expression: more comments and test to avoid differences between operators declaration and text values

Author: 3nids

src/core/qgsexpression.cpp

@@ -212,6 +212,7 @@ inline bool isNull( const QVariant& v ) { return v.isNull(); }
 
 const char* QgsExpression::BinaryOperatorText[] =
 {
+  // this must correspond (number and order of element) to the declaration of the enum BinaryOperator
   "OR", "AND",
   "=", "<>", "<=", ">=", "<", ">", "~", "LIKE", "NOT LIKE", "ILIKE", "NOT ILIKE", "IS", "IS NOT",
   "+", "-", "*", "/", "//", "%", "^",
@@ -220,6 +221,7 @@ const char* QgsExpression::BinaryOperatorText[] =
 
 const char* QgsExpression::UnaryOperatorText[] =
 {
+  // this must correspond (number and order of element) to the declaration of the enum UnaryOperator
   "NOT", "-"
 };
 

src/core/qgsexpression.h

@@ -210,11 +210,20 @@ class CORE_EXPORT QgsExpression
     */
     static double evaluateToDouble( const QString& text, const double fallbackValue );
 
+    /**
+     * @brief list of unary operators
+     * @note if any change is made here, the definition of QgsExpression::UnaryOperatorText[] must be adapted.
+     */
     enum UnaryOperator
     {
       uoNot,
       uoMinus,
     };
+
+    /**
+     * @brief list of binary operators
+     * @note if any change is made here, the definition of QgsExpression::BinaryOperatorText[] must be adapted.
+     */
     enum BinaryOperator
     {
       // logical

tests/src/core/testqgsexpression.cpp

@@ -468,6 +468,9 @@ class TestQgsExpression: public QObject
 
     void eval_precedence()
     {
+      QCOMPARE(QgsExpression::BinaryOperatorText[QgsExpression::boDiv],"/");
+      QCOMPARE(QgsExpression::BinaryOperatorText[QgsExpression::boConcat],"||");
+
       QgsExpression e0( "1+2*3" );
       QCOMPARE( e0.evaluate().toInt(), 7 );