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revision 1.89 by masse, Sun Feb 17 04:03:57 2002 UTC revision 1.126 by masse, Mon Aug 4 11:22:02 2003 UTC
# Line 1  Line 1 
1  /* printf, sscanf, fgets, fprintf, fopen, perror */  /* -*- coding: utf-8; -*- */
2  #include <stdio.h>  /*
3  /* exit, EXIT_SUCCESS, malloc, free */      stack - an interactive interpreter for a stack-based language
4  #include <stdlib.h>      Copyright (C) 2002  Mats Alritzson and Teddy Hogeborn
5  /* NULL */  
6  #include <stddef.h>      This program is free software; you can redistribute it and/or modify
7  /* dlopen, dlsym, dlerror */      it under the terms of the GNU General Public License as published by
8  #include <dlfcn.h>      the Free Software Foundation; either version 2 of the License, or
9  /* strcmp, strcpy, strlen, strcat, strdup */      (at your option) any later version.
10  #include <string.h>  
11  /* getopt, STDIN_FILENO, STDOUT_FILENO */      This program is distributed in the hope that it will be useful,
12  #include <unistd.h>      but WITHOUT ANY WARRANTY; without even the implied warranty of
13  /* EX_NOINPUT, EX_USAGE */      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  #include <sysexits.h>      GNU General Public License for more details.
15  /* mtrace, muntrace */  
16  #include <mcheck.h>      You should have received a copy of the GNU General Public License
17        along with this program; if not, write to the Free Software
18        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  #include "stack.h"  #include "stack.h"
25    
# Line 22  void init_env(environment *env) Line 28  void init_env(environment *env)
28  {  {
29    int i;    int i;
30    
31    env->gc_limit= 20;    env->gc_limit= 400000;
32    env->gc_count= 0;    env->gc_count= 0;
33      env->gc_ref= NULL;
34    
35    env->head= NULL;    env->head= new_val(env);
36    for(i= 0; i<HASHTBLSIZE; i++)    for(i= 0; i<HASHTBLSIZE; i++)
37      env->symbols[i]= NULL;      env->symbols[i]= NULL;
38    env->err= 0;    env->err= 0;
# Line 35  void init_env(environment *env) Line 42  void init_env(environment *env)
42    env->interactive= 1;    env->interactive= 1;
43  }  }
44    
45  void printerr(const char* in_string) {  void printerr(const char* in_string)
   fprintf(stderr, "Err: %s\n", in_string);  
 }  
   
 /* Discard the top element of the stack. */  
 extern void toss(environment *env)  
46  {  {
47    stackitem *temp= env->head;    fprintf(stderr, "Err: %s\n", in_string);
   
   if((env->head)==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
     
   env->head= env->head->next;   /* Remove the top stack item */  
   free(temp);                   /* Free the old top stack item */  
48  }  }
49    
50  /* Returns a pointer to a pointer to an element in the hash table. */  /* Returns a pointer to a pointer to an element in the hash table. */
# Line 83  symbol **hash(hashtbl in_hashtbl, const Line 76  symbol **hash(hashtbl in_hashtbl, const
76    }    }
77  }  }
78    
79  value* new_val(environment *env) {  /* Create new value */
80    value* new_val(environment *env)
81    {
82    value *nval= malloc(sizeof(value));    value *nval= malloc(sizeof(value));
83    stackitem *nitem= malloc(sizeof(stackitem));    stackitem *nitem= malloc(sizeof(stackitem));
84    
85      assert(nval != NULL);
86      assert(nitem != NULL);
87    
88    nval->content.ptr= NULL;    nval->content.ptr= NULL;
89      nval->type= empty;
90    
91    nitem->item= nval;    nitem->item= nval;
92    nitem->next= env->gc_ref;    nitem->next= env->gc_ref;
93    
94    env->gc_ref= nitem;    env->gc_ref= nitem;
95    
96    env->gc_count++;    env->gc_count += sizeof(value);
97      nval->gc.flag.mark= 0;
98      nval->gc.flag.protect= 0;
99    
100    return nval;    return nval;
101  }  }
102    
 void gc_mark(value *val) {  
   stackitem *iterator;  
103    
104    if(val==NULL || val->gc_garb==0)  /* Mark values recursively.
105       Marked values are not collected by the GC. */
106    inline void gc_mark(value *val)
107    {
108      if(val==NULL || val->gc.flag.mark)
109      return;      return;
110    
111    val->gc_garb= 0;    val->gc.flag.mark= 1;
   
