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revision 1.8 by masse, Tue Jan 8 14:17:33 2002 UTC revision 1.131 by masse, Tue Aug 5 09:09:51 2003 UTC
# Line 1  Line 1 
1  /* printf */  /* -*- coding: utf-8; -*- */
2  #include <stdio.h>  /*
3  /* EXIT_SUCCESS */      stack - an interactive interpreter for a stack-based language
4  #include <stdlib.h>      Copyright (C) 2002  Mats Alritzson and Teddy Hogeborn
 /* NULL */  
 #include <stddef.h>  
 /* dlopen, dlsym, dlerror */  
 #include <dlfcn.h>  
5    
6  #define HASHTBLSIZE 65536      This program is free software; you can redistribute it and/or modify
7        it under the terms of the GNU General Public License as published by
8        the Free Software Foundation; either version 2 of the License, or
9        (at your option) any later version.
10    
11  typedef struct stack_item      This program is distributed in the hope that it will be useful,
12  {      but WITHOUT ANY WARRANTY; without even the implied warranty of
13    enum {value, string, ref, func, symbol, list} type;      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14    union {      GNU General Public License for more details.
     void* ptr;  
     int val;  
   } content;  
15    
16    char* id;      You should have received a copy of the GNU General Public License
17    struct stack_item* next;      along with this program; if not, write to the Free Software
18  } stackitem;      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19    
20        Authors: Mats Alritzson <masse@fukt.bth.se>
21                 Teddy Hogeborn <teddy@fukt.bth.se>
22    */
23    
24  typedef stackitem* hashtbl[HASHTBLSIZE];  #include "stack.h"
 typedef void (*funcp)(stackitem**);  
25    
26  void init_hashtbl(hashtbl out_hash)  /* Initialize a newly created environment */
27    void init_env(environment *env)
28  {  {
29    long i;    int i;
30    
31      env->gc_limit= 400000;
32      env->gc_count= 0;
33      env->gc_ref= NULL;
34    
35      env->head= new_val(env);
36    for(i= 0; i<HASHTBLSIZE; i++)    for(i= 0; i<HASHTBLSIZE; i++)
37      out_hash[i]= NULL;      env->symbols[i]= NULL;
38      env->err= 0;
39      env->in_string= NULL;
40      env->free_string= NULL;
41      env->inputstream= stdin;
42      env->interactive= 1;
43    }
44    
45    void printerr(const char* in_string)
46    {
47      fprintf(stderr, "Err: %s\n", in_string);
48  }  }
49    
50  stackitem** hash(hashtbl in_hashtbl, const char* in_string)  /* Returns a pointer to a pointer to an element in the hash table. */
51    symbol **hash(hashtbl in_hashtbl, const char *in_string)
52  {  {
53    long i= 0;    int i= 0;
54    unsigned long out_hash= 0;    unsigned int out_hash= 0;
55    char key= 0;    char key= '\0';
56    stackitem** position;    symbol **position;
57        
58    while(1){    while(1){                     /* Hash in_string */
59      key= in_string[i++];      key= in_string[i++];
60      if(key=='\0')      if(key=='\0')
61        break;        break;
# Line 51  stackitem** hash(hashtbl in_hashtbl, con Line 66  stackitem** hash(hashtbl in_hashtbl, con
66    position= &(in_hashtbl[out_hash]);    position= &(in_hashtbl[out_hash]);
67    
68    while(1){    while(1){
69      if(*position==NULL)      if(*position==NULL)         /* If empty */
70        return position;        return position;
71            
72      if(strcmp(in_string, (*position)->id)==0)      if(strcmp(in_string, (*position)->id)==0) /* If match */
73        return position;        return position;
74    
75      position= &((*position)->next);      position= &((*position)->next); /* Try next */
76    }    }
77  }  }
78    
79    /* Create new value */
80  int push(stackitem** stack_head, stackitem* in_item)  value* new_val(environment *env)
81  {  {
82    in_item->next= *stack_head;    value *nval= malloc(sizeof(value));
83    *stack_head= in_item;    stackitem *nitem= malloc(sizeof(stackitem));
84    return 1;  
85      assert(nval != NULL);
86      assert(nitem != NULL);
87    
88      nval->content.ptr= NULL;
89      nval->type= empty;
90    
91      nitem->item= nval;
92      nitem->next= env->gc_ref;
93    
94      env->gc_ref= nitem;
95    
96      env->gc_count += sizeof(value);
97      nval->gc.flag.mark= 0;
98      nval->gc.flag.protect= 0;
99    
100      return nval;
101  }  }
102    
103  int push_val(stackitem** stack_head, int in_val)  
104    /* Mark values recursively.
