void QgsFieldExpressionWidget::expressionEdited( const QString expression )
{
  updateLineEditStyle( expression );
}
void QgsFieldExpressionWidget::expressionEdited( const QString& expression )
{
  updateLineEditStyle( expression );
  emit fieldChanged( expression, isValidExpression() );
}
void QgsExpressionLineEdit::expressionEdited( const QString& expression )
{
  updateLineEditStyle( expression );
  emit expressionChanged( expression );
}