fix optional field_list in RecordExpression

Author: barakber

language-powerquery-ast/src/Language/PowerQuery/AST/AST.hs

@@ -146,8 +146,8 @@ data UnaryExpression annotation
 -- 12.2.3.10 Primary expression
 data PrimaryExpression annotation
     = LiteralPE        (LiteralExpression annotation)
-    | ListPE          (ListExpression annotation)
-    | RecordPE        (RecordExpression annotation)
+    | ListPE           (ListExpression annotation)
+    | RecordPE         (RecordExpression annotation)
     | IdentifierPE     (IdentifierExpression annotation)
     | SectionAccessPE  (SectionAccessExpression annotation)
     | ParenthesizedPE  (ParenthesizedExpression annotation)
@@ -226,7 +226,7 @@ data Item annotation
 -- 12.2.3.18 Record expression
 data RecordExpression annotation
     = RecordExpression
-    { _recordExpression_fieldList  :: !([Field annotation])
+    { _recordExpression_fieldList  :: !(Maybe [Field annotation])
     , _recordExpression_annotation :: !(Maybe annotation)
     }
     deriving (Show, Read, Eq, Data, Typeable, Generic)

language-powerquery/src/Language/PowerQuery/Lexer.x

@@ -191,7 +191,7 @@ powerquery :-
   <0> $whitespace+  { skip }
 
   -- 12.1.2 - Comment
-  <0> @single_line_comment { mkL CommentT }
+  <0> @single_line_comment ;
 
   --==========
   -- 12.1.5 - number-literal -- TODO

language-powerquery/src/Language/PowerQuery/Parser.y

@@ -429,8 +429,8 @@ list_expression
 
 item_list__opt :: { Maybe [Item Annotation] }
 item_list__opt
-    : item_list   { Just $1 }
-    | {- empty -} { Nothing }
+    : item_list     { Just $1 }
+    | {- empty -}   { Nothing }
 
 item_list :: { [Item Annotation] }
 item_list
@@ -445,7 +445,12 @@ item
 -- 12.2.3.18 - Record expression
 record_expression :: { RecordExpression Annotation }
 record_expression
-    : '[' field_list ']' { RecordExpression $2 (Just Annotation) }
+    : '[' field_list__opt ']' { RecordExpression $2 (Just Annotation) }
+
+field_list__opt :: { Maybe [Field Annotation] }
+field_list__opt
+    : field_list  { Just $1 }
+    | {- empty -} { Nothing }
 
 field_list :: { [Field Annotation] }
 field_list