From 66804a628149ad3d0272b3363cb4c28e6aeea854 Mon Sep 17 00:00:00 2001
From: javrucebo <javrucebo@pafuxel.de>
Date: Mon, 22 Jan 2018 18:54:52 +0100
Subject: [PATCH] Allow '==' to be parsed as equal operator in expressions.
 SQLite allows for this and it is in the same spirit as allowing both != and
 <> for non equality. (see https://sqlite.org/lang_expr.html#collateop)

---
 src/parser/bison_parser.y |  1 +
 src/parser/flex_lexer.l   |  4 +++-
 test/select_tests.cpp     | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/src/parser/bison_parser.y b/src/parser/bison_parser.y
index 0d98897..99c0fa0 100755
--- a/src/parser/bison_parser.y
+++ b/src/parser/bison_parser.y
@@ -814,6 +814,7 @@ exists_expr:
 
 comp_expr:
 		operand '=' operand			{ $$ = Expr::makeOpBinary($1, kOpEquals, $3); }
+	|	operand EQUALS operand			{ $$ = Expr::makeOpBinary($1, kOpEquals, $3); }
 	|	operand NOTEQUALS operand	{ $$ = Expr::makeOpBinary($1, kOpNotEquals, $3); }
 	|	operand '<' operand			{ $$ = Expr::makeOpBinary($1, kOpLess, $3); }
 	|	operand '>' operand			{ $$ = Expr::makeOpBinary($1, kOpGreater, $3); }
diff --git a/src/parser/flex_lexer.l b/src/parser/flex_lexer.l
index 66f3552..f39d0ed 100644
--- a/src/parser/flex_lexer.l
+++ b/src/parser/flex_lexer.l
@@ -175,7 +175,9 @@ ON			TOKEN(ON)
 OR			TOKEN(OR)
 TO			TOKEN(TO)
 
-"!="		TOKEN(NOTEQUALS)
+                /* Allow =/== see https://sqlite.org/lang_expr.html#collateop */
+"=="		TOKEN(EQUALS)             
+"!=" 		TOKEN(NOTEQUALS)
 "<>" 		TOKEN(NOTEQUALS)
 "<="		TOKEN(LESSEQ)
 ">="		TOKEN(GREATEREQ)
diff --git a/test/select_tests.cpp b/test/select_tests.cpp
index 3197a31..ddf2366 100644
--- a/test/select_tests.cpp
+++ b/test/select_tests.cpp
@@ -347,3 +347,42 @@ TEST(SelectColumnOrder) {
   ASSERT_STREQ(stmt->fromTable->list->at(2)->alias, "c");
   ASSERT_STREQ(stmt->fromTable->list->at(3)->alias, "d");
 }
+
+TEST(Operators) {
+  SelectStatement* stmt;
+  SQLParserResult result;
+
+  SQLParser::parse("SELECT * FROM foo where a =  1; \
+		    SELECT * FROM foo where a == 1; \
+		    SELECT * FROM foo where a != 1; \
+		    SELECT * FROM foo where a <> 1; \
+		    SELECT * FROM foo where a >  1; \
+		    SELECT * FROM foo where a <  1; \
+		    SELECT * FROM foo where a >= 1; \
+		    SELECT * FROM foo where a <= 1;", &result);
+
+  stmt = (SelectStatement*) result.getStatement(0);
+  ASSERT_EQ(stmt->whereClause->opType, kOpEquals);
+
+  stmt = (SelectStatement*) result.getStatement(1);
+  ASSERT_EQ(stmt->whereClause->opType, kOpEquals);
+
+  stmt = (SelectStatement*) result.getStatement(2);
+  ASSERT_EQ(stmt->whereClause->opType, kOpNotEquals);
+
+  stmt = (SelectStatement*) result.getStatement(3);
+  ASSERT_EQ(stmt->whereClause->opType, kOpNotEquals);
+
+  stmt = (SelectStatement*) result.getStatement(4);
+  ASSERT_EQ(stmt->whereClause->opType, kOpGreater);
+
+  stmt = (SelectStatement*) result.getStatement(5);
+  ASSERT_EQ(stmt->whereClause->opType, kOpLess);
+
+  stmt = (SelectStatement*) result.getStatement(6);
+  ASSERT_EQ(stmt->whereClause->opType, kOpGreaterEq);
+
+  stmt = (SelectStatement*) result.getStatement(7);
+  ASSERT_EQ(stmt->whereClause->opType, kOpLessEq);
+}
+