File: z29.c

package info (click to toggle)
lout 3.25-1
  • links: PTS
  • area: main
  • in suites: woody
  • size: 9,252 kB
  • ctags: 3,152
  • sloc: ansic: 31,182; makefile: 254; awk: 83
file content (830 lines) | stat: -rw-r--r-- 33,236 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
/*@z29.c:Symbol Table:Declarations, hash()@***********************************/
/*                                                                           */
/*  THE LOUT DOCUMENT FORMATTING SYSTEM (VERSION 3.25)                       */
/*  COPYRIGHT (C) 1991, 2001 Jeffrey H. Kingston                             */
/*                                                                           */
/*  Jeffrey H. Kingston (jeff@cs.usyd.edu.au)                                */
/*  Basser Department of Computer Science                                    */
/*  The University of Sydney 2006                                            */
/*  AUSTRALIA                                                                */
/*                                                                           */
/*  This program is free software; you can redistribute it and/or modify     */
/*  it under the terms of the GNU General Public License as published by     */
/*  the Free Software Foundation; either Version 2, or (at your option)      */
/*  any later version.                                                       */
/*                                                                           */
/*  This program is distributed in the hope that it will be useful,          */
/*  but WITHOUT ANY WARRANTY; without even the implied warranty of           */
/*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            */
/*  GNU General Public License for more details.                             */
/*                                                                           */
/*  You should have received a copy of the GNU General Public License        */
/*  along with this program; if not, write to the Free Software              */
/*  Foundation, Inc., 59 Temple Place, Suite 330, Boston MA 02111-1307 USA   */
/*                                                                           */
/*  FILE:         z29.c                                                      */
/*  MODULE:       Symbol Table                                               */
/*  EXTERNS:      InitSym(), PushScope(), PopScope(), SuppressVisible(),     */
/*                UnSuppressVisible(), SuppressScope(), UnSuppressScope(),   */
/*                SwitchScope(), UnSwitchScope(), BodyParAllowed(),          */
/*                BodyParNotAllowed(), InsertSym(), SearchSym(),             */
/*                SymName(), FullSymName(), ChildSym(), CheckSymSpread(),    */
/*                DeleteEverySym()                                           */
/*                                                                           */
/*****************************************************************************/
#include "externs.h"

#define	MAX_STACK	300		/* size of scope stack               */
#define	MAX_TAB		1783		/* size of hash table                */

#define	length(x)	word_font(x)

static	OBJECT		scope[MAX_STACK];		/* the scope stack   */
static	BOOLEAN		npars_only[MAX_STACK];		/* look for NPAR exc */
static	BOOLEAN		vis_only[MAX_STACK];		/* look for visibles */
static	BOOLEAN		body_ok[MAX_STACK];		/* look for body par */
static	BOOLEAN		suppress_scope;			/* suppress scoping  */
static	BOOLEAN		suppress_visible;		/* suppress visible  */
static	int		scope_top;			/* scope stack top   */
static	struct { OBJECT f1, f2; } symtab[MAX_TAB];	/* the hash table    */
#if DEBUG_ON
static	int		sym_spread[MAX_TAB] = { 0 };	/* hash table spread */
static	int		sym_count = 0;			/* symbol count      */
#endif


/*****************************************************************************/
/*                                                                           */
/*  #define hash(str, len, val)                                              */
/*                                                                           */
/*  Set val to the hash value of string str, which has length len.           */
/*  The hash function is just the character sum mod MAX_TAB.                 */
/*  This definition assumes that working variables rlen and x exist.         */
/*                                                                           */
/*****************************************************************************/

#define hash(str, len, val)						\
{ rlen = len;								\
  x    = str;								\
  val  = *x++;								\
  while( --rlen )  val += *x++;						\
  val %= MAX_TAB;							\
}


