src/app/qgslabelinggui.cpp

@@ -495,7 +495,7 @@ void QgsLabelingGui::showExpressionDialog()
   dlg.setWindowTitle( tr( "Expression based label" ) );
   if ( dlg.exec() == QDialog::Accepted )
   {
-    QString expression =  dlg.expressionBuilder()->getExpressionString();
+    QString expression =  dlg.getExpressionText();
     //Only add the expression if the user has entered some text.
     if ( !expression.isEmpty() )
     {

src/gui/CMakeLists.txt

@@ -75,6 +75,7 @@ qgsludialog.cpp
 qgssearchquerybuilder.cpp
 qgsexpressionbuilderwidget.cpp
 qgsexpressionbuilderdialog.cpp
+qgsexpressionhighlighter.cpp
 qgsquerybuilder.cpp
 )
 
@@ -135,6 +136,7 @@ qgsprojectbadlayerguihandler.h
 qgslonglongvalidator.h
 qgssearchquerybuilder.h
 qgsexpressionbuilderwidget.h
+qgsexpressionhighlighter.h
 qgsquerybuilder.h
 )
 
@@ -170,6 +172,7 @@ qgsattributeeditor.h
 qgsfieldvalidator.h
 qgsexpressionbuilderwidget.h
 qgsexpressionbuilderdialog.h
+qgsexpressionhighlighter.h
 
 attributetable/qgsattributetablemodel.h
 attributetable/qgsattributetablememorymodel.h

src/gui/qgsexpressionbuilderdialog.cpp

@@ -42,6 +42,11 @@ void QgsExpressionBuilderDialog::setExpressionText( QString text )
   builder->setExpressionString( text );
 }
 
+QString QgsExpressionBuilderDialog::getExpressionText()
+{
+  return builder->getExpressionString();
+}
+
 void QgsExpressionBuilderDialog::closeEvent( QCloseEvent *event )
 {
   QDialog::closeEvent( event );

src/gui/qgsexpressionbuilderdialog.h

@@ -19,6 +19,9 @@
 #include <QDialog>
 #include "ui_qgsexpressionbuilderdialogbase.h"
 
+/** A generic dialog for building expression strings
+  * @remarks This class also shows an example on how to use QgsExpressionBuilderWidget
+  */
 class GUI_EXPORT QgsExpressionBuilderDialog : public QDialog, private Ui::QgsExpressionBuilderDialogBase
 {
   public:
@@ -29,6 +32,8 @@ class GUI_EXPORT QgsExpressionBuilderDialog : public QDialog, private Ui::QgsExp
 
     void setExpressionText( QString text );
 
+    QString getExpressionText();
+
   protected:
     /**
      * Handle closing of the window

src/gui/qgsexpressionbuilderwidget.cpp

@@ -33,6 +33,7 @@ QgsExpressionBuilderWidget::QgsExpressionBuilderWidget( QWidget *parent )
   // The open and save button are for future.
   btnOpen->hide();
   btnSave->hide();
+  highlighter = new QgsExpressionHighlighter( txtExpressionString->document() );
 
   mModel = new QStandardItemModel( );
   mProxyModel = new QgsExpressionItemSearchProxy();
@@ -41,15 +42,11 @@ QgsExpressionBuilderWidget::QgsExpressionBuilderWidget( QWidget *parent )
 
   expressionTree->setContextMenuPolicy( Qt::CustomContextMenu );
   connect( expressionTree, SIGNAL( customContextMenuRequested( const QPoint & ) ), this, SLOT( showContextMenu( const QPoint & ) ) );
-  connect( btnPlusPushButton, SIGNAL( pressed() ), this, SLOT( operatorButtonClicked() ) );
-  connect( btnMinusPushButton, SIGNAL( pressed() ), this, SLOT( operatorButtonClicked() ) );
-  connect( btnDividePushButton, SIGNAL( pressed() ), this, SLOT( operatorButtonClicked() ) );
-  connect( btnMultiplyPushButton, SIGNAL( pressed() ), this, SLOT( operatorButtonClicked() ) );
-  connect( btnExpButton, SIGNAL( pressed() ), this, SLOT( operatorButtonClicked() ) );
-  connect( btnConcatButton, SIGNAL( pressed() ), this, SLOT( operatorButtonClicked() ) );
-  connect( btnOpenBracketPushButton, SIGNAL( pressed() ), this, SLOT( operatorButtonClicked() ) );
-  connect( btnCloseBracketPushButton, SIGNAL( pressed() ), this, SLOT( operatorButtonClicked() ) );
 
