com.inet.sass.visitor.LoopNodeHandler Maven / Gradle / Ivy

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/*
 * Copyright 2023 i-net software
 * 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.inet.sass.visitor;

import java.util.Collection;
import java.util.List;

import com.inet.sass.ScssContext;
import com.inet.sass.parser.Variable;
import com.inet.sass.tree.Node;
import com.inet.sass.tree.controldirective.TemporaryNode;

/**
 * Base class for handlers of all kinds of looping nodes (@for, @while, @each).
 */
public abstract class LoopNodeHandler {

    /**
     * Replace a loop node (e.g. ForNode) with the expanded set of nodes.
     * 
     * @param context
     *            current compilation context
     * @param loopNode
     *            node to replace
     * @param loopVariables
     *            iterable of the loop variables instances for each iteration -
     *            typically a collection for a fixed iteration count loop
     */
    protected static Collection replaceLoopNode( ScssContext context, Node loopNode, Iterable> loopVariables ) {
        // the type of this node does not matter much as long as it can have
        // children that can be traversed
        TemporaryNode tempParent = new TemporaryNode( loopNode.getParentNode() );
        List children = loopNode.getChildren();
        for( final List vars : loopVariables ) {
            iteration( context, children, tempParent, vars );
        }
        // the newly created nodes have already been traversed
        return tempParent.getChildren();
    }

    static void iteration( ScssContext context, List loopChildren, TemporaryNode newParent, List loopVariables ) {
        context.openVariableScope();
        try {
            for( Variable loopVar : loopVariables ) {
                context.addVariable( loopVar );
            }
            for( final Node child : loopChildren ) {
                Node copy = child.copy();
                newParent.appendAndTraverse( context, copy );
            }
        } finally {
            context.closeVariableScope();
        }
    }
}