implicity return for some types, temp storage for unary expressions

moonscript/compile.lua

@@ -29,6 +29,8 @@ local moonlib = {
 	end
 }
 
+local must_return = data.Set{ 'parens', 'exp', 'value', 'string', 'table', 'fndef' }
+
 local compiler_index = {
 	push = function(self) self._scope:push{} end,
 	pop = function(self) self._scope:pop() end,
@@ -37,7 +39,7 @@ local compiler_index = {
 		self._indent = self._indent + amount
 	end,
 
-	pretty = function(self, tbl)
+	pretty = function(self, tbl, indent_front)
 		local out = {}
 		for _, line in ipairs(tbl) do
 			if type(line) == "table" then
@@ -48,7 +50,12 @@ local compiler_index = {
 				table.insert(out, line)
 			end
 		end
-		return table.concat(out, "\n"..self:ichar())
+
+		local block = table.concat(out, "\n"..self:ichar())
+		if indent_front then
+			block = self:ichar()..block
+		end
+		return block
 	end,
 
 	has_name = function(self, name)
@@ -181,24 +188,25 @@ local compiler_index = {
 		local out
 		if #block == 0 then
 			out = ("function(%s) end"):format(args)
-		elseif #block == 1 then
-			out = ("function(%s) %s end"):format(args, self:value(block[1]))
+		elseif #block == 1 and must_return[ntype(block[1])] then
+			out = ("function(%s) %s end"):format(args, self:block(block, true, 0))
 		else
 			out = ("function(%s)\n%s\n%send"):format(
-				args, self:block(block, 1), self:ichar())
+				args, self:block(block, true), self:ichar())
 		end
 
 		self:pop()
 		return out
 	end,
 
-	["if"] = function(self, node)
+	-- compile if
+	["if"] = function(self, node, return_value)
 		local cond, block = node[2], node[3]
 		local ichr = self:ichar()
 
 		local out = {
 			("if %s then"):format(self:value(cond)),
-			self:block(block, 1)
+			self:block(block, return_value)
 		}
 
 		for i = 4,#node do
@@ -213,7 +221,7 @@ local compiler_index = {
 			else
 				error("Unknown if clause: "..clause[1])
 			end
-			table.insert(out, self:block(block, 1))
+			table.insert(out, self:block(block, return_value))
 		end
 
 		table.insert(out, ichr.."end")
@@ -225,7 +233,8 @@ local compiler_index = {
 		local _, cond, block = unpack(node)
 		local ichr = self:ichar()
 
-		return ("while %s do\n%s\n%send"):format(self:value(cond), self:block(block, 1), ichr)
+		return ("while %s do\n%s\n%send"):format(self:value(cond),
+			self:block(block, nil, 1), ichr)
 	end,
 
 	name_list = function(self, node)
@@ -267,17 +276,25 @@ local compiler_index = {
 		}
 	end,
 
-	block = function(self, node, inc)
+	block = function(self, node, return_value, inc)
+		inc = inc or 1
+
 		self:push()
-		if inc then self:indent(inc) end
+		self:indent(inc)
 
 		local lines = {}
-		local i = self:ichar()
-		for _, ln in ipairs(node) do
-			table.insert(lines, i..self:value(ln))
+		local len = #node
+		for i=1,len do
+			local ln = node[i]
+			local value = self:stm(ln, return_value and i == len)
+			if type(value) == "table" then
+				for _, v in value do
+					table.insert(lines, value)
+				end
+			else
+				table.insert(lines, value)
+			end
 		end
-		if inc then self:indent(-inc) end
-		self:pop()
 
         -- add semicolons where they might be needed
         for i, left, k, right in itwos(lines) do
@@ -286,7 +303,12 @@ local compiler_index = {
             end
         end
 
-		return table.concat(lines, "\n")
+		local out = self:pretty(lines, true)
+
+		self:indent(-inc)
+		self:pop()
+
+		return out
 	end,
 
 	table = function(self, node)
@@ -376,18 +398,35 @@ local compiler_index = {
 		return delim..inner..(delim_end or delim)
 	end,
 
-	value = function(self, node)
+	value = function(self, node, ...)
+		if return_value == nil then return_value = true end
+
 		if type(node) == "table" then 
 			local fn = self[node[1]]
 			if not fn then
 				error("Unknown op: "..tostring(node[1]))
 			end
-			return fn(self, node)
+			return fn(self, node, ...)
 		end
 
 		return node
 	end,
 
+    -- has no return value, meant to be on line of it's own
+    stm = function(self, node, return_value)
+        local value = self:value(node, return_value)
+
+        if must_return[ntype(node)] then
+			if return_value then
+				return "return "..value
+			else
+				return self:value({"assign", {"_"}, {value}}, false)
+			end
+        end
+
+        return value
+    end,
+
 	minus = function(self, node)
 		local _, value = unpack(node)
 		return "-"..self:value(value)
@@ -428,7 +467,7 @@ end
 
 function tree(tree)
 	local compiler = build_compiler()
-    return compiler:block(tree)
+    return compiler:block(tree, false, 0)
 end
 