+  foreach (QPushButton* button, this->mOperatorsGroupBox->findChildren<QPushButton *>())
+  {
+      connect( button, SIGNAL( pressed() ), this, SLOT( operatorButtonClicked() ) );
+  }
 
   // TODO Can we move this stuff to QgsExpression, like the functions?
   registerItem( tr( "Operators" ), "+", " + " );
@@ -152,12 +149,22 @@ void QgsExpressionBuilderWidget::loadFieldNames()
     return;
 
   const QgsFieldMap fieldMap = mLayer->pendingFields();
-  QgsFieldMap::const_iterator fieldIt = fieldMap.constBegin();
-  for ( ; fieldIt != fieldMap.constEnd(); ++fieldIt )
+  loadFieldNames( fieldMap );
+}
+
+void QgsExpressionBuilderWidget::loadFieldNames( QgsFieldMap fields )
+{
+  if ( fields.isEmpty() )
+      return;
+
+  QStringList fieldNames;
+  foreach( QgsField field, fields )
   {
-    QString fieldName = fieldIt.value().name();
-    registerItem( tr( "Fields" ), fieldName, " " + fieldName + " ", "", QgsExpressionItem::Field );
+    QString fieldName = field.name();
+    fieldNames << fieldName;
+    registerItem( tr( "Fields" ), fieldName, " \"" + fieldName + "\" ", "", QgsExpressionItem::Field );
   }
+  highlighter->addFields( fieldNames );
 }
 
 void QgsExpressionBuilderWidget::fillFieldValues( int fieldIndex, int countLimit )
@@ -357,72 +364,71 @@ void QgsExpressionBuilderWidget::loadAllValues()
 
 QString QgsExpressionBuilderWidget::loadFunctionHelp( QgsExpressionItem* functionName )
 {
-  if ( functionName != NULL )
+  if ( functionName == NULL )
+    return "";
+
+  // set up the path to the help file
+  QString helpFilesPath = QgsApplication::pkgDataPath() + "/resources/function_help/";
+  /*
+   * determine the locale and create the file name from
+   * the context id
+   */
+  QString lang = QLocale::system().name();
+
+  QSettings settings;
+  if ( settings.value( "locale/overrideFlag", false ).toBool() )
   {
-    // set up the path to the help file
-    QString helpFilesPath = QgsApplication::pkgDataPath() + "/resources/function_help/";
-    /*
-     * determine the locale and create the file name from
-     * the context id
-     */
-    QString lang = QLocale::system().name();
-
-    QSettings settings;
-    if ( settings.value( "locale/overrideFlag", false ).toBool() )
-    {
-      QLocale l( settings.value( "locale/userLocale", "en_US" ).toString() );
-      lang = l.name();
-    }
-    /*
-     * If the language isn't set on the system, assume en_US,
-     * otherwise we get the banner at the top of the help file
-     * saying it isn't available in "your" language. Some systems
-     * may be installed without the LANG environment being set.
-     */
-    if ( lang.length() == 0 || lang == "C" )
-    {
-      lang = "en_US";
-    }
-    QString fullHelpPath = helpFilesPath + functionName->text() + "-" + lang;
-    // get the help content and title from the localized file
-    QString helpContents;
-    QFile file( fullHelpPath );
-    // check to see if the localized version exists
-    if ( !file.exists() )
-    {
-      // change the file name to the en_US version (default)
-      fullHelpPath = helpFilesPath + functionName->text() + "-en_US";
-      file.setFileName( fullHelpPath );
-
-      // Check for some sort of english locale and if not found, include
-      // translate this for us message
-      if ( !lang.contains( "en_" ) )
-      {
-        helpContents = "<i>" + tr( "This help file is not available in your language %1. If you would like to translate it, please contact the QGIS development team." ).arg( lang ) + "</i><hr />";
-      }
+    QLocale l( settings.value( "locale/userLocale", "en_US" ).toString() );
+    lang = l.name();
+  }
+  /*
+   * If the language isn't set on the system, assume en_US,
+   * otherwise we get the banner at the top of the help file
+   * saying it isn't available in "your" language. Some systems
+   * may be installed without the LANG environment being set.
+   */
+  if ( lang.length() == 0 || lang == "C" )
+  {
+    lang = "en_US";
+  }
+  QString fullHelpPath = helpFilesPath + functionName->text() + "-" + lang;
+  // get the help content and title from the localized file
+  QString helpContents;
+  QFile file( fullHelpPath );
+  // check to see if the localized version exists
+  if ( !file.exists() )
+  {
+    // change the file name to the en_US version (default)
+    fullHelpPath = helpFilesPath + functionName->text() + "-en_US";
+    file.setFileName( fullHelpPath );
 
