Bug 123040 [Commands] request: display help topic
I'm going to attach a patch to "command-ify" the opening of help topics. The command takes a parameter which is the href of a help topic. The default handler uses IWorkbenchHelpSystem.displayHelpResource(String) with the href parameter. If no parameter was given, the default handler calls IWorkbenchHelpSystem.displayHelp() instead to simply open the help system. Note that this looks like it should be opened against User Assistance, but the plugins that should be patched (I think) are org.eclipse.ui and org.eclipse.ui.workbench, so I opened against UI.
bundles/org.eclipse.core.commands/src/org/eclipse/core/commands/ParameterizedCommand.java
}
		if (buffer == null)
			return rawText;
		return buffer.toString();
	}
	/**
	 * Generates every possible combination of parameter values for the given
	 * parameters. Parameters values that cannot be initialized are just
	 * ignored. Optional parameters are considered.
	 * 
	 * @param startIndex
	 *            The index in the <code>parameters</code> that we should
	 *            process. This must be a valid index.
	 * @param parameters
	 *            The parameters in to process; must not be <code>null</code>.
	 * @return A collection (<code>Collection</code>) of combinations (<code>List</code>
	 *         of <code>Parameterization</code>).
	 * 
	 */
	private static final Collection expandParameters(final int startIndex,
			final IParameter[] parameters) {
		final boolean noMoreParameters = (startIndex + 1 >= parameters.length);
		final IParameter parameter = parameters[startIndex];
		IParameterValues values = null;
		try {
			values = parameter.getValues();
		} catch (final ParameterValuesException e) {
			if (noMoreParameters) {
				return Collections.EMPTY_LIST;
			}