   if(val->type==list) {  
     iterator= val->content.ptr;  
112    
113      while(iterator!=NULL) {    if(val->type==tcons) {
114        gc_mark(iterator->item);      gc_mark(CAR(val));
115        iterator= iterator->next;      gc_mark(CDR(val));
     }  
116    }    }
117  }  }
118    
119  extern void gc_init(environment *env) {  
120    stackitem *new_head= NULL, *titem, *iterator= env->gc_ref;  /* Start GC */
121    extern void gc_init(environment *env)
122    {
123      stackitem *new_head= NULL, *titem;
124    symbol *tsymb;    symbol *tsymb;
125    int i;    int i;
126    
127    if(env->gc_count < env->gc_limit)    if(env->interactive)
128      return;      printf("Garbage collecting.");
129    
130    while(iterator!=NULL) {    /* Mark values on stack */
131      iterator->item->gc_garb= 1;    gc_mark(env->head);
     iterator= iterator->next;  
   }  
132    
133    /* Mark */    if(env->interactive)
134    iterator= env->head;      printf(".");
   while(iterator!=NULL) {  
     gc_mark(iterator->item);  
     iterator= iterator->next;  
   }  
135    
136    for(i= 0; i<HASHTBLSIZE; i++) {  
137      tsymb= env->symbols[i];    /* Mark values in hashtable */
138      while(tsymb!=NULL) {    for(i= 0; i<HASHTBLSIZE; i++)
139        gc_mark(tsymb->val);      for(tsymb= env->symbols[i]; tsymb!=NULL; tsymb= tsymb->next)
140        tsymb= tsymb->next;        if (tsymb->val != NULL)
141      }          gc_mark(tsymb->val);
142    }  
143    
144      if(env->interactive)
145        printf(".");
146    
147    env->gc_count= 0;    env->gc_count= 0;
148    
149    /* Sweep */    while(env->gc_ref!=NULL) {    /* Sweep unused values */
150    while(env->gc_ref!=NULL) {  
151      if(env->gc_ref->item->gc_garb) {      if(!(env->gc_ref->item->gc.no_gc)){ /* neither mark nor protect */
152        switch(env->gc_ref->item->type) {  
153          /* Remove content */
154          switch(env->gc_ref->item->type){
155        case string:        case string:
156          free(env->gc_ref->item->content.ptr);          free(env->gc_ref->item->content.ptr);
157          break;          break;
158        case integer:        case tcons:
159          break;          free(env->gc_ref->item->content.c);
       case list:  
         while(env->gc_ref->item->content.ptr!=NULL) {  
           titem= env->gc_ref->item->content.ptr;  
           env->gc_ref->item->content.ptr= titem->next;  
           free(titem);  
         }  
160          break;          break;
161        default:        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;          break;
169        }        }
170        free(env->gc_ref->item);  
171        titem= env->gc_ref->next;        free(env->gc_ref->item);  /* Remove from gc_ref */
       free(env->gc_ref);  
       env->gc_ref= titem;  
     } else {  
172        titem= env->gc_ref->next;        titem= env->gc_ref->next;
173        env->gc_ref->next= new_head;        free(env->gc_ref);        /* Remove value */
       new_head= env->gc_ref;  
174        env->gc_ref= titem;        env->gc_ref= titem;
175        env->gc_count++;        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.ptr);
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", env->gc_ref->item->content.c->car,
195                 env->gc_ref->item->content.c->cdr);
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.ptr)+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    env->gc_limit= env->gc_count*2;    if (env->gc_limit < env->gc_count*2)
216        env->gc_limit= env->gc_count*2;
217    
218    env->gc_ref= new_head;    env->gc_ref= new_head;
219    
220      if(env->interactive)
221        printf("done (%d bytes still allocated)\n", env->gc_count);
222    
223    }
224    
225    inline void gc_maybe(environment *env)
226    {
227      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      val->gc.flag.protect= 1;
240    
241      if(val->type==tcons) {
242        protect(CAR(val));
243        protect(CDR(val));
244      }
245    }
246    
247    /* Unprotect values from GC */
248    void unprotect(value *val)
249    {
250      if(val==NULL || !(val->gc.flag.protect))
251        return;
252    
253      val->gc.flag.protect= 0;
254    
255      if(val->type==tcons) {
256        unprotect(CAR(val));
257        unprotect(CDR(val));
258      }
259  }  }
260    
261  /* Push a value onto the stack */  /* Push a value onto the stack */
262  void push_val(environment *env, value *val)  void push_val(environment *env, value *val)
263  {  {
264    stackitem *new_item= malloc(sizeof(stackitem));    value *new_value= new_val(env);
265    new_item->item= val;  
266    new_item->next= env->head;    new_value->content.c= malloc(sizeof(pair));
267    env->head= new_item;    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  /* Push an integer onto the stack. */  /* Push an integer onto the stack */
276  void push_int(environment *env, int in_val)  void push_int(environment *env, int in_val)
277  {  {
278    value *new_value= new_val(env);    value *new_value= new_val(env);
279        
280    new_value->content.val= in_val;    new_value->content.i= in_val;
281    new_value->type= integer;    new_value->type= integer;
282    
283    push_val(env, new_value);    push_val(env, new_value);
284  }  }
285    
286    /* Push a floating point number onto the stack */
287    void push_float(environment *env, float in_val)
288    {
289      value *new_value= new_val(env);
290    
291      new_value->content.f= in_val;
292      new_value->type= tfloat;
293    
294      push_val(env, new_value);
295    }
296    
297  /* Copy a string onto the stack. */  /* Copy a string onto the stack. */
298  void push_cstring(environment *env, const char *in_string)  void push_cstring(environment *env, const char *in_string)
299  {  {
300    value *new_value= new_val(env);    value *new_value= new_val(env);
301      int length= strlen(in_string)+1;
302    
303    new_value->content.ptr= malloc(strlen(in_string)+1);    new_value->content.ptr= malloc(length);
304      assert(new_value != NULL);
305      env->gc_count += length;
306    strcpy(new_value->content.ptr, in_string);    strcpy(new_value->content.ptr, in_string);
307    new_value->type= string;    new_value->type= string;
308    
# Line 215  void push_cstring(environment *env, cons Line 310  void push_cstring(environment *env, cons
310  }  }
311    
312  /* Mangle a symbol name to a valid C identifier name */  /* Mangle a symbol name to a valid C identifier name */
313  char *mangle_str(const char *old_string){  char *mangle_str(const char *old_string)
314    char validchars[]  {
315      ="0123456789abcdef";    char validchars[]= "0123456789abcdef";
316    char *new_string, *current;    char *new_string, *current;
317    
318    new_string=malloc((strlen(old_string)*2)+4);    new_string= malloc((strlen(old_string)*2)+4);
319      assert(new_string != NULL);
320    strcpy(new_string, "sx_");    /* Stack eXternal */    strcpy(new_string, "sx_");    /* Stack eXternal */
321    current=new_string+3;    current= new_string+3;
322    while(old_string[0] != '\0'){    while(old_string[0] != '\0'){
323      current[0]=validchars[(unsigned char)(old_string[0])/16];      current[0]= validchars[(unsigned char)(old_string[0])/16];
324      current[1]=validchars[(unsigned char)(old_string[0])%16];      current[1]= validchars[(unsigned char)(old_string[0])%16];
325      current+=2;      current+= 2;
326      old_string++;      old_string++;
327    }    }
328    current[0]='\0';    current[0]= '\0';
329    
330    return new_string;            /* The caller must free() it */    return new_string;            /* The caller must free() it */
331  }  }
332    
333  extern void mangle(environment *env){  extern void mangle(environment *env)
334    {
335    char *new_string;    char *new_string;
336    
337    if((env->head)==NULL) {    if(env->head->type==empty) {
338      printerr("Too Few Arguments");      printerr("Too Few Arguments");
339      env->err=1;      env->err= 1;
340      return;      return;
341    }    }
342    
343    if(env->head->item->type!=string) {    if(CAR(env->head)->type!=string) {
344      printerr("Bad Argument Type");      printerr("Bad Argument Type");
345      env->err=2;      env->err= 2;
346      return;      return;
347    }    }
348    
349    new_string= mangle_str((const char *)(env->head->item->content.ptr));    new_string=
350        mangle_str((const char *)(CAR(env->head)->content.ptr));
351    
352    toss(env);    toss(env);
353    if(env->err) return;    if(env->err) return;
# Line 273  void push_sym(environment *env, const ch Line 371  void push_sym(environment *env, const ch
371    char *mangled;                /* Mangled function name */    char *mangled;                /* Mangled function name */
372    
373    new_value= new_val(env);    new_value= new_val(env);
374      protect(new_value);
375      new_fvalue= new_val(env);
376      protect(new_fvalue);
377    
378    /* The new value is a symbol */    /* The new value is a symbol */
379    new_value->type= symb;    new_value->type= symb;
# Line 285  void push_sym(environment *env, const ch Line 386  void push_sym(environment *env, const ch
386    
387      /* Create a new symbol */      /* Create a new symbol */
388      (*new_symbol)= malloc(sizeof(symbol));      (*new_symbol)= malloc(sizeof(symbol));
389        assert((*new_symbol) != NULL);
390      (*new_symbol)->val= NULL;   /* undefined value */      (*new_symbol)->val= NULL;   /* undefined value */
391      (*new_symbol)->next= NULL;      (*new_symbol)->next= NULL;
392      (*new_symbol)->id= malloc(strlen(in_string)+1);      (*new_symbol)->id= malloc(strlen(in_string)+1);
393        assert((*new_symbol)->id != NULL);
394      strcpy((*new_symbol)->id, in_string);      strcpy((*new_symbol)->id, in_string);
395    
396      /* Intern the new symbol in the hash table */      /* Intern the new symbol in the hash table */
# Line 298  void push_sym(environment *env, const ch Line 401  void push_sym(environment *env, const ch
401      if(handle==NULL)            /* If no handle */      if(handle==NULL)            /* If no handle */
402        handle= dlopen(NULL, RTLD_LAZY);        handle= dlopen(NULL, RTLD_LAZY);
403    
404      mangled=mangle_str(in_string); /* mangle the name */      mangled= mangle_str(in_string); /* mangle the name */
405      funcptr= dlsym(handle, mangled); /* and try to find it */      funcptr= dlsym(handle, mangled); /* and try to find it */
406      free(mangled);  
407      dlerr=dlerror();      dlerr= dlerror();
408      if(dlerr != NULL) {         /* If no function was found */      if(dlerr != NULL) {         /* If no function was found */
409        funcptr= dlsym(handle, in_string); /* Get function pointer */        funcptr= dlsym(handle, in_string); /* Get function pointer */
410        dlerr=dlerror();        dlerr= dlerror();
411      }      }
412    
413      if(dlerr==NULL) {           /* If a function was found */      if(dlerr==NULL) {           /* If a function was found */
414        new_fvalue= new_val(env); /* Create a new value */        new_fvalue->type= func;   /* The new value is a function pointer */
415        new_fvalue->type=func;    /* The new value is a function pointer */        new_fvalue->content.ptr= funcptr; /* Store function pointer */
       new_fvalue->content.ptr=funcptr; /* Store function pointer */  
416        (*new_symbol)->val= new_fvalue; /* Bind the symbol to the new        (*new_symbol)->val= new_fvalue; /* Bind the symbol to the new
417                                           function value */                                           function value */
418      }      }
419    
420        free(mangled);
421    }    }
422    
423    push_val(env, new_value);    push_val(env, new_value);
424      unprotect(new_value); unprotect(new_fvalue);
425  }  }
426    
427  /* Print newline. */  /* Print a value */
428  extern void nl()  void print_val(environment *env, value *val, int noquote, stackitem *stack, FILE *stream)
429  {  {
430    printf("\n");    stackitem *titem, *tstack;
431  }    int depth;
   
 /* Gets the type of a value */  
 extern void type(environment *env){  
   int typenum;  
432    
433    if((env->head)==NULL) {    switch(val->type) {
434      printerr("Too Few Arguments");    case empty:
435      env->err=1;      if(fprintf(stream, "[]") < 0){
436      return;        perror("print_val");
437    }        env->err= 5;
438    typenum=env->head->item->type;        return;
439    toss(env);      }
   switch(typenum){  
   case integer:  
     push_sym(env, "integer");  
     break;  
   case string:  
     push_sym(env, "string");  
     break;  
   case symb:  
     push_sym(env, "symbol");  
     break;  
   case func:  
     push_sym(env, "function");  
     break;  
   case list:  
     push_sym(env, "list");  
440      break;      break;
   }  
 }      
   