105       Marked values are not collected by the GC. */
106    inline void gc_mark(value *val)
107  {  {
108    stackitem* new_item= malloc(sizeof(stackitem));    if(val==NULL || val->gc.flag.mark)
109    new_item->content.val= in_val;      return;
   new_item->type= value;  
110    
111    push(stack_head, new_item);    val->gc.flag.mark= 1;
112    return 1;  
113      if(val->type==tcons) {
114        gc_mark(CAR(val));
115        gc_mark(CDR(val));
116      }
117  }  }
118    
119  int push_cstring(stackitem** stack_head, const char* in_string)  
120    /* Start GC */
121    extern void gc_init(environment *env)
122  {  {
123    stackitem* new_item= malloc(sizeof(stackitem));    stackitem *new_head= NULL, *titem;
124    new_item->content.ptr= malloc(strlen(in_string)+1);    symbol *tsymb;
125    strcpy(new_item->content.ptr, in_string);    int i;
126    new_item->type= string;  
127      if(env->interactive)
128        printf("Garbage collecting.");
129    
130      /* Mark values on stack */
131      gc_mark(env->head);
132    
133      if(env->interactive)
134        printf(".");
135    
136    
137      /* Mark values in hashtable */
138      for(i= 0; i<HASHTBLSIZE; i++)
139        for(tsymb= env->symbols[i]; tsymb!=NULL; tsymb= tsymb->next)
140          if (tsymb->val != NULL)
141            gc_mark(tsymb->val);
142    
143    
144      if(env->interactive)
145        printf(".");
146    
147      env->gc_count= 0;
148    
149      while(env->gc_ref!=NULL) {    /* Sweep unused values */
150    
151        if(!(env->gc_ref->item->gc.no_gc)){ /* neither mark nor protect */
152    
153          /* Remove content */
154          switch(env->gc_ref->item->type){
155          case string:
156            free(env->gc_ref->item->content.string);
157            break;
158          case tcons:
159            free(env->gc_ref->item->content.c);
160            break;
161          case port:
162          case empty:
163          case integer:
164          case tfloat:
165          case func:
166          case symb:
167            /* Symbol strings are freed when walking the hash table */
168            break;
169          }
170    
171          free(env->gc_ref->item);  /* Remove from gc_ref */
172          titem= env->gc_ref->next;
173          free(env->gc_ref);        /* Remove value */
174          env->gc_ref= titem;
175          continue;
176        }
177    #ifdef DEBUG
178        printf("Kept value (%p)", env->gc_ref->item);
179        if(env->gc_ref->item->gc.flag.mark)
180          printf(" (marked)");
181        if(env->gc_ref->item->gc.flag.protect)
182          printf(" (protected)");
183        switch(env->gc_ref->item->type){
184        case integer:
185          printf(" integer: %d", env->gc_ref->item->content.i);
186          break;
187        case func:
188          printf(" func: %p", env->gc_ref->item->content.func);
189          break;
190        case symb:
191          printf(" symb: %s", env->gc_ref->item->content.sym->id);
192          break;
193        case tcons:
194          printf(" tcons: %p\t%p", CAR(env->gc_ref->item),
195                 CDR(env->gc_ref->item));
196          break;
197        default:
198          printf(" <unknown %d>", (env->gc_ref->item->type));
199        }
200        printf("\n");
201    #endif /* DEBUG */
202    
203        /* Keep values */    
204        env->gc_count += sizeof(value);
205        if(env->gc_ref->item->type==string)
206          env->gc_count += strlen(env->gc_ref->item->content.string)+1;
207        
208        titem= env->gc_ref->next;
209        env->gc_ref->next= new_head;
210        new_head= env->gc_ref;
211        new_head->item->gc.flag.mark= 0;
212        env->gc_ref= titem;
213      }
214    
215      if (env->gc_limit < env->gc_count*2)
216        env->gc_limit= env->gc_count*2;
217    
218      env->gc_ref= new_head;
219    
220      if(env->interactive)
221        printf("done (%d bytes still allocated)\n", env->gc_count);
222    
   push(stack_head, new_item);  
   return 1;  
223  }  }
224    
225  int mk_hashentry(hashtbl in_hashtbl, stackitem* in_item, const char* id)  inline void gc_maybe(environment *env)
226  {  {
227    in_item->id= malloc(strlen(id)+1);    if(env->gc_count < env->gc_limit)
228        return;
229      else
230        return gc_init(env);
231    }
232    
233    /* Protect values from GC */
234    void protect(value *val)
235    {
236      if(val==NULL || val->gc.flag.protect)
237        return;
238    
239    strcpy(in_item->id, id);    val->gc.flag.protect= 1;
   push(hash(in_hashtbl, id), in_item);  
240    
241    return 1;    if(val->type==tcons) {
242        protect(CAR(val));
243        protect(CDR(val));
244      }
245  }  }
246    
247  void def_func(hashtbl in_hashtbl, funcp in_func, const char* id)  /* Unprotect values from GC */
248    void unprotect(value *val)
249  {  {
250    stackitem* temp= malloc(sizeof(stackitem));    if(val==NULL || !(val->gc.flag.protect))
251        return;
252    
253    temp->type= func;    val->gc.flag.protect= 0;
   temp->content.ptr= in_func;  
254    
255    mk_hashentry(in_hashtbl, temp, id);    if(val->type==tcons) {
256        unprotect(CAR(val));
257        unprotect(CDR(val));
258      }
259  }  }
260    
261  void def_sym(hashtbl in_hashtbl, const char* id)  /* Push a value onto the stack */
262    void push_val(environment *env, value *val)
263  {  {
264    stackitem* temp= malloc(sizeof(stackitem));    value *new_value= new_val(env);
     
   temp->type= symbol;  
265    
266    mk_hashentry(in_hashtbl, temp, id);    new_value->content.c= malloc(sizeof(pair));
267      assert(new_value->content.c!=NULL);
268      env->gc_count += sizeof(pair);
269      new_value->type= tcons;
270      CAR(new_value)= val;
271      CDR(new_value)= env->head;
272      env->head= new_value;
273  }  }
274    
275  int push_ref(stackitem** stack_head, hashtbl in_hash, const char* in_string)  /* Push an integer onto the stack */
276    void push_int(environment *env, int in_val)
277  {  {
278    static void* handle= NULL;    value *new_value= new_val(env);
279    void* symbol;    
280      new_value->content.i= in_val;
281      new_value->type= integer;
282    
283    stackitem* new_item= malloc(sizeof(stackitem));    push_val(env, new_value);
284    new_item->content.ptr= *hash(in_hash, in_string);  }
   new_item->type= ref;  
285    
286    if(handle==NULL)  /* Push a floating point number onto the stack */
287      handle= dlopen(NULL, RTLD_LAZY);  void push_float(environment *env, float in_val)
288    {
289      value *new_value= new_val(env);
290    
291    if(new_item->content.ptr==NULL) {    new_value->content.f= in_val;
292      symbol= dlsym(handle, in_string);    new_value->type= tfloat;
     if(dlerror()==NULL)  
       def_func(in_hash, symbol, in_string);  
     else  
       def_sym(in_hash, in_string);  
         
     new_item->content.ptr= *hash(in_hash, in_string);  
     new_item->type= ref;  
   }  
293    
294    push(stack_head, new_item);    push_val(env, new_value);
   return 1;  
295  }  }
296    
297  extern void toss(stackitem** stack_head)  /* Copy a string onto the stack. */
298    void push_cstring(environment *env, const char *in_string)
299  {  {
300    stackitem* temp= *stack_head;    value *new_value= new_val(env);
301      int length= strlen(in_string)+1;
302    
303    if((*stack_head)==NULL)    new_value->content.string= malloc(length);
304      return;    assert(new_value != NULL);