/*@::InitSym(), PushScope(), PopScope(), SuppressVisible(), etc.@*************/
/*                                                                           */
/*  InitSym()                                                                */
/*                                                                           */
/*  Initialize the symbol table to empty.                                    */
/*                                                                           */
/*****************************************************************************/

void InitSym(void)
{ int i;
  scope_top = 0;
  suppress_scope = FALSE;
  suppress_visible = FALSE;
  for( i = 0;  i < MAX_TAB;  i++ )
    symtab[i].f1 = symtab[i].f2 = (OBJECT) &symtab[i];
} /* end InitSym */


/*****************************************************************************/
/*                                                                           */
/*  PushScope(x, npars, vis)                                                 */
/*  PopScope()                                                               */
/*                                                                           */
/*  Add or remove an OBJECT x (which must be in the symbol table) to or from */
/*  the scope stack.  If npars is TRUE, only the named parameters of x are   */
/*  added to scope.  If vis is TRUE, only visible locals and parameters are  */
/*  added.                                                                   */
/*                                                                           */
/*****************************************************************************/

void PushScope(OBJECT x, BOOLEAN npars, BOOLEAN vis)
{ debug3(DST, DD, "[ PushScope(%s, %s, %s)", SymName(x), bool(npars), bool(vis));
  assert( suppress_scope == FALSE, "PushScope: suppress_scope!" );
  if( scope_top >= MAX_STACK )
  {
#if DEBUG_ON
    int i;
    for( i = 0; i < scope_top; i++ )
      Error(29, 1, "  scope[%2d] = %s", WARN, &fpos(x), i, SymName(scope[i]));
#endif
    Error(29, 2, "scope depth limit exceeded", INTERN, &fpos(x));
  }
  scope[scope_top]      = x;
  npars_only[scope_top] = npars;
  vis_only[scope_top]   = vis;
  body_ok[scope_top]    = FALSE;
  scope_top++;
} /* end PushScope */

void PopScope(void)
{ debug0(DST, DD, "] PopScope()");
  assert( scope_top > 0, "PopScope: tried to pop empty scope stack");
  assert( suppress_scope == FALSE, "PopScope: suppress_scope!" );
  scope_top--;
} /* end PopScope */


/*****************************************************************************/
/*                                                                           */
/*  SuppressVisible()                                                        */
/*  UnSuppressVisible()                                                      */
/*                                                                           */
/*  Make all children of any symbol acceptable, not just the exported ones.  */
/*                                                                           */
/*****************************************************************************/

void SuppressVisible(void)
{ debug0(DST, DD, "[ SuppressVisible()");
  suppress_visible = TRUE;
} /* end SuppressVisible */

void UnSuppressVisible(void)
{ debug0(DST, DD, "] UnSuppressVisible()");
  suppress_visible = FALSE;
} /* end UnSuppressVisible */


/*@::SuppressScope(), UnSuppressScope(), SwitchScope(), UnswitchScope()@******/
/*                                                                           */
/*  SuppressScope()                                                          */
/*  UnSuppressScope()                                                        */
/*                                                                           */
/*  Suppress all scopes (so that all calls to SearchSym fail); and undo it.  */
/*                                                                           */
/*****************************************************************************/


void SuppressScope(void)
{ debug0(DST, DD, "[ SuppressScope()");
  suppress_scope = TRUE;
} /* end SuppressScope */

void UnSuppressScope(void)
{ debug0(DST, DD, "] UnSuppressScope()");
  suppress_scope = FALSE;
} /* end UnSuppressScope */


/*****************************************************************************/
/*                                                                           */
/*  SwitchScope(sym)                                                         */
/*  UnSwitchScope(sym)                                                       */
/*                                                                           */
/*  Switch to the scope of sym (if nilobj, StartSym); and switch back again. */
/*                                                                           */
/*****************************************************************************/

void SwitchScope(OBJECT sym)
{ int i;
  OBJECT new_scopes[MAX_STACK];
  if( sym == nilobj )  PushScope(StartSym, FALSE, FALSE);
  else
  { i = 0;
    while( sym != StartSym )
    { new_scopes[i++] = enclosing(sym);
      sym = enclosing(sym);
    }
    while( i > 0 )  PushScope(new_scopes[--i], FALSE, FALSE);
  }
}

void UnSwitchScope(OBJECT sym)
{ if( sym == nilobj )  PopScope();
  else
  { while( sym != StartSym )
    { PopScope();
      sym = enclosing(sym);
    }
  }
}