 /* Prints the top element of the stack. */  
 void print_h(stackitem *stack_head, int noquote)  
 {  
   switch(stack_head->item->type) {  
441    case integer:    case integer:
442      printf("%d", stack_head->item->content.val);      if(fprintf(stream, "%d", val->content.i) < 0){
443          perror("print_val");
444          env->err= 5;
445          return;
446        }
447        break;
448      case tfloat:
449        if(fprintf(stream, "%f", val->content.f) < 0){
450          perror("print_val");
451          env->err= 5;
452          return;
453        }
454      break;      break;
455    case string:    case string:
456      if(noquote)      if(noquote){
457        printf("%s", (char*)stack_head->item->content.ptr);        if(fprintf(stream, "%s", (char*)(val->content.ptr)) < 0){
458      else          perror("print_val");
459        printf("\"%s\"", (char*)stack_head->item->content.ptr);          env->err= 5;
460            return;
461          }
462        } else {                    /* quote */
463          if(fprintf(stream, "\"%s\"", (char*)(val->content.ptr)) < 0){
464            perror("print_val");
465            env->err= 5;
466            return;
467          }
468        }
469      break;      break;
470    case symb:    case symb:
471      printf("%s", ((symbol *)(stack_head->item->content.ptr))->id);      if(fprintf(stream, "%s", val->content.sym->id) < 0){
472          perror("print_val");
473          env->err= 5;
474          return;
475        }
476      break;      break;
477    case func:    case func:
478      printf("#<function %p>", (funcp)(stack_head->item->content.ptr));      if(fprintf(stream, "#<function %p>", (funcp)(val->content.ptr)) < 0){
479          perror("print_val");
480          env->err= 5;
481          return;
482        }
483      break;      break;
484    case list:    case port:
485      /* A list is just a stack, so make stack_head point to it */      if(fprintf(stream, "#<port %p>", (funcp)(val->content.p)) < 0){
486      stack_head=(stackitem *)(stack_head->item->content.ptr);        perror("print_val");
487      printf("[ ");        env->err= 5;
488      while(stack_head != NULL) {        return;
       print_h(stack_head, noquote);  
       printf(" ");  
       stack_head=stack_head->next;  
489      }      }
     printf("]");  
490      break;      break;
491    }    case tcons:
492  }      if(fprintf(stream, "[ ") < 0){
493          perror("print_val");
494  extern void print_(environment *env) {        env->err= 5;
495    if(env->head==NULL) {        return;
496      printerr("Too Few Arguments");      }
497      env->err=1;      tstack= stack;
498      return;      do {
499    }        titem=malloc(sizeof(stackitem));
500    print_h(env->head, 0);        assert(titem != NULL);
501    nl();        titem->item=val;
502  }        titem->next=tstack;
503          tstack=titem;             /* Put it on the stack */
504  /* Prints the top element of the stack and then discards it. */        /* Search a stack of values being printed to see if we are already
505  extern void print(environment *env)           printing this value */
506  {        titem=tstack;
507    print_(env);        depth=0;
508    if(env->err) return;        while(titem != NULL && titem->item != CAR(val)){
509    toss(env);          titem=titem->next;
510  }          depth++;
511          }
512  extern void princ_(environment *env) {        if(titem != NULL){        /* If we found it on the stack, */
513    if(env->head==NULL) {          if(fprintf(stream, "#%d#", depth) < 0){ /* print a depth reference */
514      printerr("Too Few Arguments");            perror("print_val");
515      env->err=1;            env->err= 5;
516      return;            free(titem);
517    }            return;
518    print_h(env->head, 1);          }
519  }        } else {
520            print_val(env, CAR(val), noquote, tstack, stream);
521          }
522          val= CDR(val);
523          switch(val->type){
524          case empty:
525            break;
526          case tcons:
527            /* Search a stack of values being printed to see if we are already
528               printing this value */
529            titem=tstack;
530            depth=0;
531            while(titem != NULL && titem->item != val){
532              titem=titem->next;
533              depth++;
534            }
535            if(titem != NULL){      /* If we found it on the stack, */
536              if(fprintf(stream, " . #%d#", depth) < 0){ /* print a depth reference */
537                perror("print_val");
538                env->err= 5;
539                goto printval_end;
540              }
541            } else {
542              if(fprintf(stream, " ") < 0){
543                perror("print_val");
544                env->err= 5;
545                goto printval_end;
546              }
547            }
548            break;
549          default:
550            if(fprintf(stream, " . ") < 0){ /* Improper list */
551              perror("print_val");
552              env->err= 5;
553              goto printval_end;
554            }
555            print_val(env, val, noquote, tstack, stream);
556          }
557        } while(val->type == tcons && titem == NULL);
558    
559  /* Prints the top element of the stack and then discards it. */    printval_end:
 extern void princ(environment *env)  
 {  
   princ_(env);  
   if(env->err) return;  
   toss(env);  
 }  
560    
561  /* Only to be called by function printstack. */      titem=tstack;
562  void print_st(stackitem *stack_head, long counter)      while(titem != stack){
563  {        tstack=titem->next;
564    if(stack_head->next != NULL)        free(titem);
565      print_st(stack_head->next, counter+1);        titem=tstack;
566    printf("%ld: ", counter);      }
   print_h(stack_head, 0);  
   nl();  
 }  
567    
568  /* Prints the stack. */      if(! (env->err)){
569  extern void printstack(environment *env)        if(fprintf(stream, " ]") < 0){
570  {          perror("print_val");
571    if(env->head == NULL) {          env->err= 5;
572      printf("Stack Empty\n");        }
573      return;      }
574        break;
575    }    }
   print_st(env->head, 1);  
576  }  }
577    
578  /* Swap the two top elements on the stack. */  /* Swap the two top elements on the stack. */
579  extern void swap(environment *env)  extern void swap(environment *env)
580  {  {
581    stackitem *temp= env->head;    value *temp= env->head;
582        
583    if(env->head==NULL || env->head->next==NULL) {    if(env->head->type == empty || CDR(env->head)->type == empty) {
584      printerr("Too Few Arguments");      printerr("Too Few Arguments");
585      env->err=1;      env->err=1;
586      return;      return;
587    }    }
588    
589    env->head= env->head->next;    env->head= CDR(env->head);
590    temp->next= env->head->next;    CDR(temp)= CDR(env->head);
591    env->head->next= temp;    CDR(env->head)= temp;
592  }  }
593    
 /* Rotate the first three elements on the stack. */  
 extern void rot(environment *env)  
 {  
   stackitem *temp= env->head;  
     
   if(env->head==NULL || env->head->next==NULL  
       || env->head->next->next==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   env->head= env->head->next->next;  
   temp->next->next= env->head->next;  
   env->head->next= temp;  
 }  
   
594  /* Recall a value from a symbol, if bound */  /* Recall a value from a symbol, if bound */
595  extern void rcl(environment *env)  extern void rcl(environment *env)
596  {  {
597    value *val;    value *val;
598    
599    if(env->head == NULL) {    if(env->head->type==empty) {
600      printerr("Too Few Arguments");      printerr("Too Few Arguments");
601      env->err=1;      env->err= 1;
602      return;      return;
603    }    }
604    
605    if(env->head->item->type!=symb) {    if(CAR(env->head)->type!=symb) {
606      printerr("Bad Argument Type");      printerr("Bad Argument Type");
607      env->err=2;      env->err= 2;
608      return;      return;
609    }    }
610    
611    val=((symbol *)(env->head->item->content.ptr))->val;    val= CAR(env->head)->content.sym->val;
612    if(val == NULL){    if(val == NULL){
613      printerr("Unbound Variable");      printerr("Unbound Variable");
614      env->err=3;      env->err= 3;
615      return;      return;
616    }    }
617    toss(env);            /* toss the symbol */    push_val(env, val);           /* Return the symbol's bound value */
618      swap(env);
619      if(env->err) return;
620      toss(env);                    /* toss the symbol */
621    if(env->err) return;    if(env->err) return;
   push_val(env, val); /* Return its bound value */  
622  }  }
623    
624    
625  /* If the top element is a symbol, determine if it's bound to a  /* If the top element is a symbol, determine if it's bound to a
626     function value, and if it is, toss the symbol and execute the     function value, and if it is, toss the symbol and execute the
627     function. */     function. */
# Line 509  extern void eval(environment *env) Line 629  extern void eval(environment *env)
629  {  {
630    funcp in_func;    funcp in_func;
631    value* temp_val;    value* temp_val;
632    stackitem* iterator;    value* iterator;
633    
634   eval_start:   eval_start:
635    
636    if(env->head==NULL) {    gc_maybe(env);
637    
638      if(env->head->type==empty) {
639      printerr("Too Few Arguments");      printerr("Too Few Arguments");
640      env->err=1;      env->err= 1;
641      return;      return;
642    }    }
643    
644    switch(env->head->item->type) {    switch(CAR(env->head)->type) {
645      /* if it's a symbol */      /* if it's a symbol */
646    case symb:    case symb:
647      rcl(env);                   /* get its contents */      rcl(env);                   /* get its contents */
648      if(env->err) return;      if(env->err) return;
649      if(env->head->item->type!=symb){ /* don't recurse symbols */      if(CAR(env->head)->type!=symb){ /* don't recurse symbols */
650        goto eval_start;        goto eval_start;
651      }      }
652      return;      return;
653    
654      /* If it's a lone function value, run it */      /* If it's a lone function value, run it */
655    case func:    case func:
656      in_func= (funcp)(env->head->item->content.ptr);      in_func= (funcp)(CAR(env->head)->content.ptr);
657      toss(env);      toss(env);
658      if(env->err) return;      if(env->err) return;
659      return in_func(env);      return in_func(env);
660    
661      /* If it's a list */      /* If it's a list */
662    case list:    case tcons:
663      temp_val= env->head->item;      temp_val= CAR(env->head);
664      toss(env);      protect(temp_val);
665      if(env->err) return;  
666      iterator= (stackitem*)temp_val->content.ptr;      toss(env); if(env->err) return;
667      while(iterator!=NULL) {      iterator= temp_val;
668        push_val(env, iterator->item);      
669        if(env->head->item->type==symb      while(iterator->type != empty) {
670          && strcmp(";", ((symbol*)(env->head->item->content.ptr))->id)==0) {        push_val(env, CAR(iterator));
671          
672          if(CAR(env->head)->type==symb
673             && CAR(env->head)->content.sym->id[0]==';') {
674          toss(env);          toss(env);
675          if(env->err) return;          if(env->err) return;
676          if(iterator->next == NULL){          
677            if(CDR(iterator)->type == empty){
678            goto eval_start;            goto eval_start;
679          }          }
680          eval(env);          eval(env);
681          if(env->err) return;          if(env->err) return;
682        }        }
683        iterator= iterator->next;        if (CDR(iterator)->type == empty || CDR(iterator)->type == tcons)
684            iterator= CDR(iterator);
685          else {
686            printerr("Bad Argument Type"); /* Improper list */
687            env->err= 2;
688            return;
689          }
690      }      }
691        unprotect(temp_val);
692      return;      return;
693    
694    default:    case empty:
695      return;      toss(env);
696    }    case integer:
697  }    case tfloat:
698      case string:
699  /* Reverse (flip) a list */    case port:
 extern void rev(environment *env){  
   stackitem *old_head, *new_head, *item;  
   
