comprehension decorator, non return value compile for comprehension

moonscript/compile.lua

@@ -43,8 +43,14 @@ local moonlib = {
 	end
 }
 
+-- these are always expressions, never statements, must be sent into temp variable
 local must_return = data.Set{ 'parens', 'exp', 'value', 'string', 'table', 'fndef' }
 
+-- make sure there are no block levels statements in expression
+local function validate_expression(block)
+	-- need to annotate blocks? how do I know where expressions are
+end
+
 local compiler_index = {
 	push = function(self) self._scope:push{} end,
 	pop = function(self) self._scope:pop() end,
@@ -264,25 +270,29 @@ local compiler_index = {
 		return table.concat(self:values(node), ", ")
 	end,
 
-	comprehension = function(self, node)
+	-- need to get tmp name instead of using tmp
+	comprehension = function(self, node, return_value)
 		local _, exp, clauses = unpack(node)
-		local insert = { ("table.insert(tmp, %s)"):format(self:value(exp)) }
+
+		local action = return_value
+			and { ("table.insert(tmp, %s)"):format(self:value(exp)) }
+			or { self:stm(exp) }
 
 		for i = #clauses,1,-1 do
 			local c = clauses[i]
 
 			if "for" == c[1] then
 				local _, names, iter = unpack(c)
-				insert = {
+				action = {
 					("for %s in %s do"):format(self:name_list(names), self:value(iter)),
-					insert,
+					action,
 					"end"
 				}
 			elseif "when" == c[1] then
 				local _, when = unpack(c)
-				insert = {
+				action = {
 					("if %s then"):format(self:value(when)),
-					insert,
+					action,
 					"end"
 				}
 			else
@@ -290,13 +300,17 @@ local compiler_index = {
 			end
 		end
 
+		if return_value then
 			return self:pretty{
 				"(function()",
 					{ "local tmp = {}", },
-				insert,
+					action,
 					{ "return tmp" },
 				"end)()"
 			}
+		else
+			return self:pretty(action)
+		end
 	end,
 
 	-- returns list of compiled statements
@@ -430,7 +444,7 @@ local compiler_index = {
 		return delim..inner..(delim_end or delim)
 	end,
 
-	value = function(self, node, ...)
+	value = function(self, node, return_value, ...)
 		if return_value == nil then return_value = true end
 
 		if type(node) == "table" then 
@@ -438,7 +452,7 @@ local compiler_index = {
 			if not fn then
 				error("Unknown op: "..tostring(node[1]))
 			end
-			return fn(self, node, ...)
+			return fn(self, node, return_value, ...)
 		end
 
 		return node

moonscript/parse.lua

@@ -191,6 +191,23 @@ local build_grammar = wrap(function()
 		return stm
 	end
 
+	local function wrap_decorator(stm, dec)
+		if not dec then return stm end
+
+		local arg = {stm, dec}
+
+		if dec[1] == "if" then
+			local _, cond, fail = unpack(dec)
+			if fail then fail = {"else", {fail}} end
+			stm = {"if", cond, {stm}, fail}
+		elseif dec[1] == "comprehension" then
+			local _, clauses = unpack(dec)
+			stm = {"comprehension", stm, clauses}
+		end
+
+		return stm
+	end
+
 	local function check_lua_string(str, pos, right, left)
 		return #left == #right
 	end
@@ -201,8 +218,11 @@ local build_grammar = wrap(function()
 		Block = Ct(Line * (Break^1 * Line)^0),
 		Line = Cmt(Indent, check_indent) * Statement + _Space * Comment,
 
-		Statement = (Import + If + While + Exp * Space) *
-			(key"if" * Exp * (key"else" * Exp)^-1 * Space / mark"if")^-1 / wrap_if,
+		Statement = (Import + If + While + Exp * Space) * (
+				-- statement decorators
+				key"if" * Exp * (key"else" * Exp)^-1 * Space / mark"if" +
+				CompInner / mark"comprehension"
+			)^-1 / wrap_decorator,
 
 		Body = Break * InBlock + Ct(Statement),
 
@@ -225,7 +245,9 @@ local build_grammar = wrap(function()
 			Ct((key"for" * Ct(NameList) * key"in" * Exp / mark"for") * CompClause^0) *
 			sym"]" / mark"comprehension",
 
-		CompClause = key"for" * Ct(NameList) * key"in" * Exp / mark"for" + key"when" * Exp / mark"when",
+		CompInner = Ct(CompFor * CompClause^0),
+		CompFor = key"for" * Ct(NameList) * key"in" * Exp / mark"for",
+		CompClause = CompFor + key"when" * Exp / mark"when",
 
 		Assign = Ct(AssignableList) * sym"=" * Ct(TableBlock + ExpList) / mark"assign",
 

tests/inputs/lists.moon

@@ -30,3 +30,12 @@ dump [{x, y} for x in range 5 when x > 2 for y in range 5]
 
 things = [x + y for x in range 10 when x > 5 for y in range 10 when y > 7]
 
+print x,y for x in ipairs{1,2,4} for y in ipairs{1,2,3} when x != 2
+
+print "hello", x for x in items
+
+[x for x in x]
+x = [x for x in x]
+
+print x,y for x in ipairs{1,2,4} for y in ipairs{1,2,3} when x != 2
+

tests/inputs/syntax.moon

@@ -131,3 +131,5 @@ y = not(5+5)
 y = #"hello"
 
 x = #{#{},#{1},#{1,2}}
+
+

tests/outputs/lists.lua

@@ -24,16 +24,12 @@ local mm = (function()
     table.insert(tmp, self.x)
   end
   return tmp
-end)();
-(function()
-  local tmp = {}
+end)()
 for z in ipairs(items) do
   if z > 4 then
-      table.insert(tmp, z)
+    local _ = z
   end
 end
-  return tmp
-end)()
 local rad = (function()
   local tmp = {}
   for a in ipairs({
@@ -49,18 +45,14 @@ local rad = (function()
     end
   end
   return tmp
-end)();
-(function()
-  local tmp = {}
+end)()
 for z in items do
   for j in list do
     if z > 4 then
-        table.insert(tmp, z)
+      _ = z
     end
   end
 end
-  return tmp
-end)()
 require("util")
 local dump = function(x) print(util.dump(x)) end
 local range = function(count)
@@ -103,3 +95,30 @@ local things = (function()
   end
   return tmp
 end)()
+for x in ipairs({ 1, 2, 4 }) do
+  for y in ipairs({ 1, 2, 3 }) do
+    if x ~= 2 then
+      print(x, y)
+    end
+  end
+end
+for x in items do
+  print("hello", x)
+end
+for x in x do
+  _ = x
+end
+local x = (function()
+  local tmp = {}
+  for x in x do
+    table.insert(tmp, x)
+  end
+  return tmp
+end)()
+for x in ipairs({ 1, 2, 4 }) do
+  for y in ipairs({ 1, 2, 3 }) do
+    if x ~= 2 then
+      print(x, y)
+    end
+  end
+end

tests/outputs/syntax.lua

@@ -71,8 +71,6 @@ x = -(function()
 end)()
 if cool then
   print("hello")
-else
-  _ = cool
 end
 print("nutjob")
 if hello then
@@ -81,7 +79,7 @@ end
 if cool then
   print("what")
 else
-  _ = cool
+  _ = whack
 end
 local arg = { ... }
 x = function(...) dump({ ... }) end