1 |
/* printf, sscanf, fgets, fprintf */ |
2 |
#include <stdio.h> |
3 |
/* exit, EXIT_SUCCESS, malloc, free */ |
4 |
#include <stdlib.h> |
5 |
/* NULL */ |
6 |
#include <stddef.h> |
7 |
/* dlopen, dlsym, dlerror */ |
8 |
#include <dlfcn.h> |
9 |
/* strcmp, strcpy, strlen, strcat, strdup */ |
10 |
#include <string.h> |
11 |
|
12 |
#define HASHTBLSIZE 65536 |
13 |
|
14 |
/* First, define some types. */ |
15 |
|
16 |
/* A value of some type */ |
17 |
typedef struct { |
18 |
enum { |
19 |
integer, |
20 |
string, |
21 |
func, /* Function pointer */ |
22 |
symb, |
23 |
list |
24 |
} type; /* Type of stack element */ |
25 |
|
26 |
union { |
27 |
void *ptr; /* Pointer to the content */ |
28 |
int val; /* ...or an integer */ |
29 |
} content; /* Stores a pointer or an integer */ |
30 |
|
31 |
int refcount; /* Reference counter */ |
32 |
|
33 |
} value; |
34 |
|
35 |
/* A symbol with a name and possible value */ |
36 |
/* (These do not need reference counters, they are kept unique by |
37 |
hashing.) */ |
38 |
typedef struct symbol_struct { |
39 |
char *id; /* Symbol name */ |
40 |
value *val; /* The value (if any) bound to it */ |
41 |
struct symbol_struct *next; /* In case of hashing conflicts, a */ |
42 |
} symbol; /* symbol is a kind of stack item. */ |
43 |
|
44 |
/* A type for a hash table for symbols */ |
45 |
typedef symbol *hashtbl[HASHTBLSIZE]; /* Hash table declaration */ |
46 |
|
47 |
/* An item (value) on a stack */ |
48 |
typedef struct stackitem_struct |
49 |
{ |
50 |
value *item; /* The value on the stack */ |
51 |
struct stackitem_struct *next; /* Next item */ |
52 |
} stackitem; |
53 |
|
54 |
/* An environment; gives access to the stack and a hash table of |
55 |
defined symbols */ |
56 |
typedef struct { |
57 |
stackitem *head; /* Head of the stack */ |
58 |
hashtbl symbols; /* Hash table of all variable bindings */ |
59 |
int err; /* Error flag */ |
60 |
int non_eval_flag; |
61 |
} environment; |
62 |
|
63 |
/* A type for pointers to external functions */ |
64 |
typedef void (*funcp)(environment *); /* funcp is a pointer to a void |
65 |
function (environment *) */ |
66 |
|
67 |
/* Initialize a newly created environment */ |
68 |
void init_env(environment *env) |
69 |
{ |
70 |
int i; |
71 |
|
72 |
env->err= 0; |
73 |
env->non_eval_flag= 0; |
74 |
for(i= 0; i<HASHTBLSIZE; i++) |
75 |
env->symbols[i]= NULL; |
76 |
} |
77 |
|
78 |
void printerr(const char* in_string) { |
79 |
fprintf(stderr, "Err: %s\n", in_string); |
80 |
} |
81 |
|
82 |
/* Throw away a value */ |
83 |
void free_val(value *val){ |
84 |
stackitem *item, *temp; |
85 |
|
86 |
val->refcount--; /* Decrease the reference count */ |
87 |
if(val->refcount == 0){ |
88 |
switch (val->type){ /* and free the contents if necessary */ |
89 |
case string: |
90 |
free(val->content.ptr); |
91 |
break; |
92 |
case list: /* lists needs to be freed recursively */ |
93 |
item=val->content.ptr; |
94 |
while(item != NULL) { /* for all stack items */ |
95 |
free_val(item->item); /* free the value */ |
96 |
temp=item->next; /* save next ptr */ |
97 |
free(item); /* free the stackitem */ |
98 |
item=temp; /* go to next stackitem */ |
99 |
} |
100 |
free(val); /* Free the actual list value */ |
101 |
break; |
102 |
default: |
103 |
break; |
104 |
} |
105 |
} |
106 |
} |
107 |
|
108 |
/* Discard the top element of the stack. */ |
109 |
extern void toss(environment *env) |