   if((env->head)==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   if(env->head->item->type!=list) {  
     printerr("Bad Argument Type");  
     env->err=2;  
     return;  
   }  
   
   old_head=(stackitem *)(env->head->item->content.ptr);  
   new_head=NULL;  
   while(old_head != NULL){  
     item=old_head;  
     old_head=old_head->next;  
     item->next=new_head;  
     new_head=item;  
   }  
   env->head->item->content.ptr=new_head;  
 }  
   
 /* Make a list. */  
 extern void pack(environment *env)  
 {  
   stackitem *iterator, *temp;  
   value *pack;  
   
   iterator= env->head;  
   
   if(iterator==NULL  
      || (iterator->item->type==symb  
      && ((symbol*)(iterator->item->content.ptr))->id[0]=='[')) {  
     temp= NULL;  
     toss(env);  
   } else {  
     /* Search for first delimiter */  
     while(iterator->next!=NULL  
           && (iterator->next->item->type!=symb  
           || ((symbol*)(iterator->next->item->content.ptr))->id[0]!='['))  
       iterator= iterator->next;  
       
     /* Extract list */  
     temp= env->head;  
     env->head= iterator->next;  
     iterator->next= NULL;  
       
     if(env->head!=NULL)  
       toss(env);  
   }  
   
   /* Push list */  
   pack= new_val(env);  
   pack->type= list;  
   pack->content.ptr= temp;  
   
   push_val(env, pack);  
   rev(env);  
 }  
   
 /* Relocate elements of the list on the stack. */  
 extern void expand(environment *env)  
 {  
   stackitem *temp, *new_head;  
   
   /* Is top element a list? */  
   if(env->head==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   if(env->head->item->type!=list) {  
     printerr("Bad Argument Type");  
     env->err=2;  
700      return;      return;
701    }    }
   
   rev(env);  
   
   if(env->err)  
     return;  
   
   /* The first list element is the new stack head */  
   new_head= temp= env->head->item->content.ptr;  
   
   toss(env);  
   
   /* Find the end of the list */  
   while(temp->next!=NULL)  
     temp= temp->next;  
   
   /* Connect the tail of the list with the old stack head */  
   temp->next= env->head;  
   env->head= new_head;          /* ...and voila! */  
   
702  }  }
703    
704  /* Compares two elements by reference. */  /* List all defined words */
705  extern void eq(environment *env)  extern void words(environment *env)
706  {  {
707    void *left, *right;    symbol *temp;
708    int result;    int i;
   
   if((env->head)==NULL || env->head->next==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   left= env->head->item->content.ptr;  
   swap(env);  
   right= env->head->item->content.ptr;  
   result= (left==right);  
709        
710    toss(env); toss(env);    for(i= 0; i<HASHTBLSIZE; i++) {
711    push_int(env, result);      temp= env->symbols[i];
712  }      while(temp!=NULL) {
713    #ifdef DEBUG
714  /* Negates the top element on the stack. */        if (temp->val != NULL && temp->val->gc.flag.protect)
715  extern void not(environment *env)          printf("(protected) ");
716  {  #endif /* DEBUG */
717    int val;        printf("%s ", temp->id);
718          temp= temp->next;
719    if((env->head)==NULL) {      }
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   if(env->head->item->type!=integer) {  
     printerr("Bad Argument Type");  
     env->err=2;  
     return;  
720    }    }
   
   val= env->head->item->content.val;  
   toss(env);  
   push_int(env, !val);  
721  }  }
722    
 /* Compares the two top elements on the stack and return 0 if they're the  
    same. */  
 extern void neq(environment *env)  
 {  
   eq(env);  
   not(env);  
 }  
   
 /* Give a symbol some content. */  
 extern void def(environment *env)  
 {  
   symbol *sym;  
   
   /* Needs two values on the stack, the top one must be a symbol */  
   if(env->head==NULL || env->head->next==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   if(env->head->item->type!=symb) {  
     printerr("Bad Argument Type");  
     env->err=2;  
     return;  
   }  
   
   /* long names are a pain */  
   sym=env->head->item->content.ptr;  
   
   /* if the symbol was bound to something else, throw it away */  
   
   /* Bind the symbol to the value */  
   sym->val= env->head->next->item;  
   
   toss(env); toss(env);  
 }  
   
723  /* Quit stack. */  /* Quit stack. */
724  extern void quit(environment *env)  extern void quit(environment *env)
725  {  {
726    long i;    int i;
727    
728    clear(env);    while(env->head->type != empty)
729        toss(env);
730    
731    if (env->err) return;    if (env->err) return;
732    for(i= 0; i<HASHTBLSIZE; i++) {    for(i= 0; i<HASHTBLSIZE; i++) {
# Line 760  extern void quit(environment *env) Line 736  extern void quit(environment *env)
736      env->symbols[i]= NULL;      env->symbols[i]= NULL;
737    }    }
738    
739    gc_init(env);    env->gc_limit= 0;
740      gc_maybe(env);
741    
742      words(env);
743    
744    if(env->free_string!=NULL)    if(env->free_string!=NULL)
745      free(env->free_string);      free(env->free_string);
746        
747    #ifdef __linux__
748    muntrace();    muntrace();
749    #endif
750    
751    exit(EXIT_SUCCESS);    exit(EXIT_SUCCESS);
752  }  }
753    
 /* Clear stack */  
 extern void clear(environment *env)  
 {  
   while(env->head!=NULL)  
     toss(env);  
 }  
   
 /* List all defined words */  
 extern void words(environment *env)  
 {  
   symbol *temp;  
   int i;  
     
   for(i= 0; i<HASHTBLSIZE; i++) {  
     temp= env->symbols[i];  
     while(temp!=NULL) {  
       printf("%s\n", temp->id);  
       temp= temp->next;  
     }  
   }  
 }  
   
754  /* Internal forget function */  /* Internal forget function */
755  void forget_sym(symbol **hash_entry) {  void forget_sym(symbol **hash_entry)
756    {
757    symbol *temp;    symbol *temp;
758    
759    temp= *hash_entry;    temp= *hash_entry;
# Line 803  void forget_sym(symbol **hash_entry) { Line 763  void forget_sym(symbol **hash_entry) {
763    free(temp);    free(temp);
764  }  }
765    
766  /* Forgets a symbol (remove it from the hash table) */  /* Only to be called by itself function printstack. */
767  extern void forget(environment *env)  void print_st(environment *env, value *stack_head, long counter)
768  {  {
769    char* sym_id;    if(CDR(stack_head)->type != empty)
770    stackitem *stack_head= env->head;      print_st(env, CDR(stack_head), counter+1);
771      printf("%ld: ", counter);
772      print_val(env, CAR(stack_head), 0, NULL, stdout);
773      printf("\n");
774    }
775    
776    if(stack_head==NULL) {  /* Prints the stack. */
777      printerr("Too Few Arguments");  extern void printstack(environment *env)
778      env->err=1;  {
779      return;    if(env->head->type == empty) {
780    }      printf("Stack Empty\n");
     
   if(stack_head->item->type!=symb) {  
     printerr("Bad Argument Type");  
     env->err=2;  
781      return;      return;
782    }    }
783    
784    sym_id= ((symbol*)(stack_head->item->content.ptr))->id;    print_st(env, env->head, 1);
   toss(env);  
   