305        env->gc_count += length;
306    if((*stack_head)->type==string)    strcpy(new_value->content.string, in_string);
307      free((*stack_head)->content.ptr);    new_value->type= string;
308    
309    *stack_head= (*stack_head)->next;    push_val(env, new_value);
   free(temp);  
310  }  }
311    
312  extern void nl()  /* Mangle a symbol name to a valid C identifier name */
313    char *mangle_str(const char *old_string)
314  {  {
315    printf("\n");    char validchars[]= "0123456789abcdef";
316      char *new_string, *current;
317    
318      new_string= malloc((strlen(old_string)*2)+4);
319      assert(new_string != NULL);
320      strcpy(new_string, "sx_");    /* Stack eXternal */
321      current= new_string+3;
322      while(old_string[0] != '\0'){
323        current[0]= validchars[(unsigned char)(old_string[0])/16];
324        current[1]= validchars[(unsigned char)(old_string[0])%16];
325        current+= 2;
326        old_string++;
327      }
328      current[0]= '\0';
329    
330      return new_string;            /* The caller must free() it */
331  }  }
332    
333  void prin(stackitem** stack_head)  /* Push a symbol onto the stack. */
334    void push_sym(environment *env, const char *in_string)
335  {  {
336    if((*stack_head)==NULL)    value *new_value;             /* A new symbol value */
337      return;    /* ...which might point to... */
338      symbol **new_symbol;          /* (if needed) A new actual symbol */
339      /* ...which, if possible, will be bound to... */
340      value *new_fvalue;            /* (if needed) A new function value */
341      /* ...which will point to... */
342      void *funcptr;                /* A function pointer */
343    
344      static void *handle= NULL;    /* Dynamic linker handle */
345      const char *dlerr;            /* Dynamic linker error */
346      char *mangled;                /* Mangled function name */
347    
348      new_value= new_val(env);
349      protect(new_value);
350      new_fvalue= new_val(env);
351      protect(new_fvalue);
352    
353      /* The new value is a symbol */
354      new_value->type= symb;
355    
356      /* Look up the symbol name in the hash table */
357      new_symbol= hash(env->symbols, in_string);
358      new_value->content.sym= *new_symbol;
359    
360      if(*new_symbol==NULL) { /* If symbol was undefined */
361    
362        /* Create a new symbol */
363        (*new_symbol)= malloc(sizeof(symbol));
364        assert((*new_symbol) != NULL);
365        (*new_symbol)->val= NULL;   /* undefined value */
366        (*new_symbol)->next= NULL;
367        (*new_symbol)->id= malloc(strlen(in_string)+1);
368        assert((*new_symbol)->id != NULL);
369        strcpy((*new_symbol)->id, in_string);
370    
371        /* Intern the new symbol in the hash table */
372        new_value->content.sym= *new_symbol;
373    
374        /* Try to load the symbol name as an external function, to see if
375           we should bind the symbol to a new function pointer value */
376        if(handle==NULL)            /* If no handle */
377          handle= dlopen(NULL, RTLD_LAZY);
378    
379        mangled= mangle_str(in_string); /* mangle the name */
380        funcptr= dlsym(handle, mangled); /* and try to find it */
381    
382        dlerr= dlerror();
383        if(dlerr != NULL) {         /* If no function was found */
384          funcptr= dlsym(handle, in_string); /* Get function pointer */
385          dlerr= dlerror();
386        }
387    
388        if(dlerr==NULL) {           /* If a function was found */
389          new_fvalue->type= func;   /* The new value is a function pointer */
390          new_fvalue->content.func= funcptr; /* Store function pointer */
391          (*new_symbol)->val= new_fvalue; /* Bind the symbol to the new
392                                             function value */
393        }
394    
395        free(mangled);
396      }
397    
398      push_val(env, new_value);
399      unprotect(new_value); unprotect(new_fvalue);
400    }
401    
402    switch((*stack_head)->type) {  /* Print a value */
403    case value:  void print_val(environment *env, value *val, int noquote, stackitem *stack, FILE *stream)
404      printf("%d", (*stack_head)->content.val);  {
405      stackitem *titem, *tstack;
406      int depth;
407    
408      switch(val->type) {
409      case empty:
410        if(fprintf(stream, "[]") < 0){
411          perror("print_val");
412          env->err= 5;
413          return;
414        }
415        break;
416      case integer:
417        if(fprintf(stream, "%d", val->content.i) < 0){
418          perror("print_val");
419          env->err= 5;
420          return;
421        }
422        break;
423      case tfloat:
424        if(fprintf(stream, "%f", val->content.f) < 0){
425          perror("print_val");
426          env->err= 5;
427          return;
428        }
429      break;      break;
430    case string:    case string:
431      printf("%s", (char*)(*stack_head)->content.ptr);      if(noquote){
432          if(fprintf(stream, "%s", val->content.string) < 0){
433            perror("print_val");
434            env->err= 5;
435            return;
436          }
437        } else {                    /* quote */
438          if(fprintf(stream, "\"%s\"", val->content.string) < 0){
439            perror("print_val");
440            env->err= 5;
441            return;
442          }
443        }
444        break;
445      case symb:
446        if(fprintf(stream, "%s", val->content.sym->id) < 0){
447          perror("print_val");
448          env->err= 5;
449          return;
450        }
451      break;      break;
452    case ref:    case func:
453      printf("%s", ((stackitem*)(*stack_head)->content.ptr)->id);      if(fprintf(stream, "#<function %p>", val->content.func) < 0){
454          perror("print_val");
455          env->err= 5;
456          return;
457        }
458      break;      break;
459    case symbol:    case port:
460    default:      if(fprintf(stream, "#<port %p>", val->content.p) < 0){
461      printf("%p", (*stack_head)->content.ptr);        perror("print_val");
462          env->err= 5;
463          return;
464        }
465        break;
466      case tcons:
467        if(fprintf(stream, "[ ") < 0){
468          perror("print_val");
469          env->err= 5;
470          return;
471        }
472        tstack= stack;
473        do {
474          titem=malloc(sizeof(stackitem));
475          assert(titem != NULL);
476          titem->item=val;
477          titem->next=tstack;
478          tstack=titem;             /* Put it on the stack */
479          /* Search a stack of values being printed to see if we are already
480             printing this value */
481          titem=tstack;
482          depth=0;
483          while(titem != NULL && titem->item != CAR(val)){
484            titem=titem->next;
485            depth++;
486          }
487          if(titem != NULL){        /* If we found it on the stack, */
488            if(fprintf(stream, "#%d#", depth) < 0){ /* print a depth reference */
489              perror("print_val");
490              env->err= 5;
491              free(titem);
492              return;
493            }
494          } else {
495            print_val(env, CAR(val), noquote, tstack, stream);
496          }
497          val= CDR(val);
498          switch(val->type){
499          case empty:
500            break;
501          case tcons:
