/[cvs]/stack/stack.c
ViewVC logotype

Diff of /stack/stack.c

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 1.30 by teddy, Tue Feb 5 12:33:21 2002 UTC revision 1.38 by teddy, Wed Feb 6 11:15:05 2002 UTC
# Line 18  typedef struct { Line 18  typedef struct {
18    enum {    enum {
19      integer,      integer,
20      string,      string,
     ref,                        /* Reference (to an element in the  
                                    hash table) */  
21      func,                       /* Function pointer */      func,                       /* Function pointer */
22      symb,      symb,
23      list      list
# Line 58  typedef struct stackitem_struct Line 56  typedef struct stackitem_struct
56  typedef struct {  typedef struct {
57    stackitem *head;              /* Head of the stack */    stackitem *head;              /* Head of the stack */
58    hashtbl symbols;              /* Hash table of all variable bindings */    hashtbl symbols;              /* Hash table of all variable bindings */
59      int err;                      /* Error flag */
60  } environment;  } environment;
61    
62  /* A type for pointers to external functions */  /* A type for pointers to external functions */
# Line 69  void init_env(environment *env) Line 68  void init_env(environment *env)
68  {  {
69    long i;    long i;
70    
71      env->err=0;
72    for(i= 0; i<HASHTBLSIZE; i++)    for(i= 0; i<HASHTBLSIZE; i++)
73      env->symbols[i]= NULL;      env->symbols[i]= NULL;
74  }  }
# Line 103  symbol **hash(hashtbl in_hashtbl, const Line 103  symbol **hash(hashtbl in_hashtbl, const
103  }  }
104    
105  /* Generic push function. */  /* Generic push function. */
106  int push(stackitem** stack_head, stackitem* in_item)  void push(stackitem** stack_head, stackitem* in_item)
107  {  {
108    in_item->next= *stack_head;    in_item->next= *stack_head;
109    *stack_head= in_item;    *stack_head= in_item;
   return 1;  
110  }  }
111    
112  /* Push a value onto the stack */  /* Push a value onto the stack */
# Line 120  void push_val(stackitem **stack_head, va Line 119  void push_val(stackitem **stack_head, va
119  }  }
120    
121  /* Push an integer onto the stack. */  /* Push an integer onto the stack. */
122  int push_int(stackitem **stack_head, int in_val)  void push_int(stackitem **stack_head, int in_val)
123  {  {
124    value *new_value= malloc(sizeof(value));    value *new_value= malloc(sizeof(value));
125    stackitem *new_item= malloc(sizeof(stackitem));    stackitem *new_item= malloc(sizeof(stackitem));
# Line 131  int push_int(stackitem **stack_head, int Line 130  int push_int(stackitem **stack_head, int
130    new_value->refcount=1;    new_value->refcount=1;
131    
132    push(stack_head, new_item);    push(stack_head, new_item);
   return 1;  
133  }  }
134    
135  /* Copy a string onto the stack. */  /* Copy a string onto the stack. */
136  int push_cstring(stackitem **stack_head, const char *in_string)  void push_cstring(stackitem **stack_head, const char *in_string)
137  {  {
138    value *new_value= malloc(sizeof(value));    value *new_value= malloc(sizeof(value));
139    stackitem *new_item= malloc(sizeof(stackitem));    stackitem *new_item= malloc(sizeof(stackitem));
# Line 147  int push_cstring(stackitem **stack_head, Line 145  int push_cstring(stackitem **stack_head,
145    new_value->refcount=1;    new_value->refcount=1;
146    
147    push(stack_head, new_item);    push(stack_head, new_item);
   return 1;  
148  }  }
149    
150  /* Push a symbol onto the stack. */  /* Push a symbol onto the stack. */
151  int push_sym(environment *env, const char *in_string)  void push_sym(environment *env, const char *in_string)
152  {  {
153    stackitem *new_item;          /* The new stack item */    stackitem *new_item;          /* The new stack item */
154    /* ...which will contain... */    /* ...which will contain... */
# Line 206  int push_sym(environment *env, const cha Line 203  int push_sym(environment *env, const cha
203      }      }
204    }    }
205    push(&(env->head), new_item);    push(&(env->head), new_item);
   return 1;  
206  }  }
207    
208  void printerr(const char* in_string) {  void printerr(const char* in_string) {
# Line 222  void free_val(value *val){ Line 218  void free_val(value *val){
218      switch (val->type){         /* and free the contents if necessary */      switch (val->type){         /* and free the contents if necessary */
219      case string:      case string:
220        free(val->content.ptr);        free(val->content.ptr);
221          break;