110 |
{ |
111 |
stackitem *temp= env->head; |
112 |
|
113 |
if((env->head)==NULL) { |
114 |
printerr("Too Few Arguments"); |
115 |
env->err=1; |
116 |
return; |
117 |
} |
118 |
|
119 |
free_val(env->head->item); /* Free the value */ |
120 |
env->head= env->head->next; /* Remove the top stack item */ |
121 |
free(temp); /* Free the old top stack item */ |
122 |
} |
123 |
|
124 |
/* Returns a pointer to a pointer to an element in the hash table. */ |
125 |
symbol **hash(hashtbl in_hashtbl, const char *in_string) |
126 |
{ |
127 |
int i= 0; |
128 |
unsigned int out_hash= 0; |
129 |
char key= '\0'; |
130 |
symbol **position; |
131 |
|
132 |
while(1){ /* Hash in_string */ |
133 |
key= in_string[i++]; |
134 |
if(key=='\0') |
135 |
break; |
136 |
out_hash= out_hash*32+key; |
137 |
} |
138 |
|
139 |
out_hash= out_hash%HASHTBLSIZE; |
140 |
position= &(in_hashtbl[out_hash]); |
141 |
|
142 |
while(1){ |
143 |
if(*position==NULL) /* If empty */ |
144 |
return position; |
145 |
|
146 |
if(strcmp(in_string, (*position)->id)==0) /* If match */ |
147 |
return position; |
148 |
|
149 |
position= &((*position)->next); /* Try next */ |
150 |
} |
151 |
} |
152 |
|
153 |
/* Generic push function. */ |
154 |
void push(stackitem** stack_head, stackitem* in_item) |
155 |
{ |
156 |
in_item->next= *stack_head; |
157 |
*stack_head= in_item; |
158 |
} |
159 |
|
160 |
/* Push a value onto the stack */ |
161 |
void push_val(stackitem **stack_head, value *val) |
162 |
{ |
163 |
stackitem *new_item= malloc(sizeof(stackitem)); |
164 |
new_item->item= val; |
165 |
val->refcount++; |
166 |
push(stack_head, new_item); |
167 |
} |
168 |
|
169 |
/* Push an integer onto the stack. */ |
170 |
void push_int(stackitem **stack_head, int in_val) |
171 |
{ |
172 |
value *new_value= malloc(sizeof(value)); |
173 |
stackitem *new_item= malloc(sizeof(stackitem)); |
174 |
new_item->item= new_value; |
175 |
|
176 |
new_value->content.val= in_val; |
177 |
new_value->type= integer; |
178 |
new_value->refcount=1; |
179 |
|
180 |
push(stack_head, new_item); |
181 |
} |
182 |
|
183 |
/* Copy a string onto the stack. */ |
184 |
void push_cstring(stackitem **stack_head, const char *in_string) |
185 |
{ |
186 |
value *new_value= malloc(sizeof(value)); |
187 |
stackitem *new_item= malloc(sizeof(stackitem)); |
188 |
new_item->item=new_value; |
189 |
|
190 |
new_value->content.ptr= malloc(strlen(in_string)+1); |
191 |
strcpy(new_value->content.ptr, in_string); |
192 |
new_value->type= string; |
193 |
new_value->refcount=1; |
194 |
|
195 |
push(stack_head, new_item); |
196 |
} |
197 |
|
198 |
/* Mangle a symbol name to a valid C identifier name */ |
199 |
char *mangle_str(const char *old_string){ |
200 |
char validchars[] |
201 |
="0123456789abcdef"; |
202 |
char *new_string, *current; |
203 |
|
204 |
new_string=malloc((strlen(old_string)*2)+4); |
205 |
strcpy(new_string, "sx_"); /* Stack eXternal */ |
206 |
current=new_string+3; |
207 |
while(old_string[0] != '\0'){ |
208 |
current[0]=validchars[old_string[0]/16]; |
209 |
current[1]=validchars[old_string[0]%16]; |
210 |
current+=2; |
211 |
old_string++; |
212 |
} |
213 |
current[0]='\0'; |
214 |
|
215 |
return new_string; /* The caller must free() it */ |
216 |
} |
217 |
|
218 |
extern void mangle(environment *env){ |
219 |
value *new_value; |
220 |
char *new_string; |
221 |
|
222 |
if((env->head)==NULL) { |
