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// Copyright 2014 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.devtools.build.lib.syntax;
import javax.annotation.Nullable;
/**
* A Token represents an actual lexeme; that is, a lexical unit, its location in
* the input text, its lexical kind (TokenKind) and any associated value.
*/
class Token {
TokenKind kind;
int left;
int right;
/**
* value is an Integer if the kind is INT.
* It is a String if the kind is STRING, IDENTIFIER, or COMMENT.
* It is null otherwise.
*/
@Nullable Object value;
Token(TokenKind kind, int left, int right) {
this(kind, left, right, null);
}
Token(TokenKind kind, int left, int right, Object value) {
this.kind = kind;
this.left = left;
this.right = right;
this.value = value;
}
Token copy() {
return new Token(kind, left, right, value);
}
/**
* Constructs an easy-to-read string representation of token, suitable for use
* in user error messages.
*/
@Override
public String toString() {
// TODO(bazel-team): do proper escaping of string literals
return kind == TokenKind.STRING ? ("\"" + value + "\"")
: value == null ? kind.getPrettyName()
: value.toString();
}
}
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