222      case list:                  /* lists needs to be freed recursively */      case list:                  /* lists needs to be freed recursively */
223        item=val->content.ptr;        item=val->content.ptr;
224        while(item != NULL) {     /* for all stack items */        while(item != NULL) {     /* for all stack items */
# Line 244  extern void toss(environment *env) Line 241  extern void toss(environment *env)
241    stackitem *temp= env->head;    stackitem *temp= env->head;
242    
243    if((env->head)==NULL) {    if((env->head)==NULL) {
244      printerr("Stack empty");      printerr("Too Few Arguments");
245        env->err=1;
246      return;      return;
247    }    }
248        
# Line 259  extern void nl() Line 257  extern void nl()
257    printf("\n");    printf("\n");
258  }  }
259    
260  /* Prints the top element of the stack. */  /* Gets the type of a value */
261  void print_h(stackitem *stack_head)  extern void type(environment *env){
262  {    int typenum;
263    
264    if(stack_head==NULL) {    if((env->head)==NULL) {
265      printerr("Stack empty");      printerr("Too Few Arguments");
266        env->err=1;
267      return;      return;
268    }    }
269      typenum=env->head->item->type;
270      toss(env);
271      switch(typenum){
272      case integer:
273        push_sym(env, "integer");
274        break;
275      case string:
276        push_sym(env, "string");
277        break;
278      case symb:
279        push_sym(env, "symbol");
280        break;
281      case func:
282        push_sym(env, "function");
283        break;
284      case list:
285        push_sym(env, "list");
286        break;
287      default:
288        push_sym(env, "unknown");
289        break;
290      }
291    }    
292    
293    /* Prints the top element of the stack. */
294    void print_h(stackitem *stack_head)
295    {
296    switch(stack_head->item->type) {    switch(stack_head->item->type) {
297    case integer:    case integer:
298      printf("%d", stack_head->item->content.val);      printf("%d", stack_head->item->content.val);
# Line 278  void print_h(stackitem *stack_head) Line 303  void print_h(stackitem *stack_head)
303    case symb:    case symb:
304      printf("'%s'", ((symbol *)(stack_head->item->content.ptr))->id);      printf("'%s'", ((symbol *)(stack_head->item->content.ptr))->id);
305      break;      break;
306      case func:
307        printf("#<function %p>", (funcp)(stack_head->item->content.ptr));
308        break;
309      case list:
310        /* A list is just a stack, so make stack_head point to it */
311        stack_head=(stackitem *)(stack_head->item->content.ptr);
312        printf("[ ");
313        while(stack_head != NULL) {
314          print_h(stack_head);
315          printf(" ");
316          stack_head=stack_head->next;
317        }
318        printf("] ");
319        break;
320    default:    default:
321      printf("%p", (funcp)(stack_head->item->content.ptr));      printf("#<unknown %p>", (stack_head->item->content.ptr));
322      break;      break;
323    }    }
324  }  }
325    
326  extern void print_(environment *env) {  extern void print_(environment *env) {
327      if(env->head==NULL) {
328        printerr("Too Few Arguments");
329        env->err=1;
330        return;
331      }
332    print_h(env->head);    print_h(env->head);
333  }  }
334    
# Line 292  extern void print_(environment *env) { Line 336  extern void print_(environment *env) {
336  extern void print(environment *env)  extern void print(environment *env)
337  {  {
338    print_(env);    print_(env);
339      if(env->err) return;
340    toss(env);    toss(env);
341  }  }
342    
# Line 310  void print_st(stackitem *stack_head, lon Line 355  void print_st(stackitem *stack_head, lon
355  /* Prints the stack. */  /* Prints the stack. */
356  extern void printstack(environment *env)  extern void printstack(environment *env)
357  {  {
358    if(env->head != NULL) {    if(env->head == NULL) {
359      print_st(env->head, 1);      return;
     nl();  
   } else {  
     printerr("Stack empty");  
360    }    }
361      print_st(env->head, 1);
362      nl();
363  }  }
364    
365  /* Swap the two top elements on the stack. */  /* Swap the two top elements on the stack. */
# Line 324  extern void swap(environment *env) Line 368  extern void swap(environment *env)
368    stackitem *temp= env->head;    stackitem *temp= env->head;
369        
370    if((env->head)==NULL) {    if((env->head)==NULL) {
371      printerr("Stack empty");      printerr("Too Few Arguments");
372        env->err=1;
373      return;      return;
374    }    }
375    