223 |
printerr("Too Few Arguments"); |
224 |
env->err=1; |
225 |
return; |
226 |
} |
227 |
|
228 |
if(env->head->item->type!=string) { |
229 |
printerr("Bad Argument Type"); |
230 |
env->err=2; |
231 |
return; |
232 |
} |
233 |
|
234 |
new_string= mangle_str((const char *)(env->head->item->content.ptr)); |
235 |
|
236 |
toss(env); |
237 |
if(env->err) return; |
238 |
|
239 |
new_value= malloc(sizeof(value)); |
240 |
new_value->content.ptr= new_string; |
241 |
new_value->type= string; |
242 |
new_value->refcount=1; |
243 |
|
244 |
push_val(&(env->head), new_value); |
245 |
} |
246 |
|
247 |
/* Push a symbol onto the stack. */ |
248 |
void push_sym(environment *env, const char *in_string) |
249 |
{ |
250 |
stackitem *new_item; /* The new stack item */ |
251 |
/* ...which will contain... */ |
252 |
value *new_value; /* A new symbol value */ |
253 |
/* ...which might point to... */ |
254 |
symbol **new_symbol; /* (if needed) A new actual symbol */ |
255 |
/* ...which, if possible, will be bound to... */ |
256 |
value *new_fvalue; /* (if needed) A new function value */ |
257 |
/* ...which will point to... */ |
258 |
void *funcptr; /* A function pointer */ |
259 |
|
260 |
static void *handle= NULL; /* Dynamic linker handle */ |
261 |
const char *dlerr; /* Dynamic linker error */ |
262 |
char *mangled; /* Mangled function name */ |
263 |
|
264 |
/* Create a new stack item containing a new value */ |
265 |
new_item= malloc(sizeof(stackitem)); |
266 |
new_value= malloc(sizeof(value)); |
267 |
new_item->item=new_value; |
268 |
|
269 |
/* The new value is a symbol */ |
270 |
new_value->type= symb; |
271 |
new_value->refcount= 1; |
272 |
|
273 |
/* Look up the symbol name in the hash table */ |
274 |
new_symbol= hash(env->symbols, in_string); |
275 |
new_value->content.ptr= *new_symbol; |
276 |
|
277 |
if(*new_symbol==NULL) { /* If symbol was undefined */ |
278 |
|
279 |
/* Create a new symbol */ |
280 |
(*new_symbol)= malloc(sizeof(symbol)); |
281 |
(*new_symbol)->val= NULL; /* undefined value */ |
282 |
(*new_symbol)->next= NULL; |
283 |
(*new_symbol)->id= malloc(strlen(in_string)+1); |
284 |
strcpy((*new_symbol)->id, in_string); |
285 |
|
286 |
/* Intern the new symbol in the hash table */ |
287 |
new_value->content.ptr= *new_symbol; |
288 |
|
289 |
/* Try to load the symbol name as an external function, to see if |
290 |
we should bind the symbol to a new function pointer value */ |
291 |
if(handle==NULL) /* If no handle */ |
292 |
handle= dlopen(NULL, RTLD_LAZY); |
293 |
|
294 |
funcptr= dlsym(handle, in_string); /* Get function pointer */ |
295 |
dlerr=dlerror(); |
296 |
if(dlerr != NULL) { /* If no function was found */ |
297 |
mangled=mangle_str(in_string); |
298 |
funcptr= dlsym(handle, mangled); /* try mangling it */ |
299 |
free(mangled); |
300 |
dlerr=dlerror(); |
301 |
} |
302 |
if(dlerr==NULL) { /* If a function was found */ |
303 |
new_fvalue= malloc(sizeof(value)); /* Create a new value */ |
304 |
new_fvalue->type=func; /* The new value is a function pointer */ |
305 |
new_fvalue->content.ptr=funcptr; /* Store function pointer */ |
306 |
(*new_symbol)->val= new_fvalue; /* Bind the symbol to the new |
307 |
function value */ |
308 |
new_fvalue->refcount= 1; |
309 |
} |
310 |
} |
311 |
push(&(env->head), new_item); |
312 |
} |
313 |
|
314 |
/* Print newline. */ |
315 |
extern void nl() |
316 |
{ |
317 |