/*****************************************************************************/
/*                                                                           */
/*  BodyParAllowed()                                                         */
/*  BodyParNotAllowed()                                                      */
/*                                                                           */
/*  Allow or disallow invocations of the body parameter of the current tos.  */
/*                                                                           */
/*****************************************************************************/

void BodyParAllowed(void)
{ debug0(DST, DD, "BodyParAllowed()");
  body_ok[scope_top-1] = TRUE;
} /* end BodyParAllowed */

void BodyParNotAllowed(void)
{ debug0(DST, DD, "BodyParNotAllowed()");
  body_ok[scope_top-1] = FALSE;
} /* end BodyParNotAllowed */


/*****************************************************************************/
/*                                                                           */
/*  DebugScope(void)                                                         */
/*                                                                           */
/*  Debug print of current scope stack                                       */
/*                                                                           */
/*****************************************************************************/

void DebugScope(void)
{ int i;
  if( suppress_scope )
  {
    debug0(DST, D, "suppressed");
  }
  else for( i = 0;  i < scope_top;  i++ )
  { debug6(DST, D, "%s %s%s%s%s%s",
      i == scope_top - 1 ? "->" : "  ",
      SymName(scope[i]),
      npars_only[i] ? " npars_only" : "",
      vis_only[i]   ? " vis_only"   : "",
      body_ok[i]    ? " body_ok"    : "",
      i == scope_top - 1 && suppress_visible ? " suppress_visible" : "");
  }
} /* end DebugScope */


/*@::ScopeSnapshot()@*********************************************************/
/*                                                                           */
/*  OBJECT GetScopeSnapshot()                                                */
/*  LoadScopeSnapshot(ss)                                                    */
/*  ClearScopeSnapshot(ss)                                                   */
/*                                                                           */
/*  A scope snapshot is a complete record of the state of the scope stack    */
/*  at some moment.  These routines allow you to take a scope snapshot,      */
/*  then subsequently load it (i.e. make it the current scope), then         */
/*  subsequently clear it (i.e. return to whatever was before the Load).     */
/*                                                                           */
/*****************************************************************************/

OBJECT GetScopeSnapshot()
{ OBJECT ss, x;  int i;
  New(ss, ACAT);
  for( i = scope_top-1;  scope[i] != StartSym;  i-- )
  {
    New(x, SCOPE_SNAPSHOT);
    Link(ss, x);
    Link(x, scope[i]);
    ss_npars_only(x) = npars_only[i];
    ss_vis_only(x) = vis_only[i];
    ss_body_ok(x) = body_ok[i];
  }
  ss_suppress(ss) = suppress_visible;
  return ss;
} /* end GetScopeSnapshot */


void LoadScopeSnapshot(OBJECT ss)
{ OBJECT link, x, sym;  BOOLEAN tmp;
  assert( type(ss) == ACAT, "LoadScopeSnapshot: type(ss)!" );
  PushScope(StartSym, FALSE, FALSE);
  for( link = LastDown(ss);  link != ss;  link = PrevDown(link) )
  { Child(x, link);
    assert( type(x) == SCOPE_SNAPSHOT, "LoadScopeSnapshot: type(x)!" );
    Child(sym, Down(x));
    PushScope(sym, ss_npars_only(x), ss_vis_only(x));
    body_ok[scope_top-1] = ss_body_ok(x);
  }
  tmp = suppress_visible;
  suppress_visible = ss_suppress(ss);
  ss_suppress(ss) = tmp;
  debug0(DST, D, "after LoadScopeSnapshot, scope is:")
  ifdebug(DST, D, DebugScope());
} /* end LoadScopeSnapshot */


void ClearScopeSnapshot(OBJECT ss)
{
  while( scope[scope_top-1] != StartSym )
    scope_top--;
  scope_top--;
  suppress_visible = ss_suppress(ss);
} /* end ClearScopeSnapshot */


