/[cvs]/stack/stack.c
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revision 1.29 by teddy, Tue Feb 5 12:14:42 2002 UTC revision 1.40 by teddy, Wed Feb 6 11:44:02 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 178  int push_sym(environment *env, const cha Line 175  int push_sym(environment *env, const cha
175    new_symbol= hash(env->symbols, in_string);    new_symbol= hash(env->symbols, in_string);
176    new_value->content.ptr= *new_symbol;    new_value->content.ptr= *new_symbol;
177    
178    if(new_value->content.ptr==NULL) { /* If symbol was undefined */    if(*new_symbol==NULL) { /* If symbol was undefined */
179    
180      /* Create a new symbol */      /* Create a new symbol */
181      *new_symbol= malloc(sizeof(symbol));      (*new_symbol)= malloc(sizeof(symbol));
182      (*new_symbol)->val= NULL;   /* undefined value */      (*new_symbol)->val= NULL;   /* undefined value */
183      (*new_symbol)->next= NULL;      (*new_symbol)->next= NULL;
184      (*new_symbol)->id= malloc(strlen(in_string)+1);      (*new_symbol)->id= malloc(strlen(in_string)+1);
# 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          eval(env);                        /* evaluate the value */
444        return;        return;
445      }      }
       
     /* 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 */  
       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 */  
     }  
446    }    }
447    
448    /* If it's a lone function value, run it */    /* If it's a lone function value, run it */
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);
454      }
455    }
456    
457    /* Reverse a list */
458    extern void rev(environment *env){
459      stackitem *old_head, *new_head, *item;
460    
461      if((env->head)==NULL) {
462        printerr("Too Few Arguments");
463        env->err=1;
464        return;
465      }
466    
467      if(env->head->item->type!=list) {
468        printerr("Bad Argument Type");
469        env->err=2;
470      return;      return;
471    }    }
472    
473  /*    push(&(env->head), copy(env->head)); */    old_head=(stackitem *)(env->head->item->content.ptr);
474  /*    swap(env); */    new_head=NULL;
475  /*    toss(env); */    while(old_head != NULL){
476        item=old_head;
477        old_head=old_head->next;
478        item->next=new_head;
479        new_head=item;
480      }
481      env->head->item->content.ptr=new_head;
482  }  }
483    
484  /* Make a list. */  /* Make a list. */
# Line 437  extern void pack(environment *env) Line 521  extern void pack(environment *env)
521    temp->item= pack;    temp->item= pack;
522    
523    push(&(env->head), temp);    push(&(env->head), temp);
524      rev(env);
525  }  }
526    
527  /* Parse input. */  /* Parse input. */
528  int stack_read(environment *env, char *in_line)  void stack_read(environment *env, char *in_line)
529  {  {
530    char *temp, *rest;    char *temp, *rest;
531    int itemp;    int itemp;
# Line 469  int stack_read(environment *env, char *i Line 554  int stack_read(environment *env, char *i
554        break;        break;
555      }      }
556      /* If symbol */      /* If symbol */
557      if((convert= sscanf(in_line, "%[^][ ;\n\r_]%[^\n\r]", temp, rest))) {      if((convert= sscanf(in_line, "%[^][ ;\n\r]%[^\n\r]", temp, rest))) {
558          push_sym(env, temp);          push_sym(env, temp);
559          break;          break;
560      }      }
# Line 501  int stack_read(environment *env, char *i Line 586  int stack_read(environment *env, char *i
586      }      }
587    } while(0);    } while(0);
588    
   
589    free(temp);    free(temp);
590    
591    if(convert<2) {    if(convert<2) {
592      free(rest);      free(rest);
593      return 0;      return;
594    }    }
595        
596    stack_read(env, rest);    stack_read(env, rest);
597        
598    free(rest);    free(rest);
   return 1;  
599  }  }
600    
601  /* Relocate elements of the list on the stack. */  /* Relocate elements of the list on the stack. */
# Line 521  extern void expand(environment *env) Line 604  extern void expand(environment *env)
604    stackitem *temp, *new_head;    stackitem *temp, *new_head;