printf("\n"); |
318 |
} |
319 |
|
320 |
/* Gets the type of a value */ |
321 |
extern void type(environment *env){ |
322 |
int typenum; |
323 |
|
324 |
if((env->head)==NULL) { |
325 |
printerr("Too Few Arguments"); |
326 |
env->err=1; |
327 |
return; |
328 |
} |
329 |
typenum=env->head->item->type; |
330 |
toss(env); |
331 |
switch(typenum){ |
332 |
case integer: |
333 |
push_sym(env, "integer"); |
334 |
break; |
335 |
case string: |
336 |
push_sym(env, "string"); |
337 |
break; |
338 |
case symb: |
339 |
push_sym(env, "symbol"); |
340 |
break; |
341 |
case func: |
342 |
push_sym(env, "function"); |
343 |
break; |
344 |
case list: |
345 |
push_sym(env, "list"); |
346 |
break; |
347 |
default: |
348 |
push_sym(env, "unknown"); |
349 |
break; |
350 |
} |
351 |
} |
352 |
|
353 |
/* Prints the top element of the stack. */ |
354 |
void print_h(stackitem *stack_head) |
355 |
{ |
356 |
switch(stack_head->item->type) { |
357 |
case integer: |
358 |
printf("%d", stack_head->item->content.val); |
359 |
break; |
360 |
case string: |
361 |
printf("\"%s\"", (char*)stack_head->item->content.ptr); |
362 |
break; |
363 |
case symb: |
364 |
printf("%s", ((symbol *)(stack_head->item->content.ptr))->id); |
365 |
break; |
366 |
case func: |
367 |
printf("#<function %p>", (funcp)(stack_head->item->content.ptr)); |
368 |
break; |
369 |
case list: |
370 |
/* A list is just a stack, so make stack_head point to it */ |
371 |
stack_head=(stackitem *)(stack_head->item->content.ptr); |
372 |
printf("[ "); |
373 |
while(stack_head != NULL) { |
374 |
print_h(stack_head); |
375 |
printf(" "); |
376 |
stack_head=stack_head->next; |
377 |
} |
378 |
printf("]"); |
379 |
break; |
380 |
default: |
381 |
printf("#<unknown %p>", (stack_head->item->content.ptr)); |
382 |
break; |
383 |
} |
384 |
} |
385 |
|
386 |
extern void print_(environment *env) { |
387 |
if(env->head==NULL) { |
388 |
printerr("Too Few Arguments"); |
389 |
env->err=1; |
390 |
return; |
391 |
} |
392 |
print_h(env->head); |
393 |
} |
394 |
|
395 |
/* Prints the top element of the stack and then discards it. */ |
396 |
extern void print(environment *env) |
397 |
{ |
398 |
print_(env); |
399 |
if(env->err) return; |
400 |
toss(env); |
401 |
} |
402 |
|
403 |
/* Only to be called by function printstack. */ |
404 |
void print_st(stackitem *stack_head, long counter) |
405 |
{ |
406 |
if(stack_head->next != NULL) |
407 |
print_st(stack_head->next, counter+1); |
408 |
printf("%ld: ", counter); |
409 |
print_h(stack_head); |
410 |
nl(); |
411 |
} |
412 |
|
413 |
/* Prints the stack. */ |
414 |
extern void printstack(environment *env) |
415 |
{ |
416 |
if(env->head == NULL) { |
417 |
return; |
418 |
} |
419 |
print_st(env->head, 1); |
420 |
nl(); |
421 |
} |
422 |
|
423 |
/* Swap the two top elements on the stack. */ |
424 |
extern void swap(environment *env) |
425 |
{ |
426 |
stackitem *temp= env->head; |
427 |
|
428 |
if(env->head==NULL || env->head->next==NULL) { |
429 |
printerr("Too Few Arguments"); |
430 |
env->err=1; |
431 |
return; |
432 |
} |
433 |
|
434 |
env->head= env->head->next; |
435 |
temp->next= env->head->next; |
436 |
env->head->next= temp; |
437 |
} |
438 |
|
439 |
/* Recall a value from a symbol, if bound */ |
440 |
extern void rcl(environment *env) |
441 |
{ |
442 |
value *val; |
443 |
|
444 |
if(env->head == NULL) { |
445 |
printerr("Too Few Arguments"); |
446 |