502            /* Search a stack of values being printed to see if we are already
503               printing this value */
504            titem=tstack;
505            depth=0;
506            while(titem != NULL && titem->item != val){
507              titem=titem->next;
508              depth++;
509            }
510            if(titem != NULL){      /* If we found it on the stack, */
511              if(fprintf(stream, " . #%d#", depth) < 0){ /* print a depth reference */
512                perror("print_val");
513                env->err= 5;
514                goto printval_end;
515              }
516            } else {
517              if(fprintf(stream, " ") < 0){
518                perror("print_val");
519                env->err= 5;
520                goto printval_end;
521              }
522            }
523            break;
524          default:
525            if(fprintf(stream, " . ") < 0){ /* Improper list */
526              perror("print_val");
527              env->err= 5;
528              goto printval_end;
529            }
530            print_val(env, val, noquote, tstack, stream);
531          }
532        } while(val->type == tcons && titem == NULL);
533    
534      printval_end:
535    
536        titem=tstack;
537        while(titem != stack){
538          tstack=titem->next;
539          free(titem);
540          titem=tstack;
541        }
542    
543        if(! (env->err)){
544          if(fprintf(stream, " ]") < 0){
545            perror("print_val");
546            env->err= 5;
547          }
548        }
549      break;      break;
550    }    }
551  }  }
552    
553  extern void print(stackitem** stack_head)  /* Swap the two top elements on the stack. */
554    extern void swap(environment *env)
555  {  {
556    prin(stack_head);    value *temp= env->head;
557    toss(stack_head);    
558  }    if(env->head->type == empty || CDR(env->head)->type == empty) {
559        printerr("Too Few Arguments");
560        env->err=1;
561        return;
562      }
563    
564  /* print_stack(stack); */    env->head= CDR(env->head);
565  void print_st(stackitem* stack_head, long counter)    CDR(temp)= CDR(env->head);
566  {    CDR(env->head)= temp;
567    if(stack_head->next != NULL)  }
568      print_st(stack_head->next, counter+1);  
569    /* Recall a value from a symbol, if bound */
570    extern void rcl(environment *env)
571    {
572      value *val;
573    
574      if(env->head->type==empty) {
575        printerr("Too Few Arguments");
576        env->err= 1;
577        return;
578      }
579    
580    printf("%ld: ", counter);    if(CAR(env->head)->type!=symb) {
581    prin(&stack_head);      printerr("Bad Argument Type");
582    nl();      env->err= 2;
583  }      return;
584      }
585    
586  extern void printstack(stackitem** stack_head)    val= CAR(env->head)->content.sym->val;
587  {    if(val == NULL){
588    if(*stack_head != NULL) {      printerr("Unbound Variable");
589      print_st(*stack_head, 1);      env->err= 3;
590      printf("\n");      return;
591    }    }
592      push_val(env, val);           /* Return the symbol's bound value */
593      swap(env);
594      if(env->err) return;
595      toss(env);                    /* toss the symbol */
596      if(env->err) return;
597  }  }
598    
599    
600  extern void eval(stackitem** stack_head)  /* If the top element is a symbol, determine if it's bound to a
601       function value, and if it is, toss the symbol and execute the
602       function. */
603    extern void eval(environment *env)
604  {  {
605    funcp in_func;    funcp in_func;
606      value* temp_val;
607      value* iterator;
608    
609    if((*stack_head)==NULL || (*stack_head)->type!=ref)   eval_start:
610    
611      gc_maybe(env);
612    
613      if(env->head->type==empty) {
614        printerr("Too Few Arguments");
615        env->err= 1;
616        return;
617      }
618    
619      switch(CAR(env->head)->type) {
620        /* if it's a symbol */
621      case symb:
622        rcl(env);                   /* get its contents */
623        if(env->err) return;
624        if(CAR(env->head)->type!=symb){ /* don't recurse symbols */
625          goto eval_start;
626        }
627        return;
628    
629        /* If it's a lone function value, run it */
630      case func:
631        in_func= CAR(env->head)->content.func;
632        toss(env);
633        if(env->err) return;
634        return in_func(env);
635    
636        /* If it's a list */
637      case tcons:
638        temp_val= CAR(env->head);
639        protect(temp_val);
640    
641        toss(env); if(env->err) return;
642        iterator= temp_val;
643        
644        while(iterator->type != empty) {
645          push_val(env, CAR(iterator));
646          
647          if(CAR(env->head)->type==symb
648             && CAR(env->head)->content.sym->id[0]==';') {
649            toss(env);
650            if(env->err) return;
651            
652            if(CDR(iterator)->type == empty){
653              goto eval_start;
654            }
655            eval(env);
656            if(env->err) return;
657          }
658          if (CDR(iterator)->type == empty || CDR(iterator)->type == tcons)
659            iterator= CDR(iterator);
660          else {
661            printerr("Bad Argument Type"); /* Improper list */
662            env->err= 2;
663            return;
664          }
665        }
666        unprotect(temp_val);
667      return;      return;
668    
669    if(((stackitem*)(*stack_head)->content.ptr)->type==func) {    case empty:
670      in_func= (funcp)((stackitem*)(*stack_head)->content.ptr)->content.ptr;      toss(env);
671      toss(stack_head);    case integer:
672      (*in_func)(stack_head);    case tfloat:
673      case string:
674      case port:
675      return;      return;
676    }    }
677  }  }
678    
679  int stack_read(stackitem** stack_head, hashtbl in_hash, char* in_line)  /* List all defined words */
680    extern void words(environment *env)
681  {  {
682    char *temp, *rest;    symbol *temp;
683    int itemp;    int i;
684    size_t inlength= strlen(in_line)+1;    
685    int convert= 0;    for(i= 0; i<HASHTBLSIZE; i++) {
686        temp= env->symbols[i];
687    temp= malloc(inlength);      while(temp!=NULL) {
688    rest= malloc(inlength);  #ifdef DEBUG
689          if (temp->val != NULL && temp->val->gc.flag.protect)
690            printf("(protected) ");
691    #endif /* DEBUG */
692          printf("%s ", temp->id);
693          temp= temp->next;
694        }
695      }
696    }
697    
698    if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest)) >= 1)  /* Quit stack. */
699      push_cstring(stack_head, temp);  extern void quit(environment *env)
700    else if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest)) >= 1)  {
701      push_val(stack_head, itemp);    int i;
   else if((convert= sscanf(in_line, "%[^ ;\n\r]%[^\n\r]", temp, rest)) >= 1)  
     push_ref(stack_head, in_hash, temp);  
   else if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest)) >= 1)  
     if(*temp==';')  
       eval(stack_head);  
702    
703    free(temp);    while(env->head->type != empty)
704        toss(env);
705    
706    if(convert<2) {    if (env->err) return;
707      free(rest);    for(i= 0; i<HASHTBLSIZE; i++) {
708      return 0;      while(env->symbols[i]!= NULL) {
709          forget_sym(&(env->symbols[i]));
710        }
711        env->symbols[i]= NULL;
712    }    }
713      