-    }
-    if ( !file.open( QIODevice::ReadOnly | QIODevice::Text ) )
+    // Check for some sort of english locale and if not found, include
+    // translate this for us message
+    if ( !lang.contains( "en_" ) )
     {
-      helpContents = tr( "This help file does not exist for your language:<p><b>%1</b><p>If you would like to create it, contact the QGIS development team" )
-                     .arg( fullHelpPath );
+      helpContents = "<i>" + tr( "This help file is not available in your language %1. If you would like to translate it, please contact the QGIS development team." ).arg( lang ) + "</i><hr />";
     }
-    else
+
+  }
+  if ( !file.open( QIODevice::ReadOnly | QIODevice::Text ) )
+  {
+    helpContents = tr( "This help file does not exist for your language:<p><b>%1</b><p>If you would like to create it, contact the QGIS development team" )
+                   .arg( fullHelpPath );
+  }
+  else
+  {
+    QTextStream in( &file );
+    in.setCodec( "UTF-8" ); // Help files must be in Utf-8
+    while ( !in.atEnd() )
     {
-      QTextStream in( &file );
-      in.setCodec( "UTF-8" ); // Help files must be in Utf-8
-      while ( !in.atEnd() )
-      {
-        QString line = in.readLine();
-        helpContents += line;
-      }
+      QString line = in.readLine();
+      helpContents += line;
     }
-    file.close();
-
-    // Set the browser text to the help contents
-    QString myStyle = QgsApplication::reportStyleSheet();
-    helpContents = "<head><style>" + myStyle + "</style></head><body>" + helpContents + "</body>";
-    return helpContents;
   }
-  return "";
+  file.close();
+
+  // Set the browser text to the help contents
+  QString myStyle = QgsApplication::reportStyleSheet();
+  helpContents = "<head><style>" + myStyle + "</style></head><body>" + helpContents + "</body>";
+  return helpContents;
 }

src/gui/qgsexpressionbuilderwidget.h

@@ -19,6 +19,7 @@
 #include <QWidget>
 #include "ui_qgsexpressionbuilder.h"
 #include "qgsvectorlayer.h"
+#include "qgsexpressionhighlighter.h"
 
 #include "QStandardItemModel"
 #include "QStandardItem"
@@ -119,6 +120,8 @@ class GUI_EXPORT QgsExpressionBuilderWidget : public QWidget, private Ui::QgsExp
       */
     void loadFieldNames();
 
+    void loadFieldNames( QgsFieldMap fields );
+
     /** Gets the expression string that has been set in the expression area.
       * @returns The expression as a string. */
     QString getExpressionString();
@@ -137,6 +140,7 @@ class GUI_EXPORT QgsExpressionBuilderWidget : public QWidget, private Ui::QgsExp
                        QString helpText = "",
                        QgsExpressionItem::ItemType type = QgsExpressionItem::ExpressionNode );
 