env->err=1; |
447 |
return; |
448 |
} |
449 |
|
450 |
if(env->head->item->type!=symb) { |
451 |
printerr("Bad Argument Type"); |
452 |
env->err=2; |
453 |
return; |
454 |
} |
455 |
|
456 |
val=((symbol *)(env->head->item->content.ptr))->val; |
457 |
if(val == NULL){ |
458 |
printerr("Unbound Variable"); |
459 |
env->err=3; |
460 |
return; |
461 |
} |
462 |
toss(env); /* toss the symbol */ |
463 |
if(env->err) return; |
464 |
push_val(&(env->head), val); /* Return its bound value */ |
465 |
} |
466 |
|
467 |
void stack_read(environment*, char*); |
468 |
|
469 |
/* If the top element is a symbol, determine if it's bound to a |
470 |
function value, and if it is, toss the symbol and execute the |
471 |
function. */ |
472 |
extern void eval(environment *env) |
473 |
{ |
474 |
funcp in_func; |
475 |
value* temp_val; |
476 |
stackitem* iterator; |
477 |
char* temp_string; |
478 |
|
479 |
if(env->head==NULL) { |
480 |
printerr("Too Few Arguments"); |
481 |
env->err=1; |
482 |
return; |
483 |
} |
484 |
|
485 |
switch(env->head->item->type) { |
486 |
/* if it's a symbol */ |
487 |
case symb: |
488 |
rcl(env); /* get its contents */ |
489 |
if(env->err) return; |
490 |
if(env->head->item->type!=symb){ /* don't recurse symbols */ |
491 |
eval(env); /* evaluate the value */ |
492 |
return; |
493 |
} |
494 |
break; |
495 |
|
496 |
/* If it's a lone function value, run it */ |
497 |
case func: |
498 |
in_func= (funcp)(env->head->item->content.ptr); |
499 |
toss(env); |
500 |
if(env->err) return; |
501 |
(*in_func)(env); |
502 |
break; |
503 |
|
504 |
/* If it's a list */ |
505 |
case list: |
506 |
temp_val= env->head->item; |
507 |
env->head->item->refcount++; |
508 |
toss(env); |
509 |
if(env->err) return; |
510 |
iterator= (stackitem*)temp_val->content.ptr; |
511 |
while(iterator!=NULL && iterator->item!=NULL) { |
512 |
push_val(&(env->head), iterator->item); |
513 |
if(env->head->item->type==symb |
514 |
&& strcmp(";", ((symbol*)(env->head->item->content.ptr))->id)==0) { |
515 |
toss(env); |
516 |
if(env->err) return; |
517 |
eval(env); |
518 |
if(env->err) return; |
519 |
} |
520 |
iterator= iterator->next; |
521 |
} |
522 |
free_val(temp_val); |
523 |
break; |
524 |
|
525 |
/* If it's a string */ |
526 |
case string: |
527 |
temp_val= env->head->item; |
528 |
env->head->item->refcount++; |
529 |
toss(env); |
530 |
if(env->err) return; |
531 |
temp_string= malloc(strlen((char*)temp_val->content.ptr)+5); |
532 |
strcpy(temp_string, "[ "); |
533 |
strcat(temp_string, (char*)temp_val->content.ptr); |
534 |
strcat(temp_string, " ]"); |
535 |
stack_read(env, temp_string); |
536 |
eval(env); |
537 |
if(env->err) return; |
538 |
free_val(temp_val); |
539 |
free(temp_string); |
540 |
break; |
541 |
|
542 |
default: |
543 |
} |
544 |
} |
545 |
|
546 |
/* Reverse (flip) a list */ |
547 |
extern void rev(environment *env){ |
548 |
stackitem *old_head, *new_head, *item; |
549 |
|
550 |
if((env->head)==NULL) { |
551 |
printerr("Too Few Arguments"); |
552 |
env->err=1; |
553 |
return; |
554 |
} |
555 |
|
556 |
if(env->head->item->type!=list) { |
557 |
printerr("Bad Argument Type"); |
558 |
env->err=2; |
559 |
return; |
560 |
} |
561 |
|
562 |
old_head=(stackitem *)(env->head->item->content.ptr); |
563 |
new_head=NULL; |
564 |
while(old_head != NULL){ |
565 |
item=old_head; |
566 |
old_head=old_head->next; |
567 |
item->next=new_head; |