714    stack_read(stack_head, in_hash, rest);    env->gc_limit= 0;
715      gc_maybe(env);
716    
717      words(env);
718    
719      if(env->free_string!=NULL)
720        free(env->free_string);
721        
722    free(rest);  #ifdef __linux__
723    return 1;    muntrace();
724    #endif
725    
726      exit(EXIT_SUCCESS);
727  }  }
728    
729  extern void pack(stackitem** stack_head)  /* Internal forget function */
730    void forget_sym(symbol **hash_entry)
731  {  {
732    void* delimiter;    symbol *temp;
733    stackitem *iterator, *temp, *pack;  
734      temp= *hash_entry;
735      *hash_entry= (*hash_entry)->next;
736      
737      free(temp->id);
738      free(temp);
739    }
740    
741    /* Only to be called by itself function printstack. */
742    void print_st(environment *env, value *stack_head, long counter)
743    {
744      if(CDR(stack_head)->type != empty)
745        print_st(env, CDR(stack_head), counter+1);
746      printf("%ld: ", counter);
747      print_val(env, CAR(stack_head), 0, NULL, stdout);
748      printf("\n");
749    }
750    
751    if((*stack_head)==NULL)  /* Prints the stack. */
752    extern void printstack(environment *env)
753    {
754      if(env->head->type == empty) {
755        printf("Stack Empty\n");
756      return;      return;
757      }
758    
759      print_st(env, env->head, 1);
760    }
761    
762    delimiter= (*stack_head)->content.ptr;  int main(int argc, char **argv)
763    toss(stack_head);  {
764      environment myenv;
765    
766      int c;                        /* getopt option character */
767    
768    #ifdef __linux__
769      mtrace();
770    #endif
771    
772    iterator= *stack_head;    init_env(&myenv);
773    
774    while(iterator->next!=NULL && iterator->next->content.ptr!=delimiter)    myenv.interactive = isatty(STDIN_FILENO) && isatty(STDOUT_FILENO);
     iterator= iterator->next;  
775    
776    temp= *stack_head;    while ((c = getopt (argc, argv, "i")) != -1)
777    *stack_head= iterator->next;      switch (c)
778    iterator->next= NULL;        {
779          case 'i':
780            myenv.interactive = 1;
781            break;
782          case '?':
783            fprintf (stderr,
784                     "Unknown option character '\\x%x'.\n",
785                     optopt);
786            return EX_USAGE;
787          default:
788            abort ();
789          }
790        
791    if(*stack_head!=NULL && (*stack_head)->content.ptr==delimiter)    if (optind < argc) {
792      toss(stack_head);      myenv.interactive = 0;
793        myenv.inputstream= fopen(argv[optind], "r");
794        if(myenv.inputstream== NULL) {
795          perror(argv[0]);
796          exit (EX_NOINPUT);
797        }
798      }
799    
800    pack= malloc(sizeof(stackitem));    if(myenv.interactive) {
801    pack->type= list;      printf("Stack version $Revision$\n\
802    pack->content.ptr= temp;  Copyright (C) 2002  Mats Alritzson and Teddy Hogeborn\n\
803    Stack comes with ABSOLUTELY NO WARRANTY; for details type 'warranty;'.\n\
804    This is free software, and you are welcome to redistribute it\n\
805    under certain conditions; type 'copying;' for details.\n");
806      }
807    
808    push(stack_head, pack);    while(1) {
809        if(myenv.in_string==NULL) {
810          if (myenv.interactive) {
811            if(myenv.err) {
812              printf("(error %d)\n", myenv.err);
813              myenv.err= 0;
814            }
815            printf("\n");
816            printstack(&myenv);
817            printf("> ");
818          }
819          myenv.err=0;
820        }
821        readstream(&myenv, myenv.inputstream);
822        if (myenv.err) {            /* EOF or other error */
823          myenv.err=0;
824          quit(&myenv);
825        } else if(myenv.head->type!=empty
826                  && CAR(myenv.head)->type==symb
827                  && CAR(myenv.head)->content.sym->id[0] == ';') {
828          toss(&myenv); if(myenv.err) continue;
829          eval(&myenv);
830        } else {
831          gc_maybe(&myenv);
832        }
833      }
834      quit(&myenv);
835      return EXIT_FAILURE;
836  }  }
837    
838  extern void expand(stackitem** stack_head)  /* Return copy of a value */
839    value *copy_val(environment *env, value *old_value)
840  {  {
841    stackitem *temp, *new_head;    value *new_value;
842    
843    if((*stack_head)==NULL || (*stack_head)->type!=list)    if(old_value==NULL)
844      return;      return NULL;
845    
846      new_value= new_val(env);
847      new_value->type= old_value->type;
848    
849      switch(old_value->type){
850      case tfloat:
851      case integer:
852      case func:
853      case symb:
854      case empty:
855      case port:
856        new_value->content= old_value->content;
857        break;
858      case string:
859        new_value->content.string= strdup(old_value->content.string);
860        break;
861      case tcons:
862    
863    new_head= temp= (*stack_head)->content.ptr;      new_value->content.c= malloc(sizeof(pair));
864    toss(stack_head);      assert(new_value->content.c!=NULL);
865        env->gc_count += sizeof(pair);
866    
867    while(temp->next!=NULL)      CAR(new_value)= copy_val(env, CAR(old_value)); /* recurse */
868      temp= temp->next;      CDR(new_value)= copy_val(env, CDR(old_value)); /* recurse */
869        break;
870      }
871    
872    temp->next= *stack_head;    return new_value;
   *stack_head= new_head;  
873  }  }
874    
875  extern void quit()  /* read a line from a stream; used by readline */
876    void readlinestream(environment *env, FILE *stream)
877  {  {
878    exit(EXIT_SUCCESS);    char in_string[101];
879    
880      if(fgets(in_string, 100, stream)==NULL) {
881        push_cstring(env, "");
882        if (! feof(stream)){
883          perror("readline");
884          env->err= 5;
885        }
886      } else {
887        push_cstring(env, in_string);
888      }
889    }
890    
891    /* Reverse (flip) a list */
892    extern void rev(environment *env)
893    {
894      value *old_head, *new_head, *item;
895    
896      if(env->head->type==empty) {
897        printerr("Too Few Arguments");
898        env->err= 1;
899        return;
900      }
901    
902      if(CAR(env->head)->type==empty)
903        return;                     /* Don't reverse an empty list */
904    
905      if(CAR(env->head)->type!=tcons) {
906        printerr("Bad Argument Type");
907        env->err= 2;
908        return;
909      }
910    
911      old_head= CAR(env->head);
912      new_head= new_val(env);
913      while(old_head->type != empty) {
914        item= old_head;
915        old_head= CDR(old_head);
916        CDR(item)= new_head;
917        new_head= item;
918      }
919      CAR(env->head)= new_head;
920  }  }
921    
922  int main()  /* Make a list. */
923    extern void pack(environment *env)
924  {  {
925    stackitem* s= NULL;    value *iterator, *temp, *ending;
926    hashtbl myhash;  
927    char in_string[100];    ending=new_val(env);
928    
929      iterator= env->head;
930      if(iterator->type == empty
931         || (CAR(iterator)->type==symb
932         && CAR(iterator)->content.sym->id[0]=='[')) {
933        temp= ending;
934        toss(env);
935      } else {
936        /* Search for first delimiter */
937        while(CDR(iterator)->type != empty
938              && (CAR(CDR(iterator))->type!=symb
939               || CAR(CDR(iterator))->content.sym->id[0]!='['))
