PDT/Dev2Dev/Semantic

Semantic Highlighting

Overview

Following the improvements done by the Web tools project (232752) on semantic highlighting, the PHP Source Editor can now set semantic rules for better coloring techniques that will improve its performance and functionality. For example, currently, all variables are highlighted in the same color. Although members / static / constants variables should be colored in separate colors just like the Java editor does.

The following screenshot demonstrate the power of the semantic coloring:

The latest version of the patch is available at 271430.

API

The PHP semantic highlighting API is used to define semantic rules for PHP coloring. It's also useful for plugin developpers who would like to extends PHP highlighting with specific semantic rules.

The first step is to use the org.eclipse.wst.sse.ui.semanticHighlighting extension point with the org.eclipse.php.core.phpsource target. By using the PHP source target, PHP UI plugin is automatically registering this contributor as a semantic highlighter.

<extension point="org.eclipse.wst.sse.ui.semanticHighlighting">
  <highlighting
    class="org.eclipse.php.internal.ui.editor.highlighting.ParameterVariableHighlighting"
    target="org.eclipse.php.core.phpsource">
  </highlighting>
</extension>

The given class must extend org.eclipse.php.internal.ui.editor.highlighter.AbstractSemanticHighlighting.

public class ParameterVariableHighlighting extends AbstractSemanticHighlighting {
 
  @Override
  public AbstractSemanticApply getSemanticApply() {
    return new ParameterVariableApply();
  }
 
  @Override
  public void initDefaultPreferences() {
    getStyle().setUnderlineByDefault(true)
              .setDefaultTextColor(new RGB(102, 0, 0));
  }
 
  public String getDisplayName() {
    return "Local variables";
  }
}

Since some rules might be conflicting between each other, you can define the priority rules. For instance, the InternalClassHighlighting rule has to override the ClassHighlighting rule. You can use the @HighlightingPriority annotation to define the application order of the semantic rules.

@HighlightingPriority(Priority.HIGH)
public class InternalClassHighlighting extends AbstractSemanticHighlighting {

The AbstractSemanticApply is simple visitor of PHP AST model. Once a node to be colored is matched, it can be added to the semantic coloring using the highlight method.

protected class InterfaceApply extends AbstractSemanticApply {
 
  @Override
  public boolean visit(ClassDeclaration classDecl) {
    for (Identifier type: classDecl.interfaces()) {
      highlight(type);
    }
    return true;
  }
 
  @Override
  public boolean visit(InterfaceDeclaration interfaceDecl) {
    highlight(interfaceDecl.getName());
    for (Identifier type: classDecl.interfaces()) {
      highlight(type);
    }
    return true;
  }
}

The following table describes the semantic rules that have been implemented so far and their default style.

Rule	Default Style	Enabled by default
Constants	Bold	True
Field		False
Function		False
Internal Function	Blue	True
Global Variable	Blue	True
Local variable		False
Method		False
Static Field	Italic	True
Static Method		False
Classes	Blue	True
Internal Classes	Blue	True
Internal Interfaces	Blue	True
Interfaces		False
Parameter Variables	Underline	True
Super Globales	Light blue	True

UI

The rules are automatically added to the Syntax Coloring preference page:

Performances

Work in progress...