   return forget_sym(hash(env->symbols, sym_id));  
 }  
   
 /* Returns the current error number to the stack */  
 extern void errn(environment *env){  
   push_int(env, env->err);  
785  }  }
786    
787  int main(int argc, char **argv)  int main(int argc, char **argv)
# Line 838  int main(int argc, char **argv) Line 790  int main(int argc, char **argv)
790    
791    int c;                        /* getopt option character */    int c;                        /* getopt option character */
792    
793    #ifdef __linux__
794    mtrace();    mtrace();
795    #endif
796    
797    init_env(&myenv);    init_env(&myenv);
798    
# Line 852  int main(int argc, char **argv) Line 806  int main(int argc, char **argv)
806          break;          break;
807        case '?':        case '?':
808          fprintf (stderr,          fprintf (stderr,
809                   "Unknown option character `\\x%x'.\n",                   "Unknown option character '\\x%x'.\n",
810                   optopt);                   optopt);
811          return EX_USAGE;          return EX_USAGE;
812        default:        default:
# Line 868  int main(int argc, char **argv) Line 822  int main(int argc, char **argv)
822      }      }
823    }    }
824    
825      if(myenv.interactive) {
826        printf("Stack version $Revision$\n\
827    Copyright (C) 2002  Mats Alritzson and Teddy Hogeborn\n\
828    Stack comes with ABSOLUTELY NO WARRANTY; for details type 'warranty;'.\n\
829    This is free software, and you are welcome to redistribute it\n\
830    under certain conditions; type 'copying;' for details.\n");
831      }
832    
833    while(1) {    while(1) {
834      if(myenv.in_string==NULL) {      if(myenv.in_string==NULL) {
835        if (myenv.interactive) {        if (myenv.interactive) {
836          if(myenv.err) {          if(myenv.err) {
837            printf("(error %d)\n", myenv.err);            printf("(error %d)\n", myenv.err);
838              myenv.err= 0;
839          }          }
840          nl();          printf("\n");
841          printstack(&myenv);          printstack(&myenv);
842          printf("> ");          printf("> ");
843        }        }
844        myenv.err=0;        myenv.err=0;
845      }      }
846      sx_72656164(&myenv);      readstream(&myenv, myenv.inputstream);
847      if (myenv.err==4) {      if (myenv.err) {            /* EOF or other error */
848        return EX_NOINPUT;        myenv.err=0;
849      } else if(myenv.head!=NULL        quit(&myenv);
850                && myenv.head->item->type==symb      } else if(myenv.head->type!=empty
851                && ((symbol*)(myenv.head->item->content.ptr))->id[0]==';') {                && CAR(myenv.head)->type==symb
852        toss(&myenv);             /* No error check in main */                && CAR(myenv.head)->content.sym->id[0] == ';') {
853          toss(&myenv); if(myenv.err) continue;
854        eval(&myenv);        eval(&myenv);
855        } else {
856          gc_maybe(&myenv);
857      }      }
     gc_init(&myenv);  
858    }    }
859    quit(&myenv);    quit(&myenv);
860    return EXIT_FAILURE;    return EXIT_FAILURE;
861  }  }
862    
 /* "+" */  
 extern void sx_2b(environment *env) {  
   int a, b;  
   size_t len;  
   char* new_string;  
   value *a_val, *b_val;  
   
   if((env->head)==NULL || env->head->next==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   if(env->head->item->type==string  
      && env->head->next->item->type==string) {  
     a_val= env->head->item;  
     b_val= env->head->next->item;  
     toss(env); if(env->err) return;  
     toss(env); if(env->err) return;  
     len= strlen(a_val->content.ptr)+strlen(b_val->content.ptr)+1;  
     new_string= malloc(len);  
     strcpy(new_string, b_val->content.ptr);  
     strcat(new_string, a_val->content.ptr);  
     push_cstring(env, new_string);  
     free(new_string);  
     return;  
   }  
     
   if(env->head->item->type!=integer  
      || env->head->next->item->type!=integer) {  
     printerr("Bad Argument Type");  
     env->err=2;  
     return;  
   }  
   a=env->head->item->content.val;  
   toss(env); if(env->err) return;  
     
   b=env->head->item->content.val;  
   toss(env); if(env->err) return;  
   push_int(env, a+b);  
 }  
   
 /* "-" */  
 extern void sx_2d(environment *env) {  
   int a, b;  
   
   if((env->head)==NULL || env->head->next==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
     
   if(env->head->item->type!=integer  
      || env->head->next->item->type!=integer) {  
     printerr("Bad Argument Type");  
     env->err=2;  
     return;  
   }  
   a=env->head->item->content.val;  
   toss(env); if(env->err) return;  
   b=env->head->item->content.val;  
   toss(env); if(env->err) return;  
   push_int(env, b-a);  
 }  
   
 /* ">" */  
 extern void sx_3e(environment *env) {  
   int a, b;  
   
   if((env->head)==NULL || env->head->next==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
     
   if(env->head->item->type!=integer  
      || env->head->next->item->type!=integer) {  
     printerr("Bad Argument Type");  
     env->err=2;  
     return;  
   }  
   a=env->head->item->content.val;  
   toss(env); if(env->err) return;  
   b=env->head->item->content.val;  
   toss(env); if(env->err) return;  
   push_int(env, b>a);  
 }  
   
863  /* Return copy of a value */  /* Return copy of a value */
864  value *copy_val(environment *env, value *old_value){  value *copy_val(environment *env, value *old_value)
865    stackitem *old_item, *new_item, *prev_item;  {
866      value *new_value;
867    
868    value *new_value=new_val(env);    if(old_value==NULL)
869        return NULL;
870    
871    new_value->type=old_value->type;    new_value= new_val(env);
872      new_value->type= old_value->type;
873    
874    switch(old_value->type){    switch(old_value->type){
875      case tfloat:
876    case integer:    case integer:
     new_value->content.val=old_value->content.val;  
     break;  
   case string:  
     (char *)(new_value->content.ptr)  
       = strdup((char *)(old_value->content.ptr));  
     break;  
877    case func:    case func:
878    case symb:    case symb:
879      new_value->content.ptr=old_value->content.ptr;    case empty:
880      case port:
881        new_value->content= old_value->content;
882      break;      break;
883    case list:    case string:
884      new_value->content.ptr=NULL;      (char *)(new_value->content.ptr)=
885          strdup((char *)(old_value->content.ptr));
     prev_item=NULL;  
     old_item=(stackitem *)(old_value->content.ptr);  
   
     while(old_item != NULL) {   /* While list is not empty */  
       new_item= malloc(sizeof(stackitem));  
       new_item->item=copy_val(env, old_item->item); /* recurse */  
       new_item->next=NULL;  
       if(prev_item != NULL)     /* If this wasn't the first item */  
         prev_item->next=new_item; /* point the previous item to the  
                                      new item */  
       else  
         new_value->content.ptr=new_item;  
       old_item=old_item->next;  
       prev_item=new_item;  
     }      
886      break;      break;
887    }    case tcons:
   return new_value;  
 }  
   
 /* "dup"; duplicates an item on the stack */  
 extern void sx_647570(environment *env) {  
   if((env->head)==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   push_val(env, copy_val(env, env->head->item));  
 }  
888    
889  /* "if", If-Then */      new_value->content.c= malloc(sizeof(pair));
890  extern void sx_6966(environment *env) {      assert(new_value->content.c!=NULL);
891        env->gc_count += sizeof(pair);
892    
893    int truth;      CAR(new_value)= copy_val(env, CAR(old_value)); /* recurse */
894        CDR(new_value)= copy_val(env, CDR(old_value)); /* recurse */
895    if((env->head)==NULL || env->head->next==NULL) {      break;
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   if(env->head->next->item->type != integer) {  
     printerr("Bad Argument Type");  
     env->err=2;  
     return;  
   }  
     
   swap(env);  
   if(env->err) return;  
     
   truth=env->head->item->content.val;  
   
   toss(env);  
   if(env->err) return;  
   
   if(truth)  
     eval(env);  
   else  
     toss(env);  
 }  
   
 /* If-Then-Else */  
 extern void ifelse(environment *env) {  
   
   int truth;  
   
   if((env->head)==NULL || env->head->next==NULL  
      || env->head->next->next==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   if(env->head->next->next->item->type != integer) {  
     printerr("Bad Argument Type");  
     env->err=2;  
     return;  
896    }    }
     
   rot(env);  
   if(env->err) return;  
     
   truth=env->head->item->content.val;  
   
   toss(env);  
   if(env->err) return;  
897    
898    if(!truth)    return new_value;
     swap(env);  
   if(env->err) return;  
   
   toss(env);  
   if(env->err) return;  
   
   eval(env);  
899  }  }
900    
901  /* "while" */  /* read a line from a stream; used by readline */
902  extern void sx_7768696c65(environment *env) {  void readlinestream(environment *env, FILE *stream)
903    {
904    int truth;    char in_string[101];
   value *loop, *test;  
   
   if((env->head)==NULL || env->head->next==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   loop= env->head->item;  
   toss(env); if(env->err) return;  
   