376    if(env->head->next==NULL) {    if(env->head->next==NULL) {
377      printerr("Not enough arguments");      printerr("Too Few Arguments");
378        env->err=1;
379      return;      return;
380    }    }
381    
# Line 348  stackitem* copy(stackitem* in_item) Line 394  stackitem* copy(stackitem* in_item)
394    return out_item;    return out_item;
395  }  }
396    
397    /* Recall a value from a symbol, if bound */
398    extern void rcl(environment *env)
399    {
400      value *val;
401    
402      if(env->head == NULL) {
403        printerr("Too Few Arguments");
404        env->err=1;
405        return;
406      }
407    
408      if(env->head->item->type!=symb) {
409        printerr("Bad Argument Type");
410        env->err=2;
411        return;
412      }
413    
414      val=((symbol *)(env->head->item->content.ptr))->val;
415      if(val == NULL){
416        printerr("Unbound Variable");
417        env->err=3;
418        return;
419      }
420      toss(env);            /* toss the symbol */
421      if(env->err) return;
422      push_val(&(env->head), val); /* Return its bound value */
423    }
424    
425  /* 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
426     function value, and if it is, toss the symbol and execute the     function value, and if it is, toss the symbol and execute the
# Line 355  stackitem* copy(stackitem* in_item) Line 428  stackitem* copy(stackitem* in_item)
428  extern void eval(environment *env)  extern void eval(environment *env)
429  {  {
430    funcp in_func;    funcp in_func;
   value* val;  
431    if(env->head==NULL) {    if(env->head==NULL) {
432      printerr("Stack empty");      printerr("Too Few Arguments");
433        env->err=1;
434      return;      return;
435    }    }
436    
437    /* if it's a symbol */    /* if it's a symbol */
438    if(env->head->item->type==symb) {    if(env->head->item->type==symb) {
439    
440      /* If it's not bound to anything */      rcl(env);                   /* get its contents */
441      if (((symbol *)(env->head->item->content.ptr))->val == NULL) {      if(env->err) return;
442        printerr("Unbound variable");      if(env->head->item->type!=symb){ /* don't recurse symbols */
443        return;        eval(env);                        /* evaluate the value */
     }  
       
     /* If it contains a function */  
     if (((symbol *)(env->head->item->content.ptr))->val->type == func) {  
       in_func=  
         (funcp)(((symbol *)(env->head->item->content.ptr))->val->content.ptr);  
       toss(env);  
       (*in_func)(env);          /* Run the function */  
444        return;        return;
     } else {                    /* If it's not a function */  
       val=((symbol *)(env->head->item->content.ptr))->val;  
       toss(env);                /* toss the symbol */  
       push_val(&(env->head), val); /* Return its bound value */  
445      }      }
446    }    }
447    
# Line 388  extern void eval(environment *env) Line 449  extern void eval(environment *env)
449    if(env->head->item->type==func) {    if(env->head->item->type==func) {
450      in_func= (funcp)(env->head->item->content.ptr);      in_func= (funcp)(env->head->item->content.ptr);
451      toss(env);      toss(env);
452        if(env->err) return;
453      (*in_func)(env);      (*in_func)(env);
     return;  
454    }    }
   
455  }  }
456    
457  /* Make a list. */  /* Make a list. */
# Line 437  extern void pack(environment *env) Line 497  extern void pack(environment *env)
497  }  }
498    
499  /* Parse input. */  /* Parse input. */
500  int stack_read(environment *env, char *in_line)  void stack_read(environment *env, char *in_line)
501  {  {
502    char *temp, *rest;    char *temp, *rest;
503    int itemp;    int itemp;
# Line 466  int stack_read(environment *env, char *i Line 526  int stack_read(environment *env, char *i
526        break;        break;
527      }      }
528      /* If symbol */      /* If symbol */
529      if((convert= sscanf(in_line, "%[^][ ;\n\r_]%[^\n\r]", temp, rest))) {      if((convert= sscanf(in_line, "%[^][ ;\n\r]%[^\n\r]", temp, rest))) {
530          push_sym(env, temp);          push_sym(env, temp);
531          break;          break;
532      }      }
# Line 498  int stack_read(environment *env, char *i Line 558  int stack_read(environment *env, char *i
558      }      }
559    } while(0);    } while(0);
560    
   
561    free(temp);    free(temp);
562    
563    if(convert<2) {    if(convert<2) {
564      free(rest);      free(rest);
565      return 0;      return;
566    }    }
567        
568    stack_read(env, rest);    stack_read(env, rest);