/*@::InsertSym()@*************************************************************/
/*                                                                           */
/*  OBJECT InsertSym(str, xtype, xfpos, xprecedence, indefinite, xrecursive, */
/*                                         xpredefined, xenclosing, xbody)   */
/*                                                                           */
/*  Insert a new symbol into the table.  Its string value is str.            */
/*  Initialise the symbol as the parameters indicate.                        */
/*  Return a pointer to the new symbol.                                      */
/*  If str is not a valid symbol name, InsertSym prints an error             */
/*  message and does not insert the symbol.                                  */
/*                                                                           */
/*****************************************************************************/

OBJECT InsertSym(FULL_CHAR *str, unsigned char xtype, FILE_POS *xfpos,
unsigned char xprecedence, BOOLEAN xindefinite, BOOLEAN xrecursive,
unsigned xpredefined, OBJECT xenclosing, OBJECT xbody)
{ register int sum, rlen;
  register unsigned char *x;
  OBJECT p, q, s, tmp, link, entry, plink;  int len;

  debug3(DST, DD, "InsertSym( %s, %s, in %s )",
	Image(xtype), str, SymName(xenclosing));
  if( !LexLegalName(str) )
    Error(29, 3, "invalid symbol name %s", WARN, xfpos, str);

  New(s, xtype);
  FposCopy(fpos(s), *xfpos);
  has_body(s)          = FALSE;
  filter(s)            = nilobj;
  use_invocation(s)    = nilobj;
  imports(s)           = nilobj;
  imports_encl(s)      = FALSE;
  right_assoc(s)       = TRUE;
  precedence(s)        = xprecedence;
  indefinite(s)        = xindefinite;
  recursive(s)         = xrecursive;
  predefined(s)        = xpredefined;
  enclosing(s)         = xenclosing;
  sym_body(s)          = xbody;
  base_uses(s)         = nilobj;
  uses(s)              = nilobj;
  marker(s)            = nilobj;
  cross_sym(s)         = nilobj;
  is_extern_target(s)  = FALSE;
  uses_extern_target(s)= FALSE;
  visible(s)           = FALSE;
  uses_galley(s)       = FALSE;
  horiz_galley(s)      = ROWM;
  has_compulsory(s)    = 0;
  is_compulsory(s)     = FALSE;

  uses_count(s)  = 0;
  dirty(s)       = FALSE;
  if( enclosing(s) != nilobj && type(enclosing(s)) == NPAR )
    dirty(s) = dirty(enclosing(s)) = TRUE;

  has_par(s)     = FALSE;
  has_lpar(s)    = FALSE;
  has_rpar(s)    = FALSE;
  if( is_par(type(s)) )  has_par(enclosing(s))  = TRUE;
  if( type(s) == LPAR )  has_lpar(enclosing(s)) = TRUE;
  if( type(s) == RPAR )  has_rpar(enclosing(s)) = TRUE;

  /* assign a code letter between a and z to any NPAR symbol */
  if( type(s) == NPAR )
  { if( LastDown(enclosing(s)) != enclosing(s) )
    { Child(tmp, LastDown(enclosing(s)));
      if( type(tmp) == NPAR )
      { if( npar_code(tmp) == 'z' || npar_code(tmp) == ' ' )
	  npar_code(s) = ' ';
	else
	  npar_code(s) = npar_code(tmp)+1;
      }
      else
	npar_code(s) = 'a';
    }
    else npar_code(s) = 'a';
  }

  has_target(s)  = FALSE;
  force_target(s) = FALSE;
  if( !StringEqual(str, KW_TARGET) ) is_target(s) = FALSE;
  else
  { is_target(s) = has_target(enclosing(s)) = TRUE;

