[#1731] Updating the Eclipse Support webpage.

- Add Mark Occurrences and Find References section.
- Improve Folding section to break the long lines of the embedded
code snippets properly.

Signed-off-by: Tamas Miklossy <miklossy@itemis.de>

xtext-website/documentation/310_eclipse_support.md

@@ -502,42 +502,51 @@ In order to make `events`, `resetEvents` and `commands` foldable too, a custom i
 ```java
 public class StatemachineFoldingRegionProvider extends DefaultFoldingRegionProvider {
 
-	@Override
-	protected void computeObjectFolding(EObject o, IFoldingRegionAcceptor<ITextRegion> foldingRegionAcceptor) {
-		if (o instanceof Statemachine) {
-			XtextResource res = (XtextResource) o.eResource();
-			computeEventsFolding(res, foldingRegionAcceptor);
-			computeResetEventsFolding(res, foldingRegionAcceptor);
-			computeCommandsFolding(res, foldingRegionAcceptor);
-		} else {
-			super.computeObjectFolding(o, foldingRegionAcceptor);
-		}
-	}
+  @Override
+  protected void computeObjectFolding(
+    EObject o,
+    IFoldingRegionAcceptor<ITextRegion> foldingRegionAcceptor) {
+
+    if (o instanceof Statemachine) {
+      XtextResource res = (XtextResource) o.eResource();
+      computeEventsFolding(res, foldingRegionAcceptor);
+      computeResetEventsFolding(res, foldingRegionAcceptor);
+      computeCommandsFolding(res, foldingRegionAcceptor);
+    } else {
+      super.computeObjectFolding(o, foldingRegionAcceptor);
+    }
+  }
 
-	private void computeEventsFolding(XtextResource res, IFoldingRegionAcceptor<ITextRegion> foldingRegionAcceptor) {
-		...
-	}
+  private void computeEventsFolding(
+    XtextResource res,
+    IFoldingRegionAcceptor<ITextRegion> foldingRegionAcceptor) {
+    ...
+  }
 
-	private void computeResetEventsFolding(XtextResource res, IFoldingRegionAcceptor<ITextRegion> foldingRegionAcceptor) {
-		...
-	}
+  private void computeResetEventsFolding(
+    XtextResource res,
+    IFoldingRegionAcceptor<ITextRegion> foldingRegionAcceptor) {
+    ...
+  }
 
-	private void computeCommandsFolding(XtextResource res, IFoldingRegionAcceptor<ITextRegion> foldingRegionAcceptor) {
-		...
-	}
-	...
+  private void computeCommandsFolding(
+    XtextResource res,
+    IFoldingRegionAcceptor<ITextRegion> foldingRegionAcceptor) {
+    ...
+  }
+  ...
 }
 ```
 
 Additionally, the [StatemachineFoldingRegionProvider]({{site.src.xtext_eclipse}}/org.eclipse.xtext.xtext.ui.examples/projects/fowlerdsl/org.eclipse.xtext.example.fowlerdsl.ui/src/org/eclipse/xtext/example/fowlerdsl/ui/folding/StatemachineFoldingRegionProvider.java) class has to be bound in the [StatemachineUiModule]({{site.src.xtext_eclipse}}/org.eclipse.xtext.xtext.ui.examples/projects/fowlerdsl/org.eclipse.xtext.example.fowlerdsl.ui/src/org/eclipse/xtext/example/fowlerdsl/ui/StatemachineUiModule.java):
 ```java
 public class StatemachineUiModule extends AbstractStatemachineUiModule {
 
-	...
+  ...
 
-	public Class<? extends IFoldingRegionProvider> bindIFoldingRegionProvider() {
-		return StatemachineFoldingRegionProvider.class;
-	}
+  public Class<? extends IFoldingRegionProvider> bindIFoldingRegionProvider() {
+    return StatemachineFoldingRegionProvider.class;
+  }
 }
 ```
 
@@ -604,6 +613,36 @@ public class MyDslUiModule extends AbstractMyDslUiModule {
 }
 ```
 
+## Mark Occurrences {#maroccurrences}
+Xtext-based editors are able to highlight all occurrences of a certain element in the opened DSL file. Once the user selects an element while the `Toggle Mark Occurrences` button is enabled, all occurrences are highlighted with corresponding markers on the right side of the editor.
+
+![](images/mark_occurrences.png)
+
+Customization can happen by either extending the [DefaultOccurrenceComputer]({{site.src.xtext_eclipse}}/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/editor/occurrences/DefaultOccurrenceComputer.java) class or even providing a complete implementation of the [IOccurrenceComputer]({{site.src.xtext_eclipse}}/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/editor/occurrences/IOccurrenceComputer.java) interface.
+
+```java
+public class MyDslOccurrenceComputer extends DefaultOccurrenceComputer {
+	...
+}
+```
+
+```java
+public class MyDslUiModule extends AbstractMyDslUiModule {
+
+	public Class<? extends IOccurrenceComputer> bindIOccurrenceComputer() {
+		return MyDslOccurrenceComputer.class;
+	}
+
+}
+```
+
+## Find References {#findreferences}
+Xtext-based editors are able to locate all references in the entire workspace where a certain element is referred to. Invoking the `Find References` context menu or using the keyboard shortcut `Ctlr+Shift+G` (`Cmd+Shift+G` on Mac) on the selected element lists all the references in the `Search` view.
+
+![](images/find_references.gif)
+
+The [org.eclipse.xtext.findReferences.IReferenceFinder]({{site.src.xtext_core}}/org.eclipse.xtext/src/org/eclipse/xtext/findReferences/IReferenceFinder.java) and the [org.eclipse.xtext.ui.editor.findrefs.IReferenceFinder]({{site.src.xtext_eclipse}}/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/editor/findrefs/IReferenceFinder.java) interfaces are responsible for this functionality. These interfaces are implemented by the [ReferenceFinder]({{site.src.xtext_core}}/org.eclipse.xtext/src/org/eclipse/xtext/findReferences/ReferenceFinder.java) and the [DelegatingReferenceFinder]({{site.src.xtext_eclipse}}/org.eclipse.xtext.ui/src/org/eclipse/xtext/ui/editor/findrefs/DelegatingReferenceFinder.java) classes. As almost everything in the Xtext framework, these components can also be customized if the default implementations do not satisfy your needs.
+
 ## Syntax Coloring {#highlighting}
 
 Besides the already mentioned advanced features like [content assist](#content-assist) and [code formatting](303_runtime_concepts.html#formatting) the powerful editor for your DSL is capable to mark up your model-code to improve the overall readability. It is possible to use different colors and fonts according to the meaning of the different parts of your input file. One may want to use some unintrusive colors for large blocks of comments while identifiers, keywords and strings should be colored differently to make it easier to distinguish between them. This kind of text decorating markup does not influence the semantics of the various sections but helps to understand the meaning and to find errors in the source code.