569        
570    free(rest);    free(rest);
   return 1;  
571  }  }
572    
573  /* Relocate elements of the list on the stack. */  /* Relocate elements of the list on the stack. */
# Line 518  extern void expand(environment *env) Line 576  extern void expand(environment *env)
576    stackitem *temp, *new_head;    stackitem *temp, *new_head;
577    
578    /* Is top element a list? */    /* Is top element a list? */
579    if(env->head==NULL || env->head->item->type!=list) {    if(env->head==NULL) {
580      printerr("Stack empty or not a list");      printerr("Too Few Arguments");
581        env->err=1;
582        return;
583      }
584      if(env->head->item->type!=list) {
585        printerr("Bad Argument Type");
586        env->err=2;
587      return;      return;
588    }    }
589    
# Line 546  extern void eq(environment *env) Line 610  extern void eq(environment *env)
610    int result;    int result;
611    
612    if((env->head)==NULL || env->head->next==NULL) {    if((env->head)==NULL || env->head->next==NULL) {
613      printerr("Not enough elements to compare");      printerr("Too Few Arguments");
614        env->err=1;
615      return;      return;
616    }    }
617    
# Line 564  extern void not(environment *env) Line 629  extern void not(environment *env)
629  {  {
630    int val;    int val;
631    
632    if((env->head)==NULL || env->head->item->type!=integer) {    if((env->head)==NULL) {
633      printerr("Stack empty or element is not a integer");      printerr("Too Few Arguments");
634        env->err=1;
635        return;
636      }
637    
638      if(env->head->item->type!=integer) {
639        printerr("Bad Argument Type");
640        env->err=2;
641      return;      return;
642    }    }
643    
# Line 588  extern void def(environment *env) Line 660  extern void def(environment *env)
660    symbol *sym;    symbol *sym;
661    
662    /* Needs two values on the stack, the top one must be a symbol */    /* Needs two values on the stack, the top one must be a symbol */
663    if(env->head==NULL || env->head->next==NULL    if(env->head==NULL || env->head->next==NULL) {
664       || env->head->item->type!=symb) {      printerr("Too Few Arguments");
665      printerr("Define what?");      env->err=1;
666        return;
667      }
668    
669      if(env->head->item->type!=symb) {
670        printerr("Bad Argument Type");
671        env->err=2;
672      return;      return;
673    }    }
674    
# Line 621  extern void clear(environment *env) Line 699  extern void clear(environment *env)
699      toss(env);      toss(env);
700  }  }
701    
702    /* List all defined words */
703    extern void words(environment *env)
704    {
705      symbol *temp;
706      int i;
707      
708      for(i= 0; i<HASHTBLSIZE; i++) {
709        temp= env->symbols[i];
710        while(temp!=NULL) {
711          printf("%s\n", temp->id);
712          temp= temp->next;
713        }
714      }
715    }
716    
717    /* Forgets a symbol (remove it from the hash table) */
718    extern void forget(environment *env)
719    {
720      char* sym_id;
721      stackitem *stack_head= env->head;
722      symbol **hash_entry, *temp;
723    
724      if(stack_head==NULL) {
725        printerr("Too Few Arguments");
726        env->err=1;
727        return;
728      }
729      
730      if(stack_head->item->type!=symb) {
731        printerr("Bad Argument Type");
732        env->err=2;
733        return;
734      }
735    
736      sym_id= ((symbol*)(stack_head->item->content.ptr))->id;
737      toss(env);
738    
739      hash_entry= hash(env->symbols, sym_id);
740      temp= *hash_entry;
741      *hash_entry= (*hash_entry)->next;
742      
743      if(temp->val!=NULL) {
744        free_val(temp->val);
745      }
746      free(temp->id);
747      free(temp);
748    }
749    
750    /* Returns the current error number to the stack */
751    extern void errn(environment *env){
752      push_int(&(env->head), env->err);
753    }
754    
755  int main()  int main()
756  {  {
757    environment myenv;    environment myenv;
# Line 632  int main() Line 763  int main()
763    
764    while(fgets(in_string, 100, stdin) != NULL) {    while(fgets(in_string, 100, stdin) != NULL) {
765      stack_read(&myenv, in_string);      stack_read(&myenv, in_string);
766        if(myenv.err) {
767          printf("(error %d) ", myenv.err);
768          myenv.err=0;
769        }
770      printf("okidok\n ");      printf("okidok\n ");
771    }    }
772    
Legend:
Removed from v.1.30  
changed lines
  Added in v.1.38
root@recompile.se
 ViewVC Help
Powered by ViewVC 1.1.26