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Trouble with semantic highlighting [message #763371]

Fri, 09 December 2011 16:48

Romain Aïssat

Messages: 16
Registered: June 2011

Junior Member

Hi all,

I've got some troubles with a particular case of semantic highlighting. Here is the grammar :

grammar org.xtext.Tsh with org.eclipse.xtext.common.Terminals

generate tsh "http://www.xtext.org/Tsh"

Model:
	(definitions += Definition)*
	(expressions += ExpressionRule ';')* ;
	
Definition :
	'def' alias = Alias;
	
Alias :
	name = ID;	
	
ExpressionRule returns Expression :
	'common' 'Prefix' TerminalExpression 
	( {TypeA.left = current} 'suffixA' right = TerminalExpression
	| {TypeB.left = current} 'suffixB' right = TerminalExpression
	);
	
Constant :
	value = INT;
	
TerminalExpression returns Expression :
	Constant | '(' ExpressionRule ')' | Reference;
	
Reference :
	Reference = [Alias];

In my uiModule, i binded ISemanticHighlightingCalculator and IHighlightingConfiguration to my implementations of these interfaces. Here are the two implementations :

package org.xtext.ui;

import org.eclipse.xtext.nodemodel.INode;
import org.eclipse.xtext.nodemodel.impl.CompositeNodeWithSemanticElement;
import org.eclipse.xtext.resource.XtextResource;
import org.eclipse.xtext.ui.editor.syntaxcoloring.IHighlightedPositionAcceptor;
import org.eclipse.xtext.ui.editor.syntaxcoloring.ISemanticHighlightingCalculator;
import org.xtext.tsh.Constant;
import org.xtext.tsh.Reference;
import org.xtext.tsh.TypeA;
import org.xtext.tsh.TypeB;

public class TshSemanticHighlightingCalculator implements ISemanticHighlightingCalculator {

	@Override
	public void provideHighlightingFor(XtextResource resource, IHighlightedPositionAcceptor acceptor) {
		if (resource == null || resource.getParseResult() == null)
			return;
		    
		INode root = resource.getParseResult().getRootNode();
		for (INode node : root.getAsTreeIterable()) {
			if(node instanceof CompositeNodeWithSemanticElement){
				CompositeNodeWithSemanticElement compositeNode = (CompositeNodeWithSemanticElement) node;
				if (node.getSemanticElement() instanceof Constant || node.getSemanticElement() instanceof Reference) {
					acceptor.addPosition(node.getOffset(), node.getLength(), TshHighlightingConfiguration.CONSTANT_ID);
				}
				if(compositeNode.getSemanticElement() instanceof TypeA){
					for(INode subNode : compositeNode.getChildren()){
						System.out.println(subNode.getText());
					}
					System.out.println();
					acceptor.addPosition(node.getOffset(), node.getLength(), TshHighlightingConfiguration.TYPE_A_ID);
				}
				if(compositeNode.getSemanticElement() instanceof TypeB){
					for(INode subNode : compositeNode.getChildren()){
						System.out.println(subNode.getText());
					}
					System.out.println();
					acceptor.addPosition(node.getOffset(), node.getLength(), TshHighlightingConfiguration.TYPE_B_ID);
				}
			}
		}
	}

}

and

package org.xtext.ui;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.xtext.ui.editor.syntaxcoloring.DefaultHighlightingConfiguration;
import org.eclipse.xtext.ui.editor.syntaxcoloring.IHighlightingConfigurationAcceptor;
import org.eclipse.xtext.ui.editor.utils.TextStyle;

public class TshHighlightingConfiguration extends DefaultHighlightingConfiguration {
	
	public static final String 
		CONSTANT_ID = "constant",
		TYPE_A_ID = "typeA",
		TYPE_B_ID = "typeB";
	
	public void configure(IHighlightingConfigurationAcceptor acceptor){
		super.configure(acceptor);
		acceptor.acceptDefaultHighlighting(CONSTANT_ID, "Constants", constantTextStyle());
		acceptor.acceptDefaultHighlighting(TYPE_A_ID, "Type A", aTextStyle());
		acceptor.acceptDefaultHighlighting(TYPE_B_ID, "Type B", bTextStyle());
	}
	
	public TextStyle constantTextStyle(){
		TextStyle style = new TextStyle();
		style.setColor(new RGB(1,1,254));
		style.setStyle(SWT.BOLD);
		return style;
	}
	
	public TextStyle aTextStyle(){
		TextStyle style = new TextStyle();
		style.setColor(new RGB(254,1,1));
		style.setStyle(SWT.BOLD);
		return style;
	}
	
	public TextStyle bTextStyle(){
		TextStyle style = new TextStyle();
		style.setColor(new RGB(1,254,1));
		style.setStyle(SWT.BOLD);
		return style;
	}

}

Here is the model :

common Prefix 1 suffixA 1;
common Prefix 2 suffixB 2;

The problem is : if I modify the keyword "Prefix" in one of the two expressions, like writing for example "Preofix", then it will raise of course a syntax error and the keyword Prefix will no more be highlighted as intended but as Reference. This is ok. But when i fix "Preofix" to "Prefix", "Prefix" is now highlighted as a default keyword (RGB.color = (127,0,85), style = SWT.BOLD == default eclipse keyword style) when it should be highlighted as TypeA or TypeB (depending on the line of the model I modified).

I've tried different ways to fix this, but in vain.

If somebody knows a way to fix it... Thanks in advance!

Romain

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