scanner.h

PL/0源码

(* =========================================================================

    scanner.[h] -- table-driven lexical scanner

    Scanner tables are created by the program makescan, and are linked
    into the compiler in the form of scantab.cc.

    assumptions:
        There is only one 'except' class in the scangen tables, and
            it constitutes the reserve words.
        Tokens never contain NULL characters.
        Case is insignificant.

  ========================================================================= *)

const
    MAX_MAJOR_TOKEN_NUM = 100;
    MAX_MINOR_TOKEN_NUM = 100;
    MAX_STRING_SPACE    = 20000;
    NULL        = 0;
    LINE_FEED   = chr (10); { returned by readChar at EOLN }
    FILE_END    = chr (1);  { returned by readChar at EOF }
    BLANK       = ' ';
    TAB         = '	';
    TAB_WIDTH   = 8;
    MAX_LINE_LENGTH = 133;

type
    MajorTokenNum = 0..MAX_MAJOR_TOKEN_NUM;
    MinorTokenNum = 0..MAX_MINOR_TOKEN_NUM;
    StringSpaceIndex = 0..MAX_STRING_SPACE;
        {this should be an opaque type}