   test= env->head->item;  
   toss(env); if(env->err) return;  
905    
906    do {    if(fgets(in_string, 100, stream)==NULL) {
907      push_val(env, test);      push_cstring(env, "");
908      eval(env);      if (! feof(stream)){
909              perror("readline");
910      if(env->head->item->type != integer) {        env->err= 5;
       printerr("Bad Argument Type");  
       env->err=2;  
       return;  
     }  
       
     truth= env->head->item->content.val;  
     toss(env); if(env->err) return;  
       
     if(truth) {  
       push_val(env, loop);  
       eval(env);  
     } else {  
       toss(env);  
911      }      }
912        } else {
913    } while(truth);      push_cstring(env, in_string);
914      }
915  }  }
916    
917    /* Reverse (flip) a list */
918    extern void rev(environment *env)
919    {
920      value *old_head, *new_head, *item;
921    
922  /* "for"; for-loop */    if(env->head->type==empty) {
 extern void sx_666f72(environment *env) {  
   value *loop;  
   int foo1, foo2;  
   
   if(env->head==NULL || env->head->next==NULL  
      || env->head->next->next==NULL) {  
923      printerr("Too Few Arguments");      printerr("Too Few Arguments");
924      env->err= 1;      env->err= 1;
925      return;      return;
926    }    }
927    
928    if(env->head->next->item->type!=integer    if(CAR(env->head)->type==empty)
929       || env->head->next->next->item->type!=integer) {      return;                     /* Don't reverse an empty list */
     printerr("Bad Argument Type");  
     env->err= 2;  
     return;  
   }  
   
   loop= env->head->item;  
   toss(env); if(env->err) return;  
   
   foo2= env->head->item->content.val;  
   toss(env); if(env->err) return;  
930    
931    foo1= env->head->item->content.val;    if(CAR(env->head)->type!=tcons) {
   toss(env); if(env->err) return;  
   
   if(foo1<=foo2) {  
     while(foo1<=foo2) {  
       push_int(env, foo1);  
       push_val(env, loop);  
       eval(env); if(env->err) return;  
       foo1++;  
     }  
   } else {  
     while(foo1>=foo2) {  
       push_int(env, foo1);  
       push_val(env, loop);  
       eval(env); if(env->err) return;  
       foo1--;  
     }  
   }  
 }  
   
 /* Variant of for-loop */  
 extern void foreach(environment *env) {  
     
   value *loop, *foo;  
   stackitem *iterator;  
     
   if((env->head)==NULL || env->head->next==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   if(env->head->next->item->type != list) {  
932      printerr("Bad Argument Type");      printerr("Bad Argument Type");
933      env->err=2;      env->err= 2;
934      return;      return;
935    }    }
936    
937    loop= env->head->item;    old_head= CAR(env->head);
938    toss(env); if(env->err) return;    new_head= new_val(env);
939      while(old_head->type != empty) {
940    foo= env->head->item;      item= old_head;
941    toss(env); if(env->err) return;      old_head= CDR(old_head);
942        CDR(item)= new_head;
943    iterator= foo->content.ptr;      new_head= item;
   
   while(iterator!=NULL) {  
     push_val(env, iterator->item);  
     push_val(env, loop);  
     eval(env); if(env->err) return;  
     iterator= iterator->next;  
944    }    }
945      CAR(env->head)= new_head;
946  }  }
947    
948  /* "to" */  /* Make a list. */
949  extern void to(environment *env) {  extern void pack(environment *env)
950    int i, start, ending;  {
951    stackitem *temp_head;    value *iterator, *temp, *ending;
   value *temp_val;  
     
   if((env->head)==NULL || env->head->next==NULL) {  
     printerr("Too Few Arguments");  
     env->err=1;  
     return;  
   }  
   
   if(env->head->item->type!=integer  
      || env->head->next->item->type!=integer) {  
     printerr("Bad Argument Type");  
     env->err=2;  
     return;  
   }  
   
