Line data    Source code

       1              : // Copyright 2026 The Authors. See the AUTHORS file for details.
       2              : //
       3              : // Licensed under the Apache License, Version 2.0 (the "License");
       4              : // you may not use this file except in compliance with the License.
       5              : // You may obtain a copy of the License at
       6              : //
       7              : //      https://www.apache.org/licenses/LICENSE-2.0
       8              : //
       9              : // Unless required by applicable law or agreed to in writing, software
      10              : // distributed under the License is distributed on an "AS IS" BASIS,
      11              : // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      12              : // See the License for the specific language governing permissions and
      13              : // limitations under the License.
      14              : 
      15              : /// ABNF core rules as defined in RFC 5234, Appendix B.1.
      16              : library;
      17              : 
      18              : import 'grammar.dart';
      19              : 
      20           12 : final alphaLower = rule('ALPHA-LOWER', valueRange(0x61, 0x7A));
      21              : 
      22            8 : final alphaUpper = rule('ALPHA-UPPER', valueRange(0x41, 0x5A));
      23              : 
      24           14 : final alpha = rule('ALPHA', alternatives([alphaLower, alphaUpper]));
      25              : 
      26            5 : final bit = rule('BIT', alternativeLiterals(['0', '1']));
      27              : 
      28            4 : final char = rule('CHAR', valueRange(0x01, 0xFF));
      29              : 
      30            4 : final cr = rule('CR', character(0x0D));
      31              : 
      32            7 : final crlf = rule('CRLF', Concatenation([cr, lf]));
      33              : 
      34              : /// Controls characters (range %x00-1F / %x7F).
      35            3 : final ctl = rule(
      36              :   'CTL',
      37            4 :   alternatives([valueRange(0x00, 0x1F), character(0x7f)]),
      38              : );
      39              : 
      40            8 : final digit = rule('DIGIT', valueRange(0x30, 0x39));
      41              : 
      42            7 : final alphanum = rule('ALPHANUM', alternatives([alpha, digit]));
      43              : 
      44            4 : final dquote = rule('DQUOTE', character(0x22));
      45              : 
      46            6 : final hexletters = rule(
      47              :   'HEX-LETTERS',
      48              :   // alternativeLiterals is case-insensitive by default (RFC 5234 §2.3),
      49              :   // so uppercase A–F are matched automatically.
      50            4 :   alternativeLiterals(['a', 'b', 'c', 'd', 'e', 'f']),
      51              : );
      52              : 
      53           14 : final hexdig = rule('HEXDIG', alternatives([hexletters, digit]));
      54              : 
      55            4 : final htab = rule('HTAB', character(0x09));
      56              : 
      57            4 : final lf = rule('LF', character(0x0A));
      58              : 
      59            4 : final sp = rule('SP', character(0x20));
      60              : 
      61              : /// Visible (printing) characters (range %x21-7E).
      62            4 : final vchar = rule('VCHAR', valueRange(0x21, 0x7E));
      63              : 
      64            7 : final wsp = rule('WSP', alternatives([sp, htab]));
      65              : 
      66            5 : final optionalWsp = rule('Optional-WSP', variableRepetition(wsp));