Add missing help and show missing variables in editor

Author: nyalldawson

src/core/qgsexpression.cpp

@@ -4449,6 +4449,10 @@ void QgsExpression::initVariableHelp()
   gVariableHelpTexts.insert( "row_number", QCoreApplication::translate( "variable_help", "Stores the number of the current row." ) );
   gVariableHelpTexts.insert( "grid_number", QCoreApplication::translate( "variable_help", "Current grid annotation value." ) );
   gVariableHelpTexts.insert( "grid_axis", QCoreApplication::translate( "variable_help", "Current grid annotation axis (eg, 'x' for longitude, 'y' for latitude)." ) );
+
+  //symbol variables
+  gVariableHelpTexts.insert( "geometry_part_count", QCoreApplication::translate( "variable_help", "Number of parts in rendered feature's geometry." ) );
+  gVariableHelpTexts.insert( "geometry_part_num", QCoreApplication::translate( "variable_help", "Current geometry part number for feature being rendered." ) );
 }
 
 QString QgsExpression::variableHelpText( const QString &variableName, bool showValue, const QVariant &value )

src/gui/symbology-ng/qgssizescalewidget.cpp

@@ -116,6 +116,11 @@ static QgsExpressionContext _getExpressionContext( const void* context )
   if ( widget->layer() )
     expContext << QgsExpressionContextUtils::layerScope( widget->layer() );
 
+  expContext.lastScope()->addVariable( QgsExpressionContextScope::StaticVariable( "geometry_part_count", 1, true ) );
+  expContext.lastScope()->addVariable( QgsExpressionContextScope::StaticVariable( "geometry_part_num", 1, true ) );
+
+  expContext.setHighlightedVariables( QStringList() << "geometry_part_num" );
+
   return expContext;
 }
 

src/gui/symbology-ng/qgssymbollayerv2widget.cpp

@@ -75,9 +75,12 @@ static QgsExpressionContext _getExpressionContext( const void* context )
   if ( layer )
     expContext << QgsExpressionContextUtils::layerScope( layer );
 
+  expContext.lastScope()->addVariable( QgsExpressionContextScope::StaticVariable( "geometry_part_count", 1, true ) );
+  expContext.lastScope()->addVariable( QgsExpressionContextScope::StaticVariable( "geometry_part_num", 1, true ) );
+
   //TODO - show actual value
   expContext.setOriginalValueVariable( QVariant() );
-  expContext.setHighlightedVariables( QStringList() << QgsExpressionContext::EXPR_ORIGINAL_VALUE );
+  expContext.setHighlightedVariables( QStringList() << QgsExpressionContext::EXPR_ORIGINAL_VALUE << "geometry_part_count" << "geometry_part_num" );
 
   return expContext;
 }