    /* if @Target is found after @Key, take note of external target */
    if( has_key(enclosing(s)) && xbody != nilobj && is_cross(type(xbody)) )
    { if( LastDown(xbody) != Down(xbody) )
      { OBJECT sym;
	Child(sym, Down(xbody));
	if( type(sym) == CLOSURE )
	{ is_extern_target(actual(sym)) = TRUE;
	  uses_extern_target(actual(sym)) = TRUE;
	}
      }
    }
  }

  has_tag(s) = is_tag(s) = FALSE;
  has_key(s) = is_key(s) = FALSE;
  has_optimize(s) = is_optimize(s) = FALSE;
  has_merge(s) = is_merge(s) = FALSE;
  has_enclose(s) = is_enclose(s) = FALSE;
  if( enclosing(s) != nilobj && type(enclosing(s)) == LOCAL )
  {
    if( StringEqual(str, KW_TAG) )
      is_tag(s) = has_tag(enclosing(s)) = dirty(enclosing(s)) = TRUE;

    if( StringEqual(str, KW_OPTIMIZE) )
      is_optimize(s) = has_optimize(enclosing(s)) = TRUE;

    if( StringEqual(str, KW_KEY) )
    { is_key(s) = has_key(enclosing(s)) = dirty(enclosing(s)) = TRUE;

      /* if @Key is found after @Target, take note of external target */
      for( link=Down(enclosing(s));  link!=enclosing(s);  link=NextDown(link) )
      { Child(p, link);
	if( is_target(p) && sym_body(p)!=nilobj && is_cross(type(sym_body(p))) )
	{ OBJECT sym;
	  Child(sym, Down(sym_body(p)));
	  if( type(sym) == CLOSURE )
	  { is_extern_target(actual(sym)) = TRUE;
	    uses_extern_target(actual(sym)) = TRUE;
	  }
	}
      }
    } 

    if( StringEqual(str, KW_MERGE) )
      is_merge(s) = has_merge(enclosing(s)) = TRUE;

    if( StringEqual(str, KW_ENCLOSE) )
      is_enclose(s) = has_enclose(enclosing(s)) = TRUE;
  }

  if( StringEqual(str, KW_FILTER) )
  { if( type(s) != LOCAL || enclosing(s) == StartSym )
      Error(29, 4, "%s must be a local definition", WARN, &fpos(s), str);
    else if( !has_rpar(enclosing(s)) )
      Error(29, 14, "%s must lie within a symbol with a right parameter",
	WARN, &fpos(s), KW_FILTER);
    else
    { filter(enclosing(s)) = s;
      precedence(enclosing(s)) = FILTER_PREC;
    }
  }

  if( type(s) == RPAR && has_body(enclosing(s)) &&
    (is_tag(s) || is_key(s) || is_optimize(s)) )
    Error(29, 5, "a body parameter may not be named %s", WARN, &fpos(s), str);

  if( type(s) == RPAR && has_target(enclosing(s)) &&
    (is_tag(s) || is_key(s) || is_optimize(s)) )
    Error(29, 6, "the right parameter of a galley may not be called %s",
      WARN, &fpos(s), str);

  len = StringLength(str);
  hash(str, len, sum);

  ifdebug(DST, DD, sym_spread[sum]++;  sym_count++);
  entry = (OBJECT) &symtab[sum];
  for( plink = Down(entry);  plink != entry;  plink = NextDown(plink) )
  { Child(p, plink);
    if( length(p) == len && StringEqual(str, string(p)) )
    { for( link = Down(p);  link != p;  link = NextDown(link) )
      {	Child(q, link);
	if( enclosing(s) == enclosing(q) )
	{ Error(29, 7, "symbol %s previously defined at%s",
	    WARN, &fpos(s), str, EchoFilePos(&fpos(q)) );
	  if( AltErrorFormat )
	  {
	    Error(29, 13, "symbol %s previously defined here",
	      WARN, &fpos(q), str);
	  }
	  break;
	}
      }
      goto wrapup;
    }
  }

  /* need a new OBJECT as well as s */
  NewWord(p, WORD, len, xfpos);
  length(p) = len;
  StringCopy(string(p), str);
  Link(entry, p);

 wrapup:
  Link(p, s);
  if( enclosing(s) != nilobj ) Link(enclosing(s), s);
  debug2(DST, DD, "InsertSym Link(%s, %s) and returning.",
		SymName(enclosing(s)), SymName(s));
  return s;
} /* end InsertSym */


