java-1.7-preprocessor.sablecc

/* This file is part of the Java 1.5 grammar for SableCC.
 *
 * Copyright 2006 Etienne M. Gagnon <egagnon@j-meg.com>
 *
 * 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.
 */

// Note: this hasn't yet been verified to exactly match the
// specification.

Package org.sablecc.grammars.java_1_5.unicodepreprocessor;

Helpers
    any_unicode_character = [0..0xffff];
    unicode_marker = 'u'+;
    hex_digit = ['0'..'9'] | ['a'..'f'] | ['A'..'F'];

States
    normal,
    sub;

Tokens
/*************************************************************************************
 * The precedence of longer and earlier definitions is important! The sequence '\\u' *
 * will generate two tokens: even_backslash('\\') and raw_input_character('u').      *
 *************************************************************************************/

    even_backslash = '\\';
        /* The preprocessor should return two unicode characters: '\' '\' */

    unicode_escape = '\' unicode_marker hex_digit hex_digit hex_digit hex_digit;
        /* The preprocessor should return a single unicode character */
    
    erroneous_escape = '\' unicode_marker hex_digit? hex_digit? hex_digit?;
        /* The preprocessor should issue an error */

{normal->sub, sub}
    sub = 0x001a;
        /* The preprocessor should discard a SUB ASCII character if it is the last  */
        /* character on the input reader.                                           */
        /* This requires the use of a customized lexer that derives from Lexer and  */
        /* that puts the TSub token in a buffer until the next token is read.       */
        /* If the next token is EOF, EOF is returned, and the state should be reset */
        /* to normal. Else, the text of next token is pushed back on the input      */
        /* reader, the buffered TSub token is returned, and the state is reset to   */
        /* normal.                                                                  */

    raw_input_character = any_unicode_character;
        /* The preprocessor should return a single unicode character */