568 |
new_head=item; |
569 |
} |
570 |
env->head->item->content.ptr=new_head; |
571 |
} |
572 |
|
573 |
/* Make a list. */ |
574 |
extern void pack(environment *env) |
575 |
{ |
576 |
void* delimiter; |
577 |
stackitem *iterator, *temp; |
578 |
value *pack; |
579 |
|
580 |
delimiter= env->head->item->content.ptr; /* Get delimiter */ |
581 |
toss(env); |
582 |
|
583 |
iterator= env->head; |
584 |
|
585 |
if(iterator==NULL || iterator->item->content.ptr==delimiter) { |
586 |
temp= NULL; |
587 |
toss(env); |
588 |
} else { |
589 |
/* Search for first delimiter */ |
590 |
while(iterator->next!=NULL |
591 |
&& iterator->next->item->content.ptr!=delimiter) |
592 |
iterator= iterator->next; |
593 |
|
594 |
/* Extract list */ |
595 |
temp= env->head; |
596 |
env->head= iterator->next; |
597 |
iterator->next= NULL; |
598 |
|
599 |
if(env->head!=NULL) |
600 |
toss(env); |
601 |
} |
602 |
|
603 |
/* Push list */ |
604 |
pack= malloc(sizeof(value)); |
605 |
pack->type= list; |
606 |
pack->content.ptr= temp; |
607 |
pack->refcount= 1; |
608 |
|
609 |
temp= malloc(sizeof(stackitem)); |
610 |
temp->item= pack; |
611 |
|
612 |
push(&(env->head), temp); |
613 |
rev(env); |
614 |
} |
615 |
|
616 |
/* Parse input. */ |
617 |
void stack_read(environment *env, char *in_line) |
618 |
{ |
619 |
char *temp, *rest; |
620 |
int itemp; |
621 |
size_t inlength= strlen(in_line)+1; |
622 |
int convert= 0; |
623 |
|
624 |
temp= malloc(inlength); |
625 |
rest= malloc(inlength); |
626 |
|
627 |
do { |
628 |
/* If comment */ |
629 |
if((convert= sscanf(in_line, "#%[^\n\r]", rest))) { |
630 |
free(temp); free(rest); |
631 |
return; |
632 |
} |
633 |
|
634 |
/* If string */ |
635 |
if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest))) { |
636 |
push_cstring(&(env->head), temp); |
637 |
break; |
638 |
} |
639 |
/* If integer */ |
640 |
if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest))) { |
641 |
push_int(&(env->head), itemp); |
642 |
break; |
643 |
} |
644 |
/* Escape ';' with '\' */ |
645 |
if((convert= sscanf(in_line, "\\%c%[^\n\r]", temp, rest))) { |
646 |
temp[1]= '\0'; |
647 |
push_sym(env, temp); |
648 |
break; |
649 |
} |
650 |
/* If symbol */ |
651 |
if((convert= sscanf(in_line, "%[^][ ;\n\r]%[^\n\r]", temp, rest))) { |
652 |
push_sym(env, temp); |
653 |
break; |
654 |
} |
655 |
/* If single char */ |
656 |
if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest))) { |
657 |
if(*temp==';') { |
658 |
if(!env->non_eval_flag) { |
659 |
eval(env); /* Evaluate top element */ |
660 |
break; |
661 |
} |
662 |
|
663 |
push_sym(env, ";"); |
664 |
break; |
665 |
} |
666 |
|
667 |
if(*temp==']') { |
668 |
push_sym(env, "["); |
669 |
pack(env); |
670 |
if(env->non_eval_flag) |
671 |
env->non_eval_flag--; |
672 |
break; |
673 |
} |
674 |
|
675 |
if(*temp=='[') { |
676 |
push_sym(env, "["); |
677 |
env->non_eval_flag++; |
678 |
break; |
679 |
} |
680 |
} |
681 |
} while(0); |
682 |
|
683 |
free(temp); |
684 |
|
685 |
if(convert<2) { |
686 |
free(rest); |
687 |
return; |
688 |
} |
689 |
|
690 |
stack_read(env, rest); |
691 |
|
692 |
free(rest); |
693 |
} |
694 |
|
695 |
/* Relocate elements of the list on the stack. */ |
696 |
extern void expand(environment *env) |
697 |
{ |
698 |
stackitem *temp, *new_head; |
699 |
|
700 |
/* Is top element a list? */ |
701 |
if(env->head==NULL) { |
702 |
printerr("Too Few Arguments"); |
703 |