/*****************************************************************************/
/*                                                                           */
/*  InsertAlternativeName(str, s, xfpos)                                     */
/*                                                                           */
/*  Insert an alternative name for symbol s.                                 */
/*                                                                           */
/*****************************************************************************/

void InsertAlternativeName(FULL_CHAR *str, OBJECT s, FILE_POS *xfpos)
{ register int sum, rlen;
  register unsigned char *x;
  int len;
  OBJECT entry, link, plink, p, q;
  debug3(DST, DD, "InsertAlternativeName(%s, %s, %s)",
    str, SymName(s), EchoFilePos(xfpos));

  len = StringLength(str);
  hash(str, len, sum);

  ifdebug(DST, DD, sym_spread[sum]++;  sym_count++);
  entry = (OBJECT) &symtab[sum];
  for( plink = Down(entry);  plink != entry;  plink = NextDown(plink) )
  { Child(p, plink);
    if( length(p) == len && StringEqual(str, string(p)) )
    { for( link = Down(p);  link != p;  link = NextDown(link) )
      {	Child(q, link);
	if( enclosing(s) == enclosing(q) )
	{ Error(29, 12, "symbol name %s previously defined at%s",
	    WARN, &fpos(s), str, EchoFilePos(&fpos(q)) );
	  break;
	}
      }
      goto wrapup;
    }
  }

  /* need a new OBJECT as well as s */
  NewWord(p, WORD, len, xfpos);
  length(p) = len;
  StringCopy(string(p), str);
  Link(entry, p);

 wrapup:
  Link(p, s);
  /* not for copies if( enclosing(s) != nilobj ) Link(enclosing(s), s); */
  debug0(DST, DD, "InsertAlternativeName returning.");
} /* end InsertAlternativeName */


/*@::SearchSym(), SymName()@**************************************************/
/*                                                                           */
/*  OBJECT SearchSym(str, len)                                               */
/*                                                                           */
/*  Search the symbol table for str, with length len, and return an          */
/*  OBJECT referencing the entry if found.  Otherwise return nilobj.         */
/*                                                                           */
/*****************************************************************************/

OBJECT SearchSym(FULL_CHAR *str, int len)
{ register int rlen, sum;
  register FULL_CHAR *x, *y;
  OBJECT p, q, link, plink, entry;
  int s;

  debug2(DST, DDD, "SearchSym( %c..., %d )", str[0], len);

  hash(str, len, sum);
  rlen = len;
  entry = (OBJECT) &symtab[sum];
  for( plink = Down(entry);  plink != entry;  plink = NextDown(plink) )
  { Child(p, plink);
    if( rlen == length(p) )
    { x = str;  y = string(p);
      do; while( *x++ == *y++ && --rlen );
      if( rlen == 0 )
      {
	debug1(DST, DDD, "  found %s", string(p));
	s = scope_top;
	do
	{ s--;
	  for( link = Down(p);  link != p;  link = NextDown(link) )
	  { Child(q, link);
	    { debugcond4(DST, DDD, enclosing(q) == scope[s],
	       "  !npars_only[s] = %s, !vis_only[s] = %s, body_ok[s] = %s, !ss = %s",
	       bool(!npars_only[s]), bool(!vis_only[s]), bool(body_ok[s]),
	       bool(!suppress_scope));
	    }
	    if( enclosing(q) == scope[s]
	      && (!npars_only[s] || type(q) == NPAR)
	      && (!vis_only[s] || visible(q) || suppress_visible )
	      && (body_ok[s] || type(q)!=RPAR || !has_body(enclosing(q))
		  || suppress_visible )
	      && (!suppress_scope || StringEqual(string(p), KW_INCLUDE) ||
				     StringEqual(string(p), KW_SYSINCLUDE))
	    )
	    {	debug3(DST, DD, "SearchSym returning %s %s%%%s",
		  Image(type(q)), SymName(q), SymName(enclosing(q)));
		return q;
	    }
	  }
	} while( scope[s] != StartSym );
      }
    }
    rlen = len;
  }
  debug0(DST, DDD, "SearchSym returning <nilobj>");
  return nilobj;
} /* end SearchSym */