 

moonscript/data.lua

@@ -29,3 +29,11 @@ function Stack(...)
 	return self
 end
 
+function Set(items)
+	local self = {}
+	for _,item in ipairs(items) do
+		self[item] = true
+	end
+	return self
+end
+

tests/outputs/assign.lua

@@ -1,6 +1,6 @@
-function()
+local _ = function()
   local joop = 2302
-  function(hi)
+  return function(hi)
     local d = 100
     hi = 1021
     local a, b, c = 1, 2, 3

tests/outputs/cond.lua

@@ -1,25 +1,25 @@
 local you_cool = false
 if cool then
   if you_cool then
-    one
+    local _ = one
   else
     if eatdic then
-      yeah
+      local _ = yeah
     else
-      two
-      three
+      local _ = two
+      _ = three
     end
   end
 else
-  no
+  local _ = no
 end
 if cool then
-  no
+  local _ = no
 end
 if cool then
-  no
+  local _ = no
 else
-  yes
+  local _ = yes
 end
 if cool then
   wow(cool)
@@ -29,12 +29,12 @@ end
 if working then
   if cool then
     if cool then
-      okay
+      local _ = okay
     else
-      what
+      local _ = what
     end
   else
-    nah
+    local _ = nah
   end
 end
 while true do
@@ -46,7 +46,7 @@ while 5 + 5 do
 end
 while also do
   i(work(too))
-  "okay"
+  local _ = "okay"
 end
 if yeah then
   no(day)

tests/outputs/lists.lua

@@ -62,13 +62,17 @@ end)();
   return tmp
 end)()
 require("util")
-local dump = function(x) print(util.dump(x)) end
+local dump = function(x)
+  print(util.dump(x))
+end
 local range = function(count)
   local i = 0
-  return(coroutine.wrap(function() while i < count do
-    coroutine.yield(i)
-    i = i + 1
-  end end))
+  return(coroutine.wrap(function()
+    while i < count do
+      coroutine.yield(i)
+      i = i + 1
+    end
+  end))
 end
 dump((function()
   local tmp = {}

tests/outputs/syntax.lua

@@ -1,13 +1,19 @@
-local x = function() print(what) end
-function() end
-function() function() function() end end end
+local x = function()
+  print(what)
+end
+local _ = function() end
+_ = function() return function() return function() end end end
 go(to(the(barn)))
-open(function() the(function() door end) end)
+open(function()
+  the(function()   return door end)
+end)
 open(function()
   the(door)
-  local hello = function() my(func) end
+  local hello = function()
+    my(func)
+  end
 end)
-local h = function() hi end
+local h = function() return hi end
 eat(function() end, world)
 local a = 1 + 2 * 3 / 6
 a = another
@@ -15,7 +21,7 @@ local bunch, go, here = world
 func(arg1, arg2, another, arg3)
 here = function() end
 local we = yeah
-local the, different = function() approach end, yeah
+local the, different = function() return approach end, yeah
 dad()
 dad(lord)
 hello(one, two)();
@@ -34,25 +40,31 @@ yeah = ((1 + 5) * 3) / 2
 yeah = ((1 + 5) * 3) / 2 + i % 100
 local whoa = (1 + 2) * (3 + 4) * (4 + 5);
 (function() end)()
-return(5 + function() 4 + 2 end)
-return(5 + (function() 4 end) + 2)
+return(5 + function() return 4 + 2 end)
+return(5 + (function() return 4 end) + 2)
 print(5 + function()
-  34
+  _ = 34
   good(nads)
 end)
 something('else', "ya")
 something('else')
 something("else")
 here(we)("go")[12123]
-local something = { test = 12323, what = function() print("hello world") end }
+local something = { test = 12323, what = function()
+    print("hello world")
+  end }
 print(something.test)
 local frick = { hello = "world" }
 local argon = { num = 100, world = function(self)
     print(self.num)
-    return({ something = function() print("hi from something") end })
+    return({ something = function()
+        print("hi from something")
+      end })
   end, somethin = function(self,str)
     print("string is", str)
-    return({ world = function(a,b) print("sum", a + b) end })
+    return({ world = function(a,b)
+        print("sum", a + b)
+      end })
   end }
 something.what()
 argon:world().something()
@@ -70,19 +82,21 @@ end)()
 if cool then
   print("hello")
 else
-  cool
+  _ = cool
 end
 print("nutjob")
 if hello then
-  343
+  _ = 343
 end
 if cool then
   print("what")
 else
-  cool
+  _ = cool
 end
 local arg = { ... }
-x = function(...) dump({ ... }) end
+x = function(...)
+  dump({ ... })
+end
 x = not true
 local y = not (5 + 5)
 y = #"hello"