From 343fe54f2cb79c99e1932889dd50053e1b803ec0 Mon Sep 17 00:00:00 2001
From: Marin Tomic <marin.tomic@memgraph.io>
Date: Thu, 4 Oct 2018 16:31:41 +0200
Subject: [PATCH] Move 'explain' to Cypher.g4 and add it to keyword list

Summary: Move explain to Cypher.g4 so MemgraphCypher contains only enterprise features. Also added `EXPLAIN` to keyword list because query `MATCH (explain) RETURN explain` wasn't working.

Reviewers: teon.banek

Reviewed By: teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D1632
---
 .../frontend/opencypher/grammar/Cypher.g4     |  7 +++++-
 .../opencypher/grammar/CypherLexer.g4         |  1 +
 .../opencypher/grammar/MemgraphCypher.g4      |  4 +---
 .../opencypher/grammar/MemgraphCypherLexer.g4 |  3 +--
 .../frontend/stripped_lexer_constants.hpp     | 24 +++++++++----------
 5 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/src/query/frontend/opencypher/grammar/Cypher.g4 b/src/query/frontend/opencypher/grammar/Cypher.g4
index ac7899e14..bb1d3eef9 100644
--- a/src/query/frontend/opencypher/grammar/Cypher.g4
+++ b/src/query/frontend/opencypher/grammar/Cypher.g4
@@ -23,7 +23,11 @@ cypher : statement ';'? EOF ;
 
 statement : query ;
 
-query : regularQuery ;
+query : regularQuery
+      | explainQuery
+      ;
+
+explainQuery : EXPLAIN regularQuery ;
 
 regularQuery : singleQuery ( cypherUnion )* ;
 
@@ -291,6 +295,7 @@ cypherKeyword : ALL
               | ELSE
               | END
               | ENDS
+              | EXPLAIN
               | EXTRACT
               | FALSE
               | FILTER
diff --git a/src/query/frontend/opencypher/grammar/CypherLexer.g4 b/src/query/frontend/opencypher/grammar/CypherLexer.g4
index aad481a36..ce4b06dc6 100644
--- a/src/query/frontend/opencypher/grammar/CypherLexer.g4
+++ b/src/query/frontend/opencypher/grammar/CypherLexer.g4
@@ -89,6 +89,7 @@ DISTINCT       : D I S T I N C T ;
 ELSE           : E L S E ;
 END            : E N D ;
 ENDS           : E N D S ;
+EXPLAIN        : E X P L A I N ;
 EXTRACT        : E X T R A C T ;
 FALSE          : F A L S E ;
 FILTER         : F I L T E R ;
diff --git a/src/query/frontend/opencypher/grammar/MemgraphCypher.g4 b/src/query/frontend/opencypher/grammar/MemgraphCypher.g4
index c11908966..a2935e1e8 100644
--- a/src/query/frontend/opencypher/grammar/MemgraphCypher.g4
+++ b/src/query/frontend/opencypher/grammar/MemgraphCypher.g4
@@ -1,4 +1,4 @@
-/* Memgraph specific part of Cypher grammar. */
+/* Memgraph specific part of Cypher grammar with enterprise features. */
 
 parser grammar MemgraphCypher ;
 
@@ -51,8 +51,6 @@ query : regularQuery
       | explainQuery
       ;
 
-explainQuery : EXPLAIN regularQuery ;
-
 authQuery : createRole
           | dropRole
           | showRoles
diff --git a/src/query/frontend/opencypher/grammar/MemgraphCypherLexer.g4 b/src/query/frontend/opencypher/grammar/MemgraphCypherLexer.g4
index 9accae45f..cbb97da34 100644
--- a/src/query/frontend/opencypher/grammar/MemgraphCypherLexer.g4
+++ b/src/query/frontend/opencypher/grammar/MemgraphCypherLexer.g4
@@ -1,4 +1,4 @@
-/* Memgraph specific Cypher reserved words. */
+/* Memgraph specific Cypher reserved words used for enterprise features. */
 
 /*
  * When changing this grammar make sure to update constants in
@@ -18,7 +18,6 @@ CLEAR          : C L E A R ;
 DATA           : D A T A ;
 DENY           : D E N Y ;
 DROP           : D R O P ;
-EXPLAIN        : E X P L A I N ;
 FOR            : F O R ;
 FROM           : F R O M ;
 GRANT          : G R A N T ;
diff --git a/src/query/frontend/stripped_lexer_constants.hpp b/src/query/frontend/stripped_lexer_constants.hpp
index ec22dc77a..07e6cd546 100644
--- a/src/query/frontend/stripped_lexer_constants.hpp
+++ b/src/query/frontend/stripped_lexer_constants.hpp
@@ -79,18 +79,18 @@ class Trie {
 const int kBitsetSize = 65536;
 
 const trie::Trie kKeywords = {
-    "union",    "all",   "optional",  "match",  "unwind",     "as",
-    "merge",    "on",    "create",    "set",    "detach",     "delete",
-    "remove",   "with",  "distinct",  "return", "order",      "by",
-    "skip",     "limit", "ascending", "asc",    "descending", "desc",
-    "where",    "or",    "xor",       "and",    "not",        "in",
-    "starts",   "ends",  "contains",  "is",     "null",       "case",
-    "when",     "then",  "else",      "end",    "count",      "filter",
-    "extract",  "any",   "none",      "single", "true",       "false",
-    "reduce",   "user",  "password",  "alter",  "drop",       "stream",
-    "streams",  "load",  "data",      "kafka",  "transform",  "batch",
-    "interval", "show",  "start",     "stop",   "size",       "topic",
-    "test"};
+    "union",    "all",    "optional",  "match",  "unwind",     "as",
+    "merge",    "on",     "create",    "set",    "detach",     "delete",
+    "remove",   "with",   "distinct",  "return", "order",      "by",
+    "skip",     "limit",  "ascending", "asc",    "descending", "desc",
+    "where",    "or",     "xor",       "and",    "not",        "in",
+    "starts",   "ends",   "contains",  "is",     "null",       "case",
+    "when",     "then",   "else",      "end",    "count",      "filter",
+    "extract",  "any",    "none",      "single", "true",       "false",
+    "reduce",   "user",   "password",  "alter",  "drop",       "stream",
+    "streams",  "load",   "data",      "kafka",  "transform",  "batch",
+    "interval", "show",   "start",     "stop",   "size",       "topic",
+    "test",     "explain"};
 
 // Unicode codepoints that are allowed at the start of the unescaped name.
 const std::bitset<kBitsetSize> kUnescapedNameAllowedStarts(std::string(