+
   public slots:
     void on_expressionTree_clicked( const QModelIndex &index );
     void on_expressionTree_doubleClicked( const QModelIndex &index );
@@ -166,6 +170,7 @@ class GUI_EXPORT QgsExpressionBuilderWidget : public QWidget, private Ui::QgsExp
     QgsExpressionItemSearchProxy *mProxyModel;
     QMap<QString, QgsExpressionItem*> mExpressionGroups;
     QgsFeature mFeature;
+    QgsExpressionHighlighter* highlighter;
 };
 
 #endif // QGSEXPRESSIONBUILDER_H

src/gui/qgsexpressionhighlighter.cpp

@@ -0,0 +1,60 @@
+/***************************************************************************
+    qgsexpressionhighlighter.cpp - A syntax highlighter for a qgsexpression
+     --------------------------------------
+    Date                 :  28-Dec-2011
+    Copyright            : (C) 2011 by Nathan Woodrow
+    Email                : woodrow.nathan at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsexpressionhighlighter.h"
+
+QgsExpressionHighlighter::QgsExpressionHighlighter( QTextDocument *parent)
+    : QSyntaxHighlighter( parent )
+{
+  HighlightingRule rule;
+
+  quotationFormat.setForeground( Qt::darkGreen );
+  rule.pattern = QRegExp( "\'.*\'" );
+  rule.format = quotationFormat;
+  highlightingRules.append( rule );
+
+  columnNameFormat.setForeground( Qt::darkRed );
+  rule.pattern = QRegExp( "\".*\"" );
+  rule.format = columnNameFormat;
+  highlightingRules.append( rule );
+}
+
+void QgsExpressionHighlighter::addFields(QStringList fieldList)
+{
+    columnNameFormat.setForeground( Qt::darkRed );
+    HighlightingRule rule;
+    foreach (const QString field, fieldList)
+    {
+        rule.pattern = QRegExp("\\b" + field + "\\b");
+        rule.format = columnNameFormat;
+        highlightingRules.append( rule );
+    }
+}
+
+void QgsExpressionHighlighter::highlightBlock( const QString &text )
+{
+  foreach( const HighlightingRule &rule, highlightingRules )
+  {
+    QRegExp expression( rule.pattern );
+    int index = expression.indexIn( text );
+    while ( index >= 0 )
+    {
+      int length = expression.matchedLength();
+      setFormat( index, length, rule.format );
+      index = expression.indexIn( text, index + length );
+    }
+  }
+}
+

src/gui/qgsexpressionhighlighter.h

@@ -0,0 +1,53 @@
+/***************************************************************************
+    qgsexpressionhighlighter.h - A syntax highlighter for a qgsexpression
+     --------------------------------------
+    Date                 :  28-Dec-2011
+    Copyright            : (C) 2011 by Nathan Woodrow
+    Email                : woodrow.nathan at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSEXPRESSIONHIGHLIGHTER_H
+#define QGSEXPRESSIONHIGHLIGHTER_H
+
+#include "qgsfield.h"
+#include <QSyntaxHighlighter>
+
+#include <QHash>
+#include <QTextCharFormat>
+#include <QStringList>
+
+class QTextDocument;
+
+class QgsExpressionHighlighter : QSyntaxHighlighter
+{
+    Q_OBJECT
+
+  public:
+    QgsExpressionHighlighter( QTextDocument *parent = 0 );
+    void addFields( QStringList fieldList );
+
+  protected:
+    void highlightBlock( const QString &text );
+
+  private:
+    struct HighlightingRule
+    {
+      QRegExp pattern;
+      QTextCharFormat format;
+    };
+    QVector<HighlightingRule> highlightingRules;
+
+    QTextCharFormat columnNameFormat;
+    QTextCharFormat keywordFormat;
+    QTextCharFormat quotationFormat;
+    QTextCharFormat functionFormat;
+};
+
+#endif // QGSEXPRESSIONHIGHLIGHTER_H