/*
 * Copyright 2016 The Bazel Authors. All rights reserved.
 *
 * 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.google.idea.blaze.base.lang.buildfile.lexer;

/**
 * A Token represents an actual lexeme; that is, a lexical unit, its location in
 * the input text, its lexical kind, and any associated value.
 */
public class Token {

  public final TokenKind kind;
  public final int left;
  public final int right;
  public final Object value;

  public Token(TokenKind kind, int left, int right) {
    this(kind, left, right, null);
  }

  public Token(TokenKind kind, int left, int right, Object value) {
    this.kind = kind;
    this.left = left;
    this.right = right;
    this.value = value;
  }

  /**
   * Constructs an easy-to-read string representation of token, suitable for use
   * in user error messages.
   */
  @Override
  public String toString() {
    if (kind == TokenKind.STRING) {
      return "\"" + value + "\"";
    }
    return value == null ? kind.toString() : value.toString();
  }

}