/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * 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 parser

import lexer.Token

/**
 * Returns the next token in the iteration, without advancing the iteration.
 */
fun peekToken(iter: ListIterator<Token>): Token? {
    if (iter.hasNext()) {
        val token = iter.next()
        iter.previous()
        return token
    } else {
        return null
    }
}

fun peekPreviousToken(iter: ListIterator<Token>): Token? {
    if (iter.hasPrevious()) {
        val token = iter.previous()
        iter.next()
        return token
    } else {
        return null
    }
}