/*****************************************************************************/
/*                                                                           */
/*  FULL_CHAR *SymName(s)                                                    */
/*                                                                           */
/*  Return the string value of the name of symbol s.                         */
/*                                                                           */
/*****************************************************************************/

FULL_CHAR *SymName(OBJECT s)
{ OBJECT p;
  if( s == nilobj )  return AsciiToFull("<nilobj>");
  Parent(p, Up(s));
  assert( is_word(type(p)), "SymName: !is_word(type(p))!" );
  return string(p);
} /* end SymName */
	

/*@::FullSymName(), ChildSym()@***********************************************/
/*                                                                           */
/*  FULL_CHAR *FullSymName(x, str)                                           */
/*                                                                           */
/*  Return the path name of symbol x. with str separating each entry.        */
/*                                                                           */
/*****************************************************************************/

FULL_CHAR *FullSymName(OBJECT x, FULL_CHAR *str)
{ OBJECT stack[20];  int i;
  static FULL_CHAR buff[MAX_BUFF], *sname;
  if( x == nilobj )  return AsciiToFull("<nilobj>");
  assert( enclosing(x) != nilobj, "FullSymName: enclosing(x) == nilobj!" );
  for( i = 0;  enclosing(x) != nilobj && i < 20;  i++ )
  { stack[i] = x;
    x = enclosing(x);
  }
  StringCopy(buff, STR_EMPTY);
  for( i--;  i > 0;  i-- )
  { sname = SymName(stack[i]);
    if( StringLength(sname)+StringLength(str)+StringLength(buff) >= MAX_BUFF )
      Error(29, 8, "full name of symbol is too long", FATAL, &fpos(x));
    StringCat(buff, sname);
    StringCat(buff, str);
  }
  sname = SymName(stack[0]);
  if( StringLength(sname) + StringLength(buff) >= MAX_BUFF )
    Error(29, 9, "full name of symbol is too long", FATAL, &fpos(x));
  StringCat(buff, sname);
  return buff;
} /* end FullSymName */


/*****************************************************************************/
/*                                                                           */
/*  OBJECT ChildSym(s, typ)                                                  */
/*                                                                           */
/*  Find the child of symbol s of type typ, either LPAR or RPAR.             */
/*                                                                           */
/*****************************************************************************/

OBJECT ChildSym(OBJECT s, unsigned typ)
{ OBJECT link, y;
  for( link = Down(s);  link != s;  link = NextDown(link) )
  { Child(y, link);
    if( type(y) == typ && enclosing(y) == s )  return y;
  }
  Error(29, 10, "symbol %s has missing %s", FATAL, &fpos(s),
    SymName(s), Image(typ));
  return nilobj;
} /* end ChildSym */


/*****************************************************************************/
/*                                                                           */
/*  OBJECT ChildSymWithCode(s, code)                                         */
/*                                                                           */
/*  Find the child of symbol s with the given npar code, else nil.           */
/*                                                                           */
/*****************************************************************************/

OBJECT ChildSymWithCode(OBJECT s, unsigned char code)
{ OBJECT link, y;
  for( link = Down(actual(s));  link != actual(s);  link = NextDown(link) )
  { Child(y, link);
    if( type(y) == NPAR && enclosing(y) == actual(s) && npar_code(y) == code )
      return y;
  }
  Error(29, 11, "symbol %s has erroneous code %c (database out of date?)",
    FATAL, &fpos(s), SymName(actual(s)), (char) code);
  return nilobj;
} /* end ChildSym */


