org.sweble.wikitext.engine.ext.ParserFunctionIf Maven / Gradle / Ivy

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A minimal engine using the Sweble Wikitext Parser to process articles in the context of a MediaWiki-like configuration.

There is a newer version: 3.1.9

/**
 * Copyright 2011 The Open Source Research Group,
 *                University of Erlangen-Nürnberg
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.sweble.wikitext.engine.ext;

import java.util.LinkedList;

import org.sweble.wikitext.engine.ExpansionFrame;
import org.sweble.wikitext.engine.ParserFunctionBase;
import org.sweble.wikitext.lazy.preprocessor.Template;
import org.sweble.wikitext.lazy.utils.StringConversionException;
import org.sweble.wikitext.lazy.utils.StringConverter;
import org.sweble.wikitext.lazy.utils.TextUtils;

import de.fau.cs.osr.ptk.common.ast.AstNode;
import de.fau.cs.osr.ptk.common.ast.NodeList;

public class ParserFunctionIf
        extends
            ParserFunctionBase
{
	private static final long serialVersionUID = 1L;
	
	public ParserFunctionIf()
	{
		super("#if");
	}
	
	@Override
	public AstNode invoke(Template template, ExpansionFrame preprocessorFrame, LinkedList args)
	{
		if (args.size() < 2)
			return new NodeList();
		
		AstNode test = preprocessorFrame.expand(args.get(0));
		
		String testStr = null;
		try
		{
			testStr = StringConverter.convert(test).trim();
		}
		catch (StringConversionException e1)
		{
			// FIXME: Do recursive equality check
		}
		
		boolean eval = false;
		if (testStr != null)
			eval = !testStr.isEmpty();
		
		AstNode result;
		if (eval)
		{
			result = args.get(1);
		}
		else
		{
			result = null;
			if (args.size() >= 3)
				result = args.get(2);
		}
		
		if (result != null)
			result = preprocessorFrame.expand(result);
		
		if (result == null)
			result = new NodeList();
		
		if (result.isNodeType(AstNode.NT_NODE_LIST))
			return TextUtils.trim((NodeList) result);
		
		return result;
	}
}