fix build error and update sips

python/core/qgsexpression.sip

@@ -66,6 +66,8 @@ class QgsExpression
     //! @note added in 2.2
     static bool hasSpecialColumn( const QString& name );
 
+    static bool isValid( const QString& text, const QgsFields& fields, QString &errorMessage );
+
     void setScale( double scale );
 
     double scale();

python/gui/qgsfieldexpressionwidget.sip

@@ -20,6 +20,8 @@ class QgsFieldExpressionWidget : QWidget
     //! setFilters allows fitering according to the type of field
     void setFilters( QgsFieldProxyModel::Filters filters );
 
+    void setLeftHandButtonStyle( bool isLeft );
+
     //! currently used filter on list of fields
     QgsFieldProxyModel::Filters filters();
 
@@ -33,6 +35,17 @@ class QgsFieldExpressionWidget : QWidget
      */
     QString currentField( bool *isExpression = 0, bool *isValid = 0 );
 
+    /**
+      * Return true if the current expression is valid
+      */
+    bool isValidExpression( QString *expressionError = 0 );
+
+    bool isExpression();
+    /**
+      * Return the current text that is set in the expression area
+      */
+    QString currentText();
+
     //! Returns the currently used layer
     QgsVectorLayer* layer();
 
@@ -43,6 +56,8 @@ class QgsFieldExpressionWidget : QWidget
     //! fieldChanged signal with indication of the validity of the expression
     void fieldChanged( QString fieldName, bool isValid );
 
+    void returnPressed();
+
   public slots:
     //! set the layer used to display the fields and expression
     void setLayer( QgsVectorLayer* layer );

src/core/qgsexpression.cpp

@@ -1729,7 +1729,7 @@ bool QgsExpression::hasSpecialColumn( const QString& name )
   return gmSpecialColumns.contains( name );
 }
 
-bool QgsExpression::isValid( const QString &text, const QgsFields &fields, QString errorMessage )
+bool QgsExpression::isValid( const QString &text, const QgsFields &fields, QString &errorMessage )
 {
   QgsExpression exp( text );
   exp.prepare( fields );

src/core/qgsexpression.h

@@ -152,7 +152,7 @@ class CORE_EXPORT QgsExpression
     //! @note added in 2.2
     static bool hasSpecialColumn( const QString& name );
 
-    static bool isValid( const QString& text, const QgsFields& fields, QString errorMessage );
+    static bool isValid( const QString& text, const QgsFields& fields, QString &errorMessage );
 
     void setScale( double scale ) { mScale = scale; }
 

src/gui/qgsfieldexpressionwidget.cpp

@@ -87,9 +87,10 @@ QString QgsFieldExpressionWidget::currentText()
   return mCombo->currentText();
 }
 
-bool QgsFieldExpressionWidget::isValidExpression( QString& expressionError )
+bool QgsFieldExpressionWidget::isValidExpression( QString *expressionError )
 {
-  return QgsExpression::isValid( currentText(), layer()->pendingFields(), expressionError );
+  QString temp;
+  return QgsExpression::isValid( currentText(), layer()->pendingFields(), expressionError ? *expressionError : temp );
 }
 
 bool QgsFieldExpressionWidget::isExpression()

src/gui/qgsfieldexpressionwidget.h

@@ -77,11 +77,11 @@ class GUI_EXPORT QgsFieldExpressionWidget : public QWidget
     /**
       * Return true if the current expression is valid
       */
-    bool isValidExpression( QString& expressionError = QString() );
+    bool isValidExpression( QString *expressionError = 0 );
 
     bool isExpression();
     /**
-      * Retun the current text that is set in the expression area
+      * Return the current text that is set in the expression area
       */
     QString currentText();