/**
 * Copyright 2017 Matt Acosta
 *
 * 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.
 */
import { ISyntaxNode, ISyntaxNodeOrList } from './ISyntaxNode';
import { SyntaxNodeBase } from './SyntaxNodeBase';
import { SyntaxTransform } from './SyntaxTransform.Generated';
import { SyntaxVisitor } from './SyntaxVisitor.Generated';
/**
 * A non-terminal node in a syntax tree.
 */
export declare abstract class SyntaxNode extends SyntaxNodeBase implements ISyntaxNode {
    /**
     * @inheritDoc
     */
    abstract accept(visitor: SyntaxVisitor): void;
    /**
     * @inheritDoc
     */
    abstract acceptResult<T>(visitor: SyntaxTransform<T>): T;
    /**
     * Creates a syntax node for a child at the given index.
     *
     * @return {T|null}
     *   A child syntax node, or `null` if the child was undefined or not a node.
     *
     * @see createFirstChildNode()
     */
    protected createChildNode<T extends ISyntaxNodeOrList>(index: number): T | null;
    /**
     * Creates the first child syntax node of the current node.
     *
     * This is a slight optimization of `createChildNode()`.
     *
     * @return {T|null}
     *   A child syntax node, or `null` if the first child was undefined or not a
     *   node.
     */
    protected createFirstChildNode<T extends ISyntaxNodeOrList>(): T | null;
}