940          iterator= CDR(iterator);
941        
942        /* Extract list */
943        temp= env->head;
944        env->head= CDR(iterator);
945        CDR(iterator)= ending;
946    
947    init_hashtbl(myhash);      if(env->head->type != empty)
948          toss(env);
949      }
950    
951    printf("okidok\n ");    /* Push list */
952    
953    while(fgets(in_string, 100, stdin) != NULL) {    push_val(env, temp);
954      stack_read(&s, myhash, in_string);    rev(env);
955      printf("okidok\n ");  }
956    
957    /* read from a stream; used by "read" and "readport" */
958    void readstream(environment *env, FILE *stream)
959    {
960      const char symbform[]= "%[a-zA-Z0-9!$%*+./:<=>?@^_~-]%n";
961      const char strform[]= "\"%[^\"]\"%n";
962      const char intform[]= "%i%n";
963      const char fltform[]= "%f%n";
964      const char blankform[]= "%*[ \t]%n";
965      const char ebrackform[]= "]%n";
966      const char semicform[]= ";%n";
967      const char bbrackform[]= "[%n";
968    
969      int itemp, readlength= -1;
970      int count= -1;
971      float ftemp;
972      static int depth= 0;
973      char *match;
974      size_t inlength;
975    
976      if(env->in_string==NULL) {
977        if(depth > 0 && env->interactive) {
978          printf("]> ");
979        }
980        readlinestream(env, env->inputstream);
981        if(env->err) return;
982    
983        if((CAR(env->head)->content.string)[0]=='\0'){
984          env->err= 4;              /* "" means EOF */
985          return;
986        }
987        
988        env->in_string= malloc(strlen(CAR(env->head)->content.string)+1);
989        assert(env->in_string != NULL);
990        env->free_string= env->in_string; /* Save the original pointer */
991        strcpy(env->in_string, CAR(env->head)->content.string);
992        toss(env); if(env->err) return;
993      }
994      
995      inlength= strlen(env->in_string)+1;
996      match= malloc(inlength);
997      assert(match != NULL);
998    
999      if(sscanf(env->in_string, blankform, &readlength) != EOF
1000         && readlength != -1) {
1001        ;
1002      } else if(sscanf(env->in_string, fltform, &ftemp, &readlength) != EOF
1003                && readlength != -1) {
1004        if(sscanf(env->in_string, intform, &itemp, &count) != EOF
1005           && count==readlength) {
1006          push_int(env, itemp);
1007        } else {
1008          push_float(env, ftemp);
1009        }
1010      } else if(sscanf(env->in_string, "\"\"%n", &readlength) != EOF
1011                && readlength != -1) {
1012        push_cstring(env, "");
1013      } else if(sscanf(env->in_string, strform, match, &readlength) != EOF
1014                && readlength != -1) {
1015        push_cstring(env, match);
1016      } else if(sscanf(env->in_string, symbform, match, &readlength) != EOF
1017                && readlength != -1) {
1018        push_sym(env, match);
1019      } else if(sscanf(env->in_string, ebrackform, &readlength) != EOF
1020                && readlength != -1) {
1021        pack(env); if(env->err) return;
1022        if(depth != 0) depth--;
1023      } else if(sscanf(env->in_string, semicform, &readlength) != EOF
1024                && readlength != -1) {
1025        push_sym(env, ";");
1026      } else if(sscanf(env->in_string, bbrackform, &readlength) != EOF
1027                && readlength != -1) {
1028        push_sym(env, "[");
1029        depth++;
1030      } else {
1031        free(env->free_string);
1032        env->in_string = env->free_string = NULL;
1033    }    }
1034      if (env->in_string != NULL) {
1035        env->in_string += readlength;
1036      }
1037    
1038      free(match);
1039    
1040      if(depth)
1041        return readstream(env, env->inputstream);
1042    }
1043    
1044    return EXIT_SUCCESS;  extern void copying(environment *env)
1045    {
1046      printf("                  GNU GENERAL PUBLIC LICENSE\n\
1047                           Version 2, June 1991\n\
1048    \n\
1049     Copyright (C) 1989, 1991 Free Software Foundation, Inc.\n\
1050         59 Temple Place, Suite 330, Boston, MA  02111-1307  USA\n\
1051     Everyone is permitted to copy and distribute verbatim copies\n\
1052     of this license document, but changing it is not allowed.\n\
1053    \n\
1054                                Preamble\n\
1055    \n\
1056      The licenses for most software are designed to take away your\n\
1057    freedom to share and change it.  By contrast, the GNU General Public\n\
1058    License is intended to guarantee your freedom to share and change free\n\
1059    software--to make sure the software is free for all its users.  This\n\
1060    General Public License applies to most of the Free Software\n\
1061    Foundation's software and to any other program whose authors commit to\n\
1062    using it.  (Some other Free Software Foundation software is covered by\n\
1063    the GNU Library General Public License instead.)  You can apply it to\n\
1064    your programs, too.\n\
1065    \n\
1066      When we speak of free software, we are referring to freedom, not\n\
1067    price.  Our General Public Licenses are designed to make sure that you\n\
1068    have the freedom to distribute copies of free software (and charge for\n\
1069    this service if you wish), that you receive source code or can get it\n\
1070    if you want it, that you can change the software or use pieces of it\n\
1071    in new free programs; and that you know you can do these things.\n\
1072    \n\
1073      To protect your rights, we need to make restrictions that forbid\n\
1074    anyone to deny you these rights or to ask you to surrender the rights.\n\
1075    These restrictions translate to certain responsibilities for you if you\n\
1076    distribute copies of the software, or if you modify it.\n\
1077    \n\
1078      For example, if you distribute copies of such a program, whether\n\
1079    gratis or for a fee, you must give the recipients all the rights that\n\
1080    you have.  You must make sure that they, too, receive or can get the\n\
1081    source code.  And you must show them these terms so they know their\n\
1082    rights.\n\
1083    \n\
1084      We protect your rights with two steps: (1) copyright the software, and\n\
1085    (2) offer you this license which gives you legal permission to copy,\n\
1086    distribute and/or modify the software.\n\
1087    \n\
1088      Also, for each author's protection and ours, we want to make certain\n\
1089    that everyone understands that there is no warranty for this free\n\
1090    software.  If the software is modified by someone else and passed on, we\n\
1091    want its recipients to know that what they have is not the original, so\n\
1092    that any problems introduced by others will not reflect on the original\n\
1093    authors' reputations.\n\
1094    \n\
1095      Finally, any free program is threatened constantly by software\n\
1096    patents.  We wish to avoid the danger that redistributors of a free\n\
1097    program will individually obtain patent licenses, in effect making the\n\
1098    program proprietary.  To prevent this, we have made it clear that any\n\
1099    patent must be licensed for everyone's free use or not licensed at all.\n\
1100    \n\
1101      The precise terms and conditions for copying, distribution and\n\
1102    modification follow.\n\
1103    \n\
1104                        GNU GENERAL PUBLIC LICENSE\n\
