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  • identifiers.js

  • §

    Identifiers Reference Guide

  • §

    This file defines a comprehensive set of numerical identifiers used throughout the parsing and translation process. Each identifier is designed for memory-efficient representation and fast lookup, ensuring robust performance of the parser and the application’s callback functions. These constants serve as identifiers for:

  • §
    • Parse Tree Node Operators Representing parse tree node types in the grammar object and in the parser during parsing.
  • §
    • Parser States Identifies parser states during depth-first traversal of the parse tree.
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    • Abstract Syntax Tree (AST) Traversal Flags Identifies directional flow during the depth-first traversal of the AST.
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    • Input String Array Types Allows quick differentiation between the allowed input string array types.
    export { identifiers };
const identifiers = {
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    These identify the operator types in the grammar object as well as the parser. Note: These must match the values in apg-js 4.4.0 generator.

      /* the original seven ABNF operators */
  ALT: 1 /* alternation */,
  CAT: 2 /* concatenation */,
  REP: 3 /* repetition */,
  RNM: 4 /* rule name */,
  TRG: 5 /* terminal range */,
  TBS: 6 /* terminal binary string, case sensitive */,
  TLS: 7 /* terminal literal string, case insensitive */,

  /* the super set, SABNF operators */
  UDT: 11 /* user-defined terminal */,
  AND: 12 /* positive look ahead */,
  NOT: 13 /* negative look ahead */,
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    Used by the parser and the user’s RNM and UDT callback functions. Identifies the parser state as it traverses the parse tree nodes.

    • ACTIVE - indicates the downward direction through the parse tree node.
    • MATCH - indicates a successfully matched phrase, of length > 0
    • EMPTY - indicates a successfully matched empty phrase, length = 0
    • NOMATCH - indicates failure to match any phrase at all
      ACTIVE: 100,
  MATCH: 101,
  EMPTY: 102,
  NOMATCH: 103,
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    Used by AST translator and the application’s callback functions to identify the node visitation states during the depth-first traversal.

    • SEM_PRE - indicates the downward (pre-branch) direction through the AST node.
    • SEM_POST - indicates the upward (post-branch) direction through the AST node.
      SEM_PRE: 200,
  SEM_POST: 201,
  SEM_OK: 300 /* ignored - retained for backwards compatibility */,
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    The input string array type identifiers.

    • UINT8 - Uint8Array
    • UINT16 - Uint16Array
    • UINT32 - Uint32Array
    • ARRAY - Array
      UINT8: 400,
  UINT16: 401,
  UINT32: 402,
  ARRAY: 403,
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    idName translates a numerical identifier into a human-readable name.

    • @param {number} s - an identifier from the list above
    • @returns {string} - the ASCII name of the identifier
      idName: (s) => {
    switch (s) {
      case identifiers.ALT:
        return 'ALT';
      case identifiers.CAT:
        return 'CAT';
      case identifiers.REP:
        return 'REP';
      case identifiers.RNM:
        return 'RNM';
      case identifiers.TRG:
        return 'TRG';
      case identifiers.TBS:
        return 'TBS';
      case identifiers.TLS:
        return 'TLS';
      case identifiers.UDT:
        return 'UDT';
      case identifiers.AND:
        return 'AND';
      case identifiers.NOT:
        return 'NOT';
      case identifiers.ACTIVE:
        return 'ACTIVE';
      case identifiers.EMPTY:
        return 'EMPTY';
      case identifiers.MATCH:
        return 'MATCH';
      case identifiers.NOMATCH:
        return 'NOMATCH';
      case identifiers.SEM_PRE:
        return 'SEM_PRE';
      case identifiers.SEM_POST:
        return 'SEM_POST';
      case identifiers.SEM_OK:
        return 'SEM_OK';
      case identifiers.UINT8:
        return 'UINT8';
      case identifiers.UINT16:
        return 'UINT16';
      case identifiers.UINT32:
        return 'UINT32';
      case identifiers.ARRAY:
        return 'ARRAY';
      default:
        return 'UNRECOGNIZED IDENTIFIER';
    }
  },
};