2.11BSD#431 - /usr/src/new/PORT/B/src/bed/lexi.c

   1: /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1984. */
   2: static char rcsid[] = "$Header: lexi.c,v 2.4 84/10/26 12:01:34 guido Exp $";
   3: 
   4: /*
   5:  * B editor -- Lexical elements (identifiers, keywords, numbers etc.)
   6:  */
   7: 
   8: #include <ctype.h>
   9: 
  10: #include "b.h"
  11: #include "bobj.h"
  12: #include "node.h"
  13: #include "gram.h"
  14: 
  15: 
  16: /*
  17:  * Table defining lexical elements.
  18:  *
  19:  * ********** Indexed by (symbol-LEXICAL).
  20:  */
  21: 
  22: Hidden char lowercase[] = "0123456789'\"abcdefghijklmnopqrstuvwxyz";
  23: Hidden char uppercase[] = "0123456789'\"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  24: Hidden char digits[] = "0123456789";
  25: 
  26: Hidden struct {
  27:     string l_start;
  28:     string l_continue;
  29: } chclass[] = {
  30:     {lowercase+12, lowercase,}, /* IDENT */
  31:     {uppercase+12, uppercase,}, /* KEYWORD */
  32:     {digits, digits,}, /* NUMBER */
  33:     {"\\", "^",}, /* COMMENT */
  34:     {"^`'", "^`'",}, /* TEXT1 */
  35:     {"^`\"", "^`\"",}, /* TEXT2 */
  36:     {".+-*/#^~@|<=>", "",}, /* OPERATORS */
  37:     {"^", "^",}, /* RAW_INPUT */
  38:     {"", "",}, /* SUGGESTION (dummy) */
  39: };
  40: 
  41: #define NCHCLASS (sizeof(chclass)/sizeof(chclass[0]))
  42: 
  43: 
  44: /*
  45:  * Test whether character `c' may start a lexical element with
  46:  * symbolic name `lex'.
  47:  */
  48: 
  49: Visible bool
  50: maystart(c, lex)
  51:     char c;
  52:     int lex;
  53: {
  54:     string cp;
  55: 
  56:     lex -= LEXICAL;
  57:     Assert(lex >= 0);
  58:     if (lex >= NCHCLASS || !isascii(c) || c != ' ' && !isprint(c))
  59:         return No;
  60:     cp = chclass[lex].l_start;
  61:     if (*cp == '^')
  62:         return !index(cp+1, c);
  63:     return index(cp, c) != 0;
  64: }
  65: 
  66: 
  67: /*
  68:  * Test whether character `c' may continue a lexical element with
  69:  * symbolic name `lex'.
  70:  */
  71: 
  72: Visible bool
  73: maycontinue(c, lex)
  74:     char c;
  75:     int lex;
  76: {
  77:     string cp;
  78: 
  79:     lex -= LEXICAL;
  80:     Assert(lex >= 0);
  81:     if (lex >= NCHCLASS || !isascii(c) || c != ' ' && !isprint(c))
  82:         return No;
  83:     cp = chclass[lex].l_continue;
  84:     if (*cp == '^')
  85:         return !index(cp+1, c);
  86:     return index(cp, c) != 0;
  87: }

Defined functions

Defined variables

Defined macros