+local Break = S"\n"
+local Stop = Break + -1
 local Indent = C(S"\t "^0) / count_indent
 local ArgDelim = "," * Space
 
@@ -53,6 +58,14 @@ function mark(name)
 	end
 end
 
+function got(what)
+	return function(...)
+		print("got "..tostring(what))
+		return true
+	end
+end
+
+
 function flatten(tbl)
 	if #tbl == 1 then
 		return tbl[1]
@@ -61,7 +74,7 @@ function flatten(tbl)
 end
 
 local build_grammar = wrap(function()
-	local err_msg = "Failed to compile, line:\n [%d] >> %s"
+	local err_msg = "Failed to compile, line:\n [%d] >> %s (%d)"
 	local line = 1
 	local function line_count(subject, pos, str)
 		for _ in str:gmatch("\n") do
@@ -71,18 +84,48 @@ local build_grammar = wrap(function()
 		return true
 	end
 
-	local Space = lpeg.Cmt(Space, line_count)
-	local Break = lpeg.Cmt(Break, line_count)
+	local Space = Cmt(Space, line_count)
+	local Break = Cmt(Break, line_count)
+
+	local _indent = Stack(0) -- current indent
+
+	local function check_indent(str, pos, indent)
+		return _indent:top() == indent
+	end
+
+	local function advance_indent(str, pos, indent)
+		if indent > _indent:top() then
+			_indent:push(indent)
+			return true
+		end
+	end
+
+	local function pop_indent(str, pos)
+		if not _indent:pop() then error("unexpected outdent") end
+		return true
+	end
+
+	local keywords = {}
+	local function key(word)
+		keywords[word] = true
+		return word * Space
+	end
 
 	local g = lpeg.P{
 		Block,
-		Block = Ct(Line^0),
-		Line = Ct(Funcall) * Break,
+		Block = Ct((Line)^0),
+		Line = Break + Cmt(Indent, check_indent) * (Ct(If) + Exp * Stop),
+		InBlock = #Cmt(Indent, advance_indent) * Block * OutBlock,
+		OutBlock = Cmt(P(""), pop_indent),
+
 		Funcall = Name * ArgList / mark"fncall",
+		If = key"if" * Exp * Break * InBlock / mark "if",
+
 		ArgList = Ct(Exp * (ArgDelim * Exp)^0),
 		Exp = Ct(Value * (FactorOp * Value)^0) / flatten,
 		Value = Funcall + Num + Name
 	}
+
 	return {
 		_g = Space * g * Space * -1,
 		match = function(self, str, ...)
@@ -95,7 +138,7 @@ local build_grammar = wrap(function()
 
 			local tree = self._g:match(str, ...)
 			if not tree then
-				return nil, err_msg:format(line, get_line(line))
+				return nil, err_msg:format(line, get_line(line), _indent:top())
 			end
 			return tree
 		end
@@ -105,20 +148,27 @@ end)
 
 local grammar = build_grammar()
 
+
+
 local program = [[
-if gogo bozango
-	print hello_world
+if two_dads
+	do something
+	if yum
+		heckyes 23
+
+print 2
+
+print dadas
+this is what a sentence does when you use it
 ]]
--- print hi + world + 2342
--- print 23424
--- ]]
 
 
 local tree, err = grammar:match(program)
 if not tree then error(err) end
 
-print(util.dump(tree))
--- print(compile.tree(tree))
+dump.tree(tree)
+print""
+print(compile.tree(tree))
 
 local program2 = [[
 if something

moonscript/compile.lua

@@ -2,13 +2,21 @@
 module("moonscript.compile", package.seeall)
 require "util"
 
+-- this doesn't work
 -- setmetatable(_M, {
 -- 	__call = setfenv(function(self, ...)
 -- 		compile(...)
 -- 	end, _G)
 -- })
 
+local indent_char = "  "
+
 local compilers = {
+	_indent = 0,
+	ichar = function(self)
+		return indent_char:rep(self._indent)
+	end,
+
 	fncall = function(self, node)
 		local _, name, args = unpack(node)
 		return name .. self:args(args)
@@ -20,6 +28,21 @@ local compilers = {
 		end
 		return "(" .. table.concat(values, ", ") .. ")"
 	end,
+	["if"] = function(self, node)
+		local _, cond, block = unpack(node)
+		return ("if %s then\n%s\n%send"):format(
+			self:value(cond), self:block(block, 1), self:ichar())
+	end,
+	block = function(self, node, inc)
+		if inc then self._indent = self._indent + inc end
+		local lines = {}
+		local i = self:ichar()
+		for _, ln in ipairs(node) do
+			table.insert(lines, i..self:value(ln))
+		end
+		if inc then self._indent = self._indent - inc end
+		return table.concat(lines, "\n")
+	end,
 	value = function(self, node)
 		if type(node) == "table" then 
 			local op = unpack(node)
@@ -35,7 +58,7 @@ _M.tree = function(tree)
 	for _, line in ipairs(tree) do
 		local op = line[1]
 		local fn = compilers[op]
-		if not fn then error("Unknown op: "..op) end
+		if not fn then error("Unknown op: "..tostring(op)) end
 		table.insert(buff, compilers[op](compilers, line))
 	end
 

moonscript/data.lua

@@ -0,0 +1,31 @@
+
+module("moonscript.data", package.seeall)
+
+local stack_t = {}
+local _stack_mt = { __index = stack_t, __tostring = function(self)
+	return "<Stack {"..table.concat(self, ", ").."}>"
+end}
+
+function stack_t:pop()
+	return table.remove(self)
+end
+
+function stack_t:push(value)
+	table.insert(self, value)
+	return value
+end
+
+function stack_t:top()
+	return self[#self]
+end
+
+function Stack(...)
+	local self = setmetatable({}, _stack_mt)
+
+	for _, v in ipairs{...} do
+		self:push(v)
+	end
+
+	return self
+end
+

moonscript/dump.lua

@@ -0,0 +1,23 @@
+
+module("moonscript.dump", package.seeall)
+
+local function flat_value(op, depth)
+	depth = depth or 1
+
+	if type(op) == "string" then return '"'..op..'"' end
+	if type(op) ~= "table" then return tostring(op) end
+	local items = {}
+	for _, item in ipairs(op) do
+		table.insert(items, flat_value(item, depth+1))
+	end
+
+	return "{"..table.concat(items, ", ").."}"
+end
+
+function tree(block, depth)
+	depth = depth or 0
+	for _, op in ipairs(block) do
+		print(flat_value(op))
+	end
+end
+