   ending= env->head->item->content.val;  
   toss(env); if(env->err) return;  
   start= env->head->item->content.val;  
   toss(env); if(env->err) return;  
952    
953    temp_head= env->head;    ending=new_val(env);
   env->head= NULL;  
954    
955    if(ending>=start) {    iterator= env->head;
956      for(i= ending; i>=start; i--)    if(iterator->type == empty
957        push_int(env, i);       || (CAR(iterator)->type==symb
958         && CAR(iterator)->content.sym->id[0]=='[')) {
959        temp= ending;
960        toss(env);
961    } else {    } else {
962      for(i= ending; i<=start; i++)      /* Search for first delimiter */
963        push_int(env, i);      while(CDR(iterator)->type != empty
964    }            && (CAR(CDR(iterator))->type!=symb
965               || CAR(CDR(iterator))->content.sym->id[0]!='['))
966          iterator= CDR(iterator);
967        
968        /* Extract list */
969        temp= env->head;
970        env->head= CDR(iterator);
971        CDR(iterator)= ending;
972    
973    temp_val= new_val(env);      if(env->head->type != empty)
974    temp_val->content.ptr= env->head;        toss(env);
975    temp_val->type= list;    }
   env->head= temp_head;  
   push_val(env, temp_val);  
 }  
976    
977  /* Read a string */    /* Push list */
 extern void readline(environment *env) {  
   char in_string[101];  
978    
979    if(fgets(in_string, 100, env->inputstream)==NULL)    push_val(env, temp);
980      push_cstring(env, "");    rev(env);
   else  
     push_cstring(env, in_string);  
981  }  }
982    
983  /* "read"; Read a value and place on stack */  /* read from a stream; used by "read" and "readport" */
984  extern void sx_72656164(environment *env) {  void readstream(environment *env, FILE *stream)
985    {
986    const char symbform[]= "%[a-zA-Z0-9!$%*+./:<=>?@^_~-]%n";    const char symbform[]= "%[a-zA-Z0-9!$%*+./:<=>?@^_~-]%n";
987    const char strform[]= "\"%[^\"]\"%n";    const char strform[]= "\"%[^\"]\"%n";
988    const char intform[]= "%i%n";    const char intform[]= "%i%n";
989      const char fltform[]= "%f%n";
990    const char blankform[]= "%*[ \t]%n";    const char blankform[]= "%*[ \t]%n";
991    const char ebrackform[]= "%*1[]]%n";    const char ebrackform[]= "]%n";
992    const char semicform[]= "%*1[;]%n";    const char semicform[]= ";%n";
993    const char bbrackform[]= "%*1[[]%n";    const char bbrackform[]= "[%n";
994    
995    int itemp, readlength= -1;    int itemp, readlength= -1;
996      int count= -1;
997      float ftemp;
998    static int depth= 0;    static int depth= 0;
999    char *match;    char *match;
1000    size_t inlength;    size_t inlength;
# Line 1295  extern void sx_72656164(environment *env Line 1003  extern void sx_72656164(environment *env
1003      if(depth > 0 && env->interactive) {      if(depth > 0 && env->interactive) {
1004        printf("]> ");        printf("]> ");
1005      }      }
1006      readline(env); if(env->err) return;      readlinestream(env, env->inputstream);
1007        if(env->err) return;
1008    
1009      if(((char *)(env->head->item->content.ptr))[0]=='\0'){      if(((char *)(CAR(env->head)->content.ptr))[0]=='\0'){
1010        env->err= 4;              /* "" means EOF */        env->err= 4;              /* "" means EOF */
1011        return;        return;
1012      }      }
1013            
1014      env->in_string= malloc(strlen(env->head->item->content.ptr)+1);      env->in_string= malloc(strlen(CAR(env->head)->content.ptr)+1);
1015        assert(env->in_string != NULL);
1016      env->free_string= env->in_string; /* Save the original pointer */      env->free_string= env->in_string; /* Save the original pointer */
1017      strcpy(env->in_string, env->head->item->content.ptr);      strcpy(env->in_string, CAR(env->head)->content.ptr);
1018      toss(env); if(env->err) return;      toss(env); if(env->err) return;
1019    }    }
1020        
1021    inlength= strlen(env->in_string)+1;    inlength= strlen(env->in_string)+1;
1022    match= malloc(inlength);    match= malloc(inlength);
1023      assert(match != NULL);
1024    
1025    if(sscanf(env->in_string, blankform, &readlength)!=EOF    if(sscanf(env->in_string, blankform, &readlength) != EOF
1026       && readlength != -1) {       && readlength != -1) {
1027      ;      ;
1028    } else if(sscanf(env->in_string, intform, &itemp, &readlength) != EOF    } else if(sscanf(env->in_string, fltform, &ftemp, &readlength) != EOF
1029              && readlength != -1) {              && readlength != -1) {
1030      push_int(env, itemp);      if(sscanf(env->in_string, intform, &itemp, &count) != EOF
1031           && count==readlength) {
1032          push_int(env, itemp);
1033        } else {
1034          push_float(env, ftemp);
1035        }
1036      } else if(sscanf(env->in_string, "\"\"%n", &readlength) != EOF
1037                && readlength != -1) {
1038        push_cstring(env, "");
1039    } else if(sscanf(env->in_string, strform, match, &readlength) != EOF    } else if(sscanf(env->in_string, strform, match, &readlength) != EOF
1040              && readlength != -1) {              && readlength != -1) {
1041      push_cstring(env, match);      push_cstring(env, match);
# Line 1338  extern void sx_72656164(environment *env Line 1057  extern void sx_72656164(environment *env
1057      free(env->free_string);      free(env->free_string);
1058      env->in_string = env->free_string = NULL;      env->in_string = env->free_string = NULL;
1059    }    }
1060    if ( env->in_string != NULL) {    if (env->in_string != NULL) {
1061      env->in_string += readlength;      env->in_string += readlength;
1062    }    }
1063    
1064    free(match);    free(match);
1065    
1066    if(depth)    if(depth)
1067      return sx_72656164(env);      return readstream(env, env->inputstream);
1068    }
1069    
1070    extern void copying(environment *env)
1071    {
1072      printf("                  GNU GENERAL PUBLIC LICENSE\n\
1073                           Version 2, June 1991\n\
1074    \n\
1075     Copyright (C) 1989, 1991 Free Software Foundation, Inc.\n\
1076         59 Temple Place, Suite 330, Boston, MA  02111-1307  USA\n\
1077     Everyone is permitted to copy and distribute verbatim copies\n\
1078     of this license document, but changing it is not allowed.\n\
1079    \n\
1080                                Preamble\n\
1081    \n\
1082      The licenses for most software are designed to take away your\n\
1083    freedom to share and change it.  By contrast, the GNU General Public\n\
1084    License is intended to guarantee your freedom to share and change free\n\
1085    software--to make sure the software is free for all its users.  This\n\
1086    General Public License applies to most of the Free Software\n\
1087    Foundation's software and to any other program whose authors commit to\n\
1088    using it.  (Some other Free Software Foundation software is covered by\n\
1089    the GNU Library General Public License instead.)  You can apply it to\n\
1090    your programs, too.\n\
1091    \n\
1092      When we speak of free software, we are referring to freedom, not\n\
1093    price.  Our General Public Licenses are designed to make sure that you\n\
1094    have the freedom to distribute copies of free software (and charge for\n\
1095    this service if you wish), that you receive source code or can get it\n\
1096    if you want it, that you can change the software or use pieces of it\n\
1097    in new free programs; and that you know you can do these things.\n\
1098    \n\
1099      To protect your rights, we need to make restrictions that forbid\n\
1100    anyone to deny you these rights or to ask you to surrender the rights.\n\
1101    These restrictions translate to certain responsibilities for you if you\n\
1102    distribute copies of the software, or if you modify it.\n\
1103    \n\
1104      For example, if you distribute copies of such a program, whether\n\
1105    gratis or for a fee, you must give the recipients all the rights that\n\
1106    you have.  You must make sure that they, too, receive or can get the\n\
1107    source code.  And you must show them these terms so they know their\n\
1108    rights.\n\
1109    \n\
1110      We protect your rights with two steps: (1) copyright the software, and\n\
1111    (2) offer you this license which gives you legal permission to copy,\n\
1112    distribute and/or modify the software.\n\
1113    \n\
1114      Also, for each author's protection and ours, we want to make certain\n\
1115    that everyone understands that there is no warranty for this free\n\
1116    software.  If the software is modified by someone else and passed on, we\n\
1117    want its recipients to know that what they have is not the original, so\n\
1118    that any problems introduced by others will not reflect on the original\n\
1119    authors' reputations.\n\
1120    \n\
1121      Finally, any free program is threatened constantly by software\n\
1122    patents.  We wish to avoid the danger that redistributors of a free\n\
1123    program will individually obtain patent licenses, in effect making the\n\
1124    program proprietary.  To prevent this, we have made it clear that any\n\
1125    patent must be licensed for everyone's free use or not licensed at all.\n\
1126    \n\
1127      The precise terms and conditions for copying, distribution and\n\
1128    modification follow.\n\
1129    \n\
1130                        GNU GENERAL PUBLIC LICENSE\n\
1131       TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION\n\
1132    \n\
1133      0. This License applies to any program or other work which contains\n\
1134    a notice placed by the copyright holder saying it may be distributed\n\
1135    under the terms of this General Public License.  The \"Program\", below,\n\
1136    refers to any such program or work, and a \"work based on the Program\"\n\
1137    means either the Program or any derivative work under copyright law:\n\
1138    that is to say, a work containing the Program or a portion of it,\n\
1139    either verbatim or with modifications and/or translated into another\n\
1140    language.  (Hereinafter, translation is included without limitation in\n\
1141    the term \"modification\".)  Each licensee is addressed as \"you\".\n\
1142    \n\
1143    Activities other than copying, distribution and modification are not\n\
1144    covered by this License; they are outside its scope.  The act of\n\
1145    running the Program is not restricted, and the output from the Program\n\
1146    is covered only if its contents constitute a work based on the\n\
1147    Program (independent of having been made by running the Program).\n\
1148    Whether that is true depends on what the Program does.\n\
1149    \n\
1150      1. You may copy and distribute verbatim copies of the Program's\n\
1151    source code as you receive it, in any medium, provided that you\n\
1152    conspicuously and appropriately publish on each copy an appropriate\n\
1153    copyright notice and disclaimer of warranty; keep intact all the\n\
1154    notices that refer to this License and to the absence of any warranty;\n\
1155    and give any other recipients of the Program a copy of this License\n\
1156    along with the Program.\n\
1157    \n\
1158    You may charge a fee for the physical act of transferring a copy, and\n\
1159    you may at your option offer warranty protection in exchange for a fee.\n\
1160    \n\
1161      2. You may modify your copy or copies of the Program or any portion\n\
1162    of it, thus forming a work based on the Program, and copy and\n\
1163    distribute such modifications or work under the terms of Section 1\n\
1164    above, provided that you also meet all of these conditions:\n\
1165    \n\
1166        a) You must cause the modified files to carry prominent notices\n\
1167        stating that you changed the files and the date of any change.\n\
1168    \n\
1169        b) You must cause any work that you distribute or publish, that in\n\
1170        whole or in part contains or is derived from the Program or any\n\
1171        part thereof, to be licensed as a whole at no charge to all third\n\
1172        parties under the terms of this License.\n\
1173    \n\
1174        c) If the modified program normally reads commands interactively\n\
1175        when run, you must cause it, when started running for such\n\
1176        interactive use in the most ordinary way, to print or display an\n\
1177        announcement including an appropriate copyright notice and a\n\
1178        notice that there is no warranty (or else, saying that you provide\n\
1179        a warranty) and that users may redistribute the program under\n\
1180        these conditions, and telling the user how to view a copy of this\n\
1181        License.  (Exception: if the Program itself is interactive but\n\
1182        does not normally print such an announcement, your work based on\n\
1183        the Program is not required to print an announcement.)\n\
1184    \n\
1185    These requirements apply to the modified work as a whole.  If\n\
1186    identifiable sections of that work are not derived from the Program,\n\