1105       TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION\n\
1106    \n\
1107      0. This License applies to any program or other work which contains\n\
1108    a notice placed by the copyright holder saying it may be distributed\n\
1109    under the terms of this General Public License.  The \"Program\", below,\n\
1110    refers to any such program or work, and a \"work based on the Program\"\n\
1111    means either the Program or any derivative work under copyright law:\n\
1112    that is to say, a work containing the Program or a portion of it,\n\
1113    either verbatim or with modifications and/or translated into another\n\
1114    language.  (Hereinafter, translation is included without limitation in\n\
1115    the term \"modification\".)  Each licensee is addressed as \"you\".\n\
1116    \n\
1117    Activities other than copying, distribution and modification are not\n\
1118    covered by this License; they are outside its scope.  The act of\n\
1119    running the Program is not restricted, and the output from the Program\n\
1120    is covered only if its contents constitute a work based on the\n\
1121    Program (independent of having been made by running the Program).\n\
1122    Whether that is true depends on what the Program does.\n\
1123    \n\
1124      1. You may copy and distribute verbatim copies of the Program's\n\
1125    source code as you receive it, in any medium, provided that you\n\
1126    conspicuously and appropriately publish on each copy an appropriate\n\
1127    copyright notice and disclaimer of warranty; keep intact all the\n\
1128    notices that refer to this License and to the absence of any warranty;\n\
1129    and give any other recipients of the Program a copy of this License\n\
1130    along with the Program.\n\
1131    \n\
1132    You may charge a fee for the physical act of transferring a copy, and\n\
1133    you may at your option offer warranty protection in exchange for a fee.\n\
1134    \n\
1135      2. You may modify your copy or copies of the Program or any portion\n\
1136    of it, thus forming a work based on the Program, and copy and\n\
1137    distribute such modifications or work under the terms of Section 1\n\
1138    above, provided that you also meet all of these conditions:\n\
1139    \n\
1140        a) You must cause the modified files to carry prominent notices\n\
1141        stating that you changed the files and the date of any change.\n\
1142    \n\
1143        b) You must cause any work that you distribute or publish, that in\n\
1144        whole or in part contains or is derived from the Program or any\n\
1145        part thereof, to be licensed as a whole at no charge to all third\n\
1146        parties under the terms of this License.\n\
1147    \n\
1148        c) If the modified program normally reads commands interactively\n\
1149        when run, you must cause it, when started running for such\n\
1150        interactive use in the most ordinary way, to print or display an\n\
1151        announcement including an appropriate copyright notice and a\n\
1152        notice that there is no warranty (or else, saying that you provide\n\
1153        a warranty) and that users may redistribute the program under\n\
1154        these conditions, and telling the user how to view a copy of this\n\
1155        License.  (Exception: if the Program itself is interactive but\n\
1156        does not normally print such an announcement, your work based on\n\
1157        the Program is not required to print an announcement.)\n\
1158    \n\
1159    These requirements apply to the modified work as a whole.  If\n\
1160    identifiable sections of that work are not derived from the Program,\n\
1161    and can be reasonably considered independent and separate works in\n\
1162    themselves, then this License, and its terms, do not apply to those\n\
1163    sections when you distribute them as separate works.  But when you\n\
1164    distribute the same sections as part of a whole which is a work based\n\
1165    on the Program, the distribution of the whole must be on the terms of\n\
1166    this License, whose permissions for other licensees extend to the\n\
1167    entire whole, and thus to each and every part regardless of who wrote it.\n\
1168    \n\
1169    Thus, it is not the intent of this section to claim rights or contest\n\
1170    your rights to work written entirely by you; rather, the intent is to\n\
1171    exercise the right to control the distribution of derivative or\n\
1172    collective works based on the Program.\n\
1173    \n\
1174    In addition, mere aggregation of another work not based on the Program\n\
1175    with the Program (or with a work based on the Program) on a volume of\n\
1176    a storage or distribution medium does not bring the other work under\n\
1177    the scope of this License.\n\
1178    \n\
1179      3. You may copy and distribute the Program (or a work based on it,\n\
1180    under Section 2) in object code or executable form under the terms of\n\
1181    Sections 1 and 2 above provided that you also do one of the following:\n\
1182    \n\
1183        a) Accompany it with the complete corresponding machine-readable\n\
1184        source code, which must be distributed under the terms of Sections\n\
1185        1 and 2 above on a medium customarily used for software interchange; or,\n\
1186    \n\
1187        b) Accompany it with a written offer, valid for at least three\n\
1188        years, to give any third party, for a charge no more than your\n\
1189        cost of physically performing source distribution, a complete\n\
1190        machine-readable copy of the corresponding source code, to be\n\
1191        distributed under the terms of Sections 1 and 2 above on a medium\n\
1192        customarily used for software interchange; or,\n\
1193    \n\
1194        c) Accompany it with the information you received as to the offer\n\
1195        to distribute corresponding source code.  (This alternative is\n\
1196        allowed only for noncommercial distribution and only if you\n\
1197        received the program in object code or executable form with such\n\
1198        an offer, in accord with Subsection b above.)\n\
1199    \n\
1200    The source code for a work means the preferred form of the work for\n\
1201    making modifications to it.  For an executable work, complete source\n\
1202    code means all the source code for all modules it contains, plus any\n\
1203    associated interface definition files, plus the scripts used to\n\
1204    control compilation and installation of the executable.  However, as a\n\
1205    special exception, the source code distributed need not include\n\
1206    anything that is normally distributed (in either source or binary\n\
1207    form) with the major components (compiler, kernel, and so on) of the\n\
1208    operating system on which the executable runs, unless that component\n\
1209    itself accompanies the executable.\n\
1210    \n\
1211    If distribution of executable or object code is made by offering\n\
1212    access to copy from a designated place, then offering equivalent\n\
1213    access to copy the source code from the same place counts as\n\
1214    distribution of the source code, even though third parties are not\n\
1215    compelled to copy the source along with the object code.\n\
1216    \n\
1217      4. You may not copy, modify, sublicense, or distribute the Program\n\
1218    except as expressly provided under this License.  Any attempt\n\
