expression can be used inside slide boundaries, fixes #233

Author: leafo

moonscript/parse.lua

@@ -155,7 +155,7 @@ local build_grammar = wrap_env(debug_grammar, function(root)
     SimpleValue = If + Unless + Switch + With + ClassDecl + ForEach + For + While + Cmt(Do, check_do) + sym("-") * -SomeSpace * Exp / mark("minus") + sym("#") * Exp / mark("length") + sym("~") * Exp / mark("bitnot") + key("not") * Exp / mark("not") + TblComprehension + TableLit + Comprehension + FunLit + Num,
     ChainValue = (Chain + Callable) * Ct(InvokeArgs ^ -1) / join_chain,
     Value = pos(SimpleValue + Ct(KeyValueList) / mark("table") + ChainValue + String),
-    SliceValue = SimpleValue + ChainValue,
+    SliceValue = Exp,
     String = Space * DoubleString + Space * SingleString + LuaString,
     SingleString = simple_string("'"),
     DoubleString = simple_string('"', true),

moonscript/parse.moon

@@ -211,7 +211,7 @@ build_grammar = wrap_env debug_grammar, (root) ->
       ChainValue +
       String)
 
-    SliceValue: SimpleValue + ChainValue
+    SliceValue: Exp
 
     String: Space * DoubleString + Space * SingleString + LuaString
     SingleString: simple_string("'")

spec/inputs/comprehension.moon

@@ -42,5 +42,11 @@ hi = {hello,world for {:hello, :world} in *things}
 
 ok(a,b,c) for {a,b,c} in things
 
+--
+
+[item for item in *items[1 + 2,3+4]]
+[item for item in *items[hello! * 4, 2 - thing[4]]]
+
+
 
 nil

spec/outputs/comprehension.lua

@@ -247,4 +247,14 @@ for _des_0 in things do
   a, b, c = _des_0[1], _des_0[2], _des_0[3]
   ok(a, b, c)
 end
+local _max_0 = 3 + 4
+for _index_0 = 1 + 2, _max_0 < 0 and #items + _max_0 or _max_0 do
+  local item = items[_index_0]
+  _ = item
+end
+local _max_1 = 2 - thing[4]
+for _index_0 = hello() * 4, _max_1 < 0 and #items + _max_1 or _max_1 do
+  local item = items[_index_0]
+  _ = item
+end
 return nil