605    
606    /* Is top element a list? */    /* Is top element a list? */
607    if(env->head==NULL || env->head->item->type!=list) {    if(env->head==NULL) {
608      printerr("Stack empty or not a list");      printerr("Too Few Arguments");
609        env->err=1;
610        return;
611      }
612      if(env->head->item->type!=list) {
613        printerr("Bad Argument Type");
614        env->err=2;
615      return;      return;
616    }    }
617    
# Line 549  extern void eq(environment *env) Line 638  extern void eq(environment *env)
638    int result;    int result;
639    
640    if((env->head)==NULL || env->head->next==NULL) {    if((env->head)==NULL || env->head->next==NULL) {
641      printerr("Not enough elements to compare");      printerr("Too Few Arguments");
642        env->err=1;
643      return;      return;
644    }    }
645    
# Line 567  extern void not(environment *env) Line 657  extern void not(environment *env)
657  {  {
658    int val;    int val;
659    
660    if((env->head)==NULL || env->head->item->type!=integer) {    if((env->head)==NULL) {
661      printerr("Stack empty or element is not a integer");      printerr("Too Few Arguments");
662        env->err=1;
663        return;
664      }
665    
666      if(env->head->item->type!=integer) {
667        printerr("Bad Argument Type");
668        env->err=2;
669      return;      return;
670    }    }
671    
# Line 591  extern void def(environment *env) Line 688  extern void def(environment *env)
688    symbol *sym;    symbol *sym;
689    
690    /* 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 */
691    if(env->head==NULL || env->head->next==NULL    if(env->head==NULL || env->head->next==NULL) {
692       || env->head->item->type!=symb) {      printerr("Too Few Arguments");
693      printerr("Define what?");      env->err=1;
694        return;
695      }
696    
697      if(env->head->item->type!=symb) {
698        printerr("Bad Argument Type");
699        env->err=2;
700      return;      return;
701    }    }
702    
# Line 624  extern void clear(environment *env) Line 727  extern void clear(environment *env)
727      toss(env);      toss(env);
728  }  }
729    
730    /* List all defined words */
731    extern void words(environment *env)
732    {
733      symbol *temp;
734      int i;
735      
736      for(i= 0; i<HASHTBLSIZE; i++) {
737        temp= env->symbols[i];
738        while(temp!=NULL) {
739          printf("%s\n", temp->id);
740          temp= temp->next;
741        }
742      }
743    }
744    
745    /* Forgets a symbol (remove it from the hash table) */
746    extern void forget(environment *env)
747    {
748      char* sym_id;
749      stackitem *stack_head= env->head;
750      symbol **hash_entry, *temp;
751    
752      if(stack_head==NULL) {
753        printerr("Too Few Arguments");
754        env->err=1;
755        return;
756      }
757      
758      if(stack_head->item->type!=symb) {
759        printerr("Bad Argument Type");
760        env->err=2;
761        return;
762      }
763    
764      sym_id= ((symbol*)(stack_head->item->content.ptr))->id;
765      toss(env);
766    
767      hash_entry= hash(env->symbols, sym_id);
768      temp= *hash_entry;
769      *hash_entry= (*hash_entry)->next;
770      
771      if(temp->val!=NULL) {
772        free_val(temp->val);
773      }
774      free(temp->id);
775      free(temp);
776    }
777    
778    /* Returns the current error number to the stack */
779    extern void errn(environment *env){
780      push_int(&(env->head), env->err);
781    }
782    
783  int main()  int main()
784  {  {
785    environment myenv;    environment myenv;
# Line 635  int main() Line 791  int main()
791    
792    while(fgets(in_string, 100, stdin) != NULL) {    while(fgets(in_string, 100, stdin) != NULL) {
793      stack_read(&myenv, in_string);      stack_read(&myenv, in_string);
794        if(myenv.err) {
795          printf("(error %d) ", myenv.err);
796          myenv.err=0;
797        }
798      printf("okidok\n ");      printf("okidok\n ");
799    }    }
800    
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