Add CASE and CASE ELSE to expression builder groups

NathanW2 · NathanW2 · commit 0cd93a23780a · 2012-07-22T11:53:25.000+10:00
- Use readAll() for function help to preserve html
diff --git a/resources/function_help/CASE ELSE-en_US b/resources/function_help/CASE ELSE-en_US
@@ -0,0 +1,32 @@
+<h3>CASE statement</h3>
+A conditional statement that can be used to evaluate exissions and 
+return a result.
+
+<h4>Syntax</h4>
+<pre>
+     CASE
+        WHEN <i>expression</i> THEN <i>result</i>
+        [ ...n ]
+        ELSE <i>result</i>
+     END
+</pre>
+[ ] marks optional statements
+
+
+<h4>Arguments</h4>
+<!-- List args for functions here-->
+<i>  WHEN expression</i> - The expression to evaluate. <br>
+<i>  THEN result</i> - If <i>expression</i> evaluates True then <i>result</i> is returned. <br>
+<i>  ELSE result</i> - If <i>expression</i> evaluates False then <i>result</i> is returned. <br>
+ 
+
+
+<h4>Example</h4>
+<!-- Show example of function.-->
+<pre>
+    CASE
+        WHEN <i>"column" IS NULL</i> THEN <i>'None'</i>
+        ELSE <i>"column"</i>
+    END
+</pre>
+
diff --git a/resources/function_help/CASE-en_US b/resources/function_help/CASE-en_US
@@ -0,0 +1,31 @@
+<h3>CASE statement</h3>
+A conditional statement that can be used to evaluate exissions and 
+return a result.
+
+<h4>Syntax</h4>
+<pre>
+     CASE
+        WHEN <i>expression</i> THEN <i>result</i>
+        [ ...n ]
+        [ ELSE <i>result</i> ]
+     END
+</pre>
+[ ] marks optional statements
+
+
+<h4>Arguments</h4>
+<!-- List args for functions here-->
+<i>  WHEN expression</i> - The expression to evaluate. <br>
+<i>  THEN result</i> - If <i>expression</i> evaluates True then <i>result</i> is returned. <br>
+<i>  ELSE result</i> - If <i>expression</i> evaluates False then <i>result</i> is returned. <br>
+ 
+
+
+<h4>Example</h4>
+<!-- Show example of function.-->
+<pre>
+    CASE
+        WHEN <i>"column" IS NULL</i> THEN <i>'None'</i>
+    END
+</pre>
+
diff --git a/src/gui/qgsexpressionbuilderwidget.cpp b/src/gui/qgsexpressionbuilderwidget.cpp
@@ -79,6 +79,10 @@ QgsExpressionBuilderWidget::QgsExpressionBuilderWidget( QWidget *parent )
   registerItem( tr( "Operators" ), "AND", " AND " );
   registerItem( tr( "Operators" ), "NOT", " NOT " );
 
+  QString casestring = "CASE WHEN condition THEN result END";
+  QString caseelsestring = "CASE WHEN condition THEN result ELSE result END";
+  registerItem( tr( "Conditionals" ), "CASE", casestring );
+  registerItem( tr( "Conditionals" ), "CASE ELSE", caseelsestring );
 
   // Load the functions from the QgsExpression class
   int count = QgsExpression::functionCount();
@@ -380,9 +384,9 @@ void QgsExpressionBuilderWidget::setExpressionState( bool state )
   mExpressionValid = state;
 }
 
-QString QgsExpressionBuilderWidget::loadFunctionHelp( QgsExpressionItem* functionName )
+QString QgsExpressionBuilderWidget::loadFunctionHelp( QgsExpressionItem* expressionItem )
 {
-  if ( functionName == NULL )
+  if ( expressionItem == NULL )
     return "";
 
   // set up the path to the help file
@@ -410,9 +414,9 @@ QString QgsExpressionBuilderWidget::loadFunctionHelp( QgsExpressionItem* functio
     lang = "en_US";
   }
 
-  QString name = functionName->text();
+  QString name = expressionItem->text();
 
-  if ( functionName->getItemType() == QgsExpressionItem::Field )
+  if ( expressionItem->getItemType() == QgsExpressionItem::Field )
     name = "Field";
 
   QString fullHelpPath = helpFilesPath + name + "-" + lang;
@@ -434,7 +438,7 @@ QString QgsExpressionBuilderWidget::loadFunctionHelp( QgsExpressionItem* functio
       missingError += tr( "It was neither available in your language (%1) nor English." ).arg( lang );
 
       // try en_US next
-      fullHelpPath = helpFilesPath + functionName->text() + "-en_US";
+      fullHelpPath = helpFilesPath + name + "-en_US";
       file.setFileName( fullHelpPath );
     }
   }
@@ -449,11 +453,7 @@ QString QgsExpressionBuilderWidget::loadFunctionHelp( QgsExpressionItem* functio
   {
     QTextStream in( &file );
     in.setCodec( "UTF-8" ); // Help files must be in Utf-8
-    while ( !in.atEnd() )
-    {
-      QString line = in.readLine();
-      helpContents += line;
-    }
+    helpContents = in.readAll();
   }
 
   file.close();