/*@::CheckSymSpread(), DeleteSymBody()@***************************************/
/*                                                                           */
/*  CheckSymSpread()                                                         */
/*                                                                           */
/*  Check the spread of symbols through the hash table.                      */
/*                                                                           */
/*****************************************************************************/
#if DEBUG_ON

void CheckSymSpread(void)
{ int i, j, sum, usum;  OBJECT entry, plink;
  debug2(DST, DD, "Symbol table spread (table size = %d, symbols = %d):",
    MAX_TAB, sym_count);
  usum = sum = 0;
  for( i = 0;  i < MAX_TAB;  i++ )
  { fprintf(stderr, "%4d: ", i);
    for( j = 1;  j <= sym_spread[i];  j++ )
    { fprintf(stderr, ".");
      sum += j;
    }
    entry = (OBJECT) &symtab[i];
    for( plink=Down(entry), j=1;  plink != entry;  plink=NextDown(plink), j++ )
    { fprintf(stderr, "+");
      usum += j;
    }
    fprintf(stderr, "\n");
  }
  fprintf(stderr, "average length counting duplicate names = %.1f\n",
	(float) sum / sym_count);
  fprintf(stderr, "average length not counting duplicate names = %.1f\n",
	(float) usum / sym_count);
} /* end CheckSymSpread */


/*****************************************************************************/
/*                                                                           */
/*  static DeleteSymBody(s)                                                  */
/*                                                                           */
/*  Delete the body of symbol s.                                             */
/*                                                                           */
/*****************************************************************************/

static void DeleteSymBody(OBJECT s)
{ OBJECT t;
  debug1(DST, DDD, "DeleteSymBody( %s )", SymName(s));
  switch( type(s) )
  {
    case MACRO:	while( sym_body(s) != nilobj )
		{ t = sym_body(s);
		  sym_body(s) = Delete(sym_body(s), PARENT);
		  Dispose(t);
		}
		break;
	
    case LPAR:
    case NPAR:
    case RPAR:
    case LOCAL:	if( sym_body(s) != nilobj ) DisposeObject(sym_body(s));
		break;

    default:	assert1(FALSE, "DeleteSymBody:", Image(type(s)));
		break;
  }
  debug0(DST, DDD, "DeleteSymBody returning.");
} /* end DeleteSymBody */


/*@::DeleteEverySym()@********************************************************/
/*                                                                           */
/*  DeleteEverySym()                                                         */
/*                                                                           */
/*  Delete every symbol in the symbol table.                                 */
/*  Note that we first delete all bodies, then the symbols themselves.       */
/*  This is so that the closures within the bodies have well-defined         */
/*  actual() pointers, even while the symbol table is being disposed.        */
/*  If this is not done, debug output during the disposal gets confused.     */
/*                                                                           */
/*****************************************************************************/

void DeleteEverySym(void)
{ int i, j, load, cost;  OBJECT p, plink, link, x, entry;
  debug0(DST, DD, "DeleteEverySym()");

  /* dispose the bodies of all symbols */
  for( i = 0;  i < MAX_TAB;  i++ )
  { entry = (OBJECT) &symtab[i];
    for( plink = Down(entry);  plink != entry;  plink = NextDown(plink) )
    { Child(p, plink);
      for( link = Down(p);  link != p;  link = NextDown(link) )
      {	Child(x, link);  DeleteSymBody(x);
	/* *** will not work now
	while( base_uses(x) != nilobj )
	{ tmp = base_uses(x);  base_uses(x) = next(tmp);
	  PutMem(tmp, USES_SIZE);
	}
	while( uses(x) != nilobj )
	{ tmp = uses(x);  uses(x) = next(tmp);
	  PutMem(tmp, USES_SIZE);
	}
	*** */
      }
    }
  }

  /* dispose the symbol name strings, gather statistics, and print them */
  load = cost = 0;
  for( i = 0;  i < MAX_TAB;  i++ )
  { j = 1; entry = (OBJECT) &symtab[i];
    while( Down(entry) != entry )
    { load += 1;  cost += j;  j += 1;
      DisposeChild(Down(entry));
    }
  }
  if( load > 0 )
  { debug4(DST, DD, "size = %d, items = %d (%d%%), probes = %.1f",
      MAX_TAB, load, (100*load)/MAX_TAB, (float) cost/load);
  }
  else
  { debug1(DST, DD, "table size = %d, no entries in table", MAX_TAB);
  }
  debug0(DST, DD, "DeleteEverySym returning.");
} /* end DeleteEverySym */
#endif