revert strange return

src/parser/parser.yy

@@ -1644,6 +1644,14 @@ yield_sentence
         s->setWhereClause($4);
         $$ = s;
     }
+    | KW_RETURN yield_columns {
+        auto *s = new YieldSentence($2);
+        $$ = s;
+    }
+    | KW_RETURN KW_DISTINCT yield_columns {
+        auto *s = new YieldSentence($3, true);
+        $$ = s;
+    }
     ;
 
 unwind_clause
@@ -1720,10 +1728,7 @@ reading_with_clauses
     ;
 
 match_sentence
-    : match_return {
-        $$ = new MatchSentence(new MatchClauseList(), $1);
-    }
-    | reading_clauses match_return {
+    : reading_clauses match_return {
         $$ = new MatchSentence($1, $2);
     }
     | reading_with_clauses match_return {

tests/tck/features/set/Set.feature

@@ -75,12 +75,21 @@ Feature: Set Test
       | a |
       | 1 |
       | 2 |
-    # cypher doesn't support intersect
+    # The standalone return statement is not a cypher statement but a ngql statement in nebula...
+    # So it can't be mixed with other cypher statements
     When executing query:
       """
       UNWIND [1,2] AS a RETURN a
       INTERSECT
-      RETURN 2 AS a
+      RETURN a
+      """
+    Then a SyntaxError should be raised at runtime:
+    When executing query:
+      """
+      UNWIND [1,2] AS a RETURN a
+      INTERSECT
+      WITH 2 AS a
+      RETURN a
       """
     Then the result should be, in any order:
       | a |
@@ -89,7 +98,8 @@ Feature: Set Test
       """
       UNWIND [1,2,3] AS a RETURN a, 100
       INTERSECT
-      RETURN 2 AS a, 100
+      WITH 2 AS a
+      RETURN a, 100
       """
     Then the result should be, in any order:
       | a | 100 |
@@ -291,7 +301,8 @@ Feature: Set Test
       """
       UNWIND [1,2,3] AS a RETURN a
       MINUS
-      RETURN 4 AS a
+      WITH 4 AS a
+      RETURN a
       """
     Then the result should be, in any order, with relax comparison:
       | a |
@@ -302,7 +313,8 @@ Feature: Set Test
       """
       UNWIND [1,2,3] AS a RETURN a
       MINUS
-      RETURN 2 AS a
+      WITH 2 AS a
+      RETURN a
       """
     Then the result should be, in any order, with relax comparison:
       | a |

tests/tck/features/yield/return.feature

@@ -1,7 +1,7 @@
 # Copyright (c) 2020 vesoft inc. All rights reserved.
 #
 # This source code is licensed under Apache 2.0 License.
-Feature: Return
+Feature: Return. A standalone return sentence is actually a yield sentence
 
   Background:
     Given a graph with space named "nba"
@@ -21,6 +21,22 @@ Feature: Return
     Then the result should be, in any order:
       | (1+1) | "1+1" | (INT)3.14 | (STRING)(1+1) | (STRING)true |
       | 2     | "1+1" | 3         | "2"           | "true"       |
+    When executing query:
+      """
+      GO FROM "Tony Parker" OVER like YIELD id($$) AS vid | RETURN $-.vid AS dst
+      """
+    Then the result should be, in any order, with relax comparison:
+      | dst                 |
+      | "LaMarcus Aldridge" |
+      | "Manu Ginobili"     |
+      | "Tim Duncan"        |
+    When executing query:
+      """
+      FETCH PROP ON player "Tony Parker" YIELD player.age as age | RETURN $-.age + 100 AS age
+      """
+    Then the result should be, in any order, with relax comparison:
+      | age |
+      | 136 |
 
   Scenario: hash call
     When executing query:
@@ -79,4 +95,4 @@ Feature: Return
       """
       RETURN name
       """
-    Then a SemanticError should be raised at runtime: Alias used but not defined: `name'
+    Then a SemanticError should be raised at runtime: Invalid label identifiers: name