1187    and can be reasonably considered independent and separate works in\n\
1188    themselves, then this License, and its terms, do not apply to those\n\
1189    sections when you distribute them as separate works.  But when you\n\
1190    distribute the same sections as part of a whole which is a work based\n\
1191    on the Program, the distribution of the whole must be on the terms of\n\
1192    this License, whose permissions for other licensees extend to the\n\
1193    entire whole, and thus to each and every part regardless of who wrote it.\n\
1194    \n\
1195    Thus, it is not the intent of this section to claim rights or contest\n\
1196    your rights to work written entirely by you; rather, the intent is to\n\
1197    exercise the right to control the distribution of derivative or\n\
1198    collective works based on the Program.\n\
1199    \n\
1200    In addition, mere aggregation of another work not based on the Program\n\
1201    with the Program (or with a work based on the Program) on a volume of\n\
1202    a storage or distribution medium does not bring the other work under\n\
1203    the scope of this License.\n\
1204    \n\
1205      3. You may copy and distribute the Program (or a work based on it,\n\
1206    under Section 2) in object code or executable form under the terms of\n\
1207    Sections 1 and 2 above provided that you also do one of the following:\n\
1208    \n\
1209        a) Accompany it with the complete corresponding machine-readable\n\
1210        source code, which must be distributed under the terms of Sections\n\
1211        1 and 2 above on a medium customarily used for software interchange; or,\n\
1212    \n\
1213        b) Accompany it with a written offer, valid for at least three\n\
1214        years, to give any third party, for a charge no more than your\n\
1215        cost of physically performing source distribution, a complete\n\
1216        machine-readable copy of the corresponding source code, to be\n\
1217        distributed under the terms of Sections 1 and 2 above on a medium\n\
1218        customarily used for software interchange; or,\n\
1219    \n\
1220        c) Accompany it with the information you received as to the offer\n\
1221        to distribute corresponding source code.  (This alternative is\n\
1222        allowed only for noncommercial distribution and only if you\n\
1223        received the program in object code or executable form with such\n\
1224        an offer, in accord with Subsection b above.)\n\
1225    \n\
1226    The source code for a work means the preferred form of the work for\n\
1227    making modifications to it.  For an executable work, complete source\n\
1228    code means all the source code for all modules it contains, plus any\n\
1229    associated interface definition files, plus the scripts used to\n\
1230    control compilation and installation of the executable.  However, as a\n\
1231    special exception, the source code distributed need not include\n\
1232    anything that is normally distributed (in either source or binary\n\
1233    form) with the major components (compiler, kernel, and so on) of the\n\
1234    operating system on which the executable runs, unless that component\n\
1235    itself accompanies the executable.\n\
1236    \n\
1237    If distribution of executable or object code is made by offering\n\
1238    access to copy from a designated place, then offering equivalent\n\
1239    access to copy the source code from the same place counts as\n\
1240    distribution of the source code, even though third parties are not\n\
1241    compelled to copy the source along with the object code.\n\
1242    \n\
1243      4. You may not copy, modify, sublicense, or distribute the Program\n\
1244    except as expressly provided under this License.  Any attempt\n\
1245    otherwise to copy, modify, sublicense or distribute the Program is\n\
1246    void, and will automatically terminate your rights under this License.\n\
1247    However, parties who have received copies, or rights, from you under\n\
1248    this License will not have their licenses terminated so long as such\n\
1249    parties remain in full compliance.\n\
1250    \n\
1251      5. You are not required to accept this License, since you have not\n\
1252    signed it.  However, nothing else grants you permission to modify or\n\
1253    distribute the Program or its derivative works.  These actions are\n\
1254    prohibited by law if you do not accept this License.  Therefore, by\n\
1255    modifying or distributing the Program (or any work based on the\n\
1256    Program), you indicate your acceptance of this License to do so, and\n\
1257    all its terms and conditions for copying, distributing or modifying\n\
1258    the Program or works based on it.\n\
1259    \n\
1260      6. Each time you redistribute the Program (or any work based on the\n\
1261    Program), the recipient automatically receives a license from the\n\
1262    original licensor to copy, distribute or modify the Program subject to\n\
1263    these terms and conditions.  You may not impose any further\n\
1264    restrictions on the recipients' exercise of the rights granted herein.\n\
1265    You are not responsible for enforcing compliance by third parties to\n\
1266    this License.\n\
1267    \n\
1268      7. If, as a consequence of a court judgment or allegation of patent\n\
1269    infringement or for any other reason (not limited to patent issues),\n\
1270    conditions are imposed on you (whether by court order, agreement or\n\
1271    otherwise) that contradict the conditions of this License, they do not\n\
1272    excuse you from the conditions of this License.  If you cannot\n\
1273    distribute so as to satisfy simultaneously your obligations under this\n\
1274    License and any other pertinent obligations, then as a consequence you\n\
1275    may not distribute the Program at all.  For example, if a patent\n\
1276    license would not permit royalty-free redistribution of the Program by\n\
1277    all those who receive copies directly or indirectly through you, then\n\
1278    the only way you could satisfy both it and this License would be to\n\
1279    refrain entirely from distribution of the Program.\n\
1280    \n\
1281    If any portion of this section is held invalid or unenforceable under\n\
1282    any particular circumstance, the balance of the section is intended to\n\
1283    apply and the section as a whole is intended to apply in other\n\
1284    circumstances.\n\
1285    \n\
1286    It is not the purpose of this section to induce you to infringe any\n\
1287    patents or other property right claims or to contest validity of any\n\
1288    such claims; this section has the sole purpose of protecting the\n\
1289    integrity of the free software distribution system, which is\n\
1290    implemented by public license practices.  Many people have made\n\
1291    generous contributions to the wide range of software distributed\n\
1292    through that system in reliance on consistent application of that\n\
1293    system; it is up to the author/donor to decide if he or she is willing\n\
1294    to distribute software through any other system and a licensee cannot\n\
1295    impose that choice.\n\
1296    \n\
1297    This section is intended to make thoroughly clear what is believed to\n\
1298    be a consequence of the rest of this License.\n\
1299    \n\
1300      8. If the distribution and/or use of the Program is restricted in\n\
1301    certain countries either by patents or by copyrighted interfaces, the\n\
1302    original copyright holder who places the Program under this License\n\
1303    may add an explicit geographical distribution limitation excluding\n\
1304    those countries, so that distribution is permitted only in or among\n\
1305    countries not thus excluded.  In such case, this License incorporates\n\
1306    the limitation as if written in the body of this License.\n\
1307    \n\
1308      9. The Free Software Foundation may publish revised and/or new versions\n\
1309    of the General Public License from time to time.  Such new versions will\n\
1310    be similar in spirit to the present version, but may differ in detail to\n\
1311    address new problems or concerns.\n\
1312    \n\
1313    Each version is given a distinguishing version number.  If the Program\n\
1314    specifies a version number of this License which applies to it and \"any\n\
1315    later version\", you have the option of following the terms and conditions\n\
1316    either of that version or of any later version published by the Free\n\
1317    Software Foundation.  If the Program does not specify a version number of\n\
1318    this License, you may choose any version ever published by the Free Software\n\
1319    Foundation.\n\
1320    \n\
1321      10. If you wish to incorporate parts of the Program into other free\n\
1322    programs whose distribution conditions are different, write to the author\n\
1323    to ask for permission.  For software which is copyrighted by the Free\n\
1324    Software Foundation, write to the Free Software Foundation; we sometimes\n\
1325    make exceptions for this.  Our decision will be guided by the two goals\n\
1326    of preserving the free status of all derivatives of our free software and\n\
1327    of promoting the sharing and reuse of software generally.\n");
1328    }
1329    
1330    extern void warranty(environment *env)
1331    {
1332      printf("                          NO WARRANTY\n\
1333    \n\
1334      11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY\n\
1335    FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN\n\
1336    OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES\n\
1337    PROVIDE THE PROGRAM \"AS IS\" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED\n\
1338    OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF\n\
1339    MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS\n\
1340    TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE\n\
1341    PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,\n\
1342    REPAIR OR CORRECTION.\n\
1343    \n\
1344      12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING\n\
1345    WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR\n\
1346    REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,\n\
1347    INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING\n\
1348    OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED\n\
1349    TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY\n\
1350    YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER\n\
1351    PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE\n\
1352    POSSIBILITY OF SUCH DAMAGES.\n");
1353    }
1354    
1355    /* General assoc function */
1356    void assocgen(environment *env, funcp eqfunc)
1357    {
1358      value *key, *item;
1359    
1360      /* Needs two values on the stack, the top one must be an association
1361         list */
1362      if(env->head->type==empty || CDR(env->head)->type==empty) {
1363        printerr("Too Few Arguments");
1364        env->err= 1;
1365        return;
1366      }
1367    
1368      if(CAR(env->head)->type!=tcons) {
1369        printerr("Bad Argument Type");
1370        env->err= 2;
1371        return;
1372      }
1373    
1374      key=CAR(CDR(env->head));
1375      item=CAR(env->head);
1376    
1377      while(item->type == tcons){
1378        if(CAR(item)->type != tcons){
1379          printerr("Bad Argument Type");
1380          env->err= 2;
1381          return;
1382        }
1383        push_val(env, key);
1384        push_val(env, CAR(CAR(item)));
1385        eqfunc(env); if(env->err) return;
1386    
1387        /* Check the result of 'eqfunc' */
1388        if(env->head->type==empty) {
1389          printerr("Too Few Arguments");
1390          env->err= 1;
1391        return;
1392        }
1393        if(CAR(env->head)->type!=integer) {
1394          printerr("Bad Argument Type");
1395          env->err= 2;
1396          return;
1397        }
1398    
1399        if(CAR(env->head)->content.i){
1400          toss(env); if(env->err) return;
1401          break;
1402        }
1403        toss(env); if(env->err) return;
1404    
1405        if(item->type!=tcons) {
1406          printerr("Bad Argument Type");
1407          env->err= 2;
1408          return;
1409        }
1410    
1411        item=CDR(item);
1412      }
1413    
1414      if(item->type == tcons){      /* A match was found */
1415        push_val(env, CAR(item));
1416      } else {
1417        push_int(env, 0);
1418      }
1419      swap(env); if(env->err) return;
1420      toss(env); if(env->err) return;
1421      swap(env); if(env->err) return;
1422      toss(env);
1423    }
1424    
1425    /* Discard the top element of the stack. */
1426    extern void toss(environment *env)
1427    {
1428      if(env->head->type==empty) {
1429        printerr("Too Few Arguments");
1430        env->err= 1;
1431        return;
1432      }
1433      
1434      env->head= CDR(env->head); /* Remove the top stack item */
1435  }  }
1436    
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