1219    otherwise to copy, modify, sublicense or distribute the Program is\n\
1220    void, and will automatically terminate your rights under this License.\n\
1221    However, parties who have received copies, or rights, from you under\n\
1222    this License will not have their licenses terminated so long as such\n\
1223    parties remain in full compliance.\n\
1224    \n\
1225      5. You are not required to accept this License, since you have not\n\
1226    signed it.  However, nothing else grants you permission to modify or\n\
1227    distribute the Program or its derivative works.  These actions are\n\
1228    prohibited by law if you do not accept this License.  Therefore, by\n\
1229    modifying or distributing the Program (or any work based on the\n\
1230    Program), you indicate your acceptance of this License to do so, and\n\
1231    all its terms and conditions for copying, distributing or modifying\n\
1232    the Program or works based on it.\n\
1233    \n\
1234      6. Each time you redistribute the Program (or any work based on the\n\
1235    Program), the recipient automatically receives a license from the\n\
1236    original licensor to copy, distribute or modify the Program subject to\n\
1237    these terms and conditions.  You may not impose any further\n\
1238    restrictions on the recipients' exercise of the rights granted herein.\n\
1239    You are not responsible for enforcing compliance by third parties to\n\
1240    this License.\n\
1241    \n\
1242      7. If, as a consequence of a court judgment or allegation of patent\n\
1243    infringement or for any other reason (not limited to patent issues),\n\
1244    conditions are imposed on you (whether by court order, agreement or\n\
1245    otherwise) that contradict the conditions of this License, they do not\n\
1246    excuse you from the conditions of this License.  If you cannot\n\
1247    distribute so as to satisfy simultaneously your obligations under this\n\
1248    License and any other pertinent obligations, then as a consequence you\n\
1249    may not distribute the Program at all.  For example, if a patent\n\
1250    license would not permit royalty-free redistribution of the Program by\n\
1251    all those who receive copies directly or indirectly through you, then\n\
1252    the only way you could satisfy both it and this License would be to\n\
1253    refrain entirely from distribution of the Program.\n\
1254    \n\
1255    If any portion of this section is held invalid or unenforceable under\n\
1256    any particular circumstance, the balance of the section is intended to\n\
1257    apply and the section as a whole is intended to apply in other\n\
1258    circumstances.\n\
1259    \n\
1260    It is not the purpose of this section to induce you to infringe any\n\
1261    patents or other property right claims or to contest validity of any\n\
1262    such claims; this section has the sole purpose of protecting the\n\
1263    integrity of the free software distribution system, which is\n\
1264    implemented by public license practices.  Many people have made\n\
1265    generous contributions to the wide range of software distributed\n\
1266    through that system in reliance on consistent application of that\n\
1267    system; it is up to the author/donor to decide if he or she is willing\n\
1268    to distribute software through any other system and a licensee cannot\n\
1269    impose that choice.\n\
1270    \n\
1271    This section is intended to make thoroughly clear what is believed to\n\
1272    be a consequence of the rest of this License.\n\
1273    \n\
1274      8. If the distribution and/or use of the Program is restricted in\n\
1275    certain countries either by patents or by copyrighted interfaces, the\n\
1276    original copyright holder who places the Program under this License\n\
1277    may add an explicit geographical distribution limitation excluding\n\
1278    those countries, so that distribution is permitted only in or among\n\
1279    countries not thus excluded.  In such case, this License incorporates\n\
1280    the limitation as if written in the body of this License.\n\
1281    \n\
1282      9. The Free Software Foundation may publish revised and/or new versions\n\
1283    of the General Public License from time to time.  Such new versions will\n\
1284    be similar in spirit to the present version, but may differ in detail to\n\
1285    address new problems or concerns.\n\
1286    \n\
1287    Each version is given a distinguishing version number.  If the Program\n\
1288    specifies a version number of this License which applies to it and \"any\n\
1289    later version\", you have the option of following the terms and conditions\n\
1290    either of that version or of any later version published by the Free\n\
1291    Software Foundation.  If the Program does not specify a version number of\n\
1292    this License, you may choose any version ever published by the Free Software\n\
1293    Foundation.\n\
1294    \n\
1295      10. If you wish to incorporate parts of the Program into other free\n\
1296    programs whose distribution conditions are different, write to the author\n\
1297    to ask for permission.  For software which is copyrighted by the Free\n\
1298    Software Foundation, write to the Free Software Foundation; we sometimes\n\
1299    make exceptions for this.  Our decision will be guided by the two goals\n\
1300    of preserving the free status of all derivatives of our free software and\n\
1301    of promoting the sharing and reuse of software generally.\n");
1302    }
1303    
1304    extern void warranty(environment *env)
1305    {
1306      printf("                          NO WARRANTY\n\
1307    \n\
1308      11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY\n\
1309    FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN\n\
1310    OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES\n\
1311    PROVIDE THE PROGRAM \"AS IS\" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED\n\
1312    OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF\n\
1313    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS\n\
1314    TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE\n\
1315    PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,\n\
1316    REPAIR OR CORRECTION.\n\
1317    \n\
1318      12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING\n\
1319    WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR\n\
1320    REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,\n\
1321    INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING\n\
1322    OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED\n\
1323    TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY\n\
1324    YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER\n\
1325    PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE\n\
1326    POSSIBILITY OF SUCH DAMAGES.\n");
1327    }
1328    
1329    /* Discard the top element of the stack. */
1330    extern void toss(environment *env)
1331    {
1332      if(env->head->type==empty) {
1333        printerr("Too Few Arguments");
1334        env->err= 1;
1335        return;
1336      }
1337      
1338      env->head= CDR(env->head); /* Remove the top stack item */
1339  }  }
1340    
 /* Local Variables: */  
 /* compile-command:"make CFLAGS=\"-Wall -g -rdynamic -ldl\" stack" */  
 /* End: */  
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