com.vaadin.sass.internal.tree.FunctionNode Maven / Gradle / Ivy

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/*
 * Copyright 2000-2014 Vaadin Ltd.
 * 
 * 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 com.vaadin.sass.internal.tree;

import java.util.Collections;

import com.vaadin.sass.internal.ScssStylesheet;
import com.vaadin.sass.internal.parser.LexicalUnitImpl;
import com.vaadin.sass.internal.parser.ParseException;
import com.vaadin.sass.internal.parser.SassListItem;

/**
 * Transient class representing a function call to a custom (user-defined)
 * function. This class is used to evaluate the function call and is discarded
 * after use. A FunctionNode does not have a parent in the stylesheet node tree.
 */
public class FunctionNode extends NodeWithVariableArguments {
    private static final long serialVersionUID = -5383104165955523923L;

    private FunctionDefNode def;
    private SassListItem value = null;

    public FunctionNode(FunctionDefNode def, LexicalUnitImpl invocation) {
        super(invocation.getFunctionName(), invocation.getParameterList());

        this.def = def;
        expandVariableArguments();
    }

    @Override
    public String toString() {
        return "Function Node: {name: " + getName() + ", args: " + getArglist()
                + "}";
    }

    public SassListItem evaluate() {
        traverse();
        // already evaluated
        if (value == null) {
            throw new ParseException("Function " + getName()
                    + " did not return a value", this);
        }
        return value;
    }

    @Override
    public void doTraverse() {
        // TODO should this be called?
        // replaceVariables(ScssStylesheet.getVariables());

        // copying is necessary as traversal modifies the parent of the
        // node
        FunctionDefNode defCopy = def.copy();
        defCopy.replacePossibleArguments(getArglist());
        for (VariableNode param : defCopy.getArglist()) {
            ScssStylesheet.addVariable(param);
        }

        // only contains variable nodes, return nodes and control
        // structures
        while (defCopy.getChildren().size() > 0) {
            defCopy.getChildren().get(0).traverse();
            if (defCopy.getChildren().get(0) instanceof ReturnNode) {
                ReturnNode returnNode = ((ReturnNode) defCopy.getChildren()
                        .get(0));
                value = returnNode.evaluate(Collections
                        . emptyList());
                break;
            }
        }
    }

}