env->err=1; |
704 |
return; |
705 |
} |
706 |
if(env->head->item->type!=list) { |
707 |
printerr("Bad Argument Type"); |
708 |
env->err=2; |
709 |
return; |
710 |
} |
711 |
|
712 |
rev(env); |
713 |
|
714 |
if(env->err) |
715 |
return; |
716 |
|
717 |
/* The first list element is the new stack head */ |
718 |
new_head= temp= env->head->item->content.ptr; |
719 |
|
720 |
env->head->item->refcount++; |
721 |
toss(env); |
722 |
|
723 |
/* Find the end of the list */ |
724 |
while(temp->next!=NULL) |
725 |
temp= temp->next; |
726 |
|
727 |
/* Connect the tail of the list with the old stack head */ |
728 |
temp->next= env->head; |
729 |
env->head= new_head; /* ...and voila! */ |
730 |
|
731 |
} |
732 |
|
733 |
/* Compares two elements by reference. */ |
734 |
extern void eq(environment *env) |
735 |
{ |
736 |
void *left, *right; |
737 |
int result; |
738 |
|
739 |
if((env->head)==NULL || env->head->next==NULL) { |
740 |
printerr("Too Few Arguments"); |
741 |
env->err=1; |
742 |
return; |
743 |
} |
744 |
|
745 |
left= env->head->item->content.ptr; |
746 |
swap(env); |
747 |
right= env->head->item->content.ptr; |
748 |
result= (left==right); |
749 |
|
750 |
toss(env); toss(env); |
751 |
push_int(&(env->head), result); |
752 |
} |
753 |
|
754 |
/* Negates the top element on the stack. */ |
755 |
extern void not(environment *env) |
756 |
{ |
757 |
int val; |
758 |
|
759 |
if((env->head)==NULL) { |
760 |
printerr("Too Few Arguments"); |
761 |
env->err=1; |
762 |
return; |
763 |
} |
764 |
|
765 |
if(env->head->item->type!=integer) { |
766 |
printerr("Bad Argument Type"); |
767 |
env->err=2; |
768 |
return; |
769 |
} |
770 |
|
771 |
val= env->head->item->content.val; |
772 |
toss(env); |
773 |
push_int(&(env->head), !val); |
774 |
} |
775 |
|
776 |
/* Compares the two top elements on the stack and return 0 if they're the |
777 |
same. */ |
778 |
extern void neq(environment *env) |
779 |
{ |
780 |
eq(env); |
781 |
not(env); |
782 |
} |
783 |
|
784 |
/* Give a symbol some content. */ |
785 |
extern void def(environment *env) |
786 |
{ |
787 |
symbol *sym; |
788 |
|
789 |
/* Needs two values on the stack, the top one must be a symbol */ |
790 |
if(env->head==NULL || env->head->next==NULL) { |
791 |
printerr("Too Few Arguments"); |
792 |
env->err=1; |
793 |
return; |
794 |
} |
795 |
|
796 |
if(env->head->item->type!=symb) { |
797 |
printerr("Bad Argument Type"); |
798 |
env->err=2; |
799 |
return; |
800 |
} |
801 |
|
802 |
/* long names are a pain */ |
803 |
sym=env->head->item->content.ptr; |
804 |
|
805 |
/* if the symbol was bound to something else, throw it away */ |
806 |
if(sym->val != NULL) |
807 |
free_val(sym->val); |
808 |
|
809 |
/* Bind the symbol to the value */ |
810 |
sym->val= env->head->next->item; |
811 |
sym->val->refcount++; /* Increase the reference counter */ |
812 |
|
813 |
toss(env); toss(env); |
814 |
} |
815 |
|
816 |
/* Quit stack. */ |
817 |
extern void quit(environment *env) |
818 |
{ |
819 |
exit(EXIT_SUCCESS); |
820 |
} |
821 |
|
822 |
/* Clear stack */ |
823 |
extern void clear(environment *env) |
824 |
{ |
825 |
while(env->head!=NULL) |
826 |
toss(env); |
827 |
} |
828 |
|
829 |
/* List all defined words */ |
830 |
extern void words(environment *env) |
831 |
{ |
832 |
symbol *temp; |
833 |
int i; |
834 |
|
835 |
for(i= 0; i<HASHTBLSIZE; i++) { |
836 |
temp= env->symbols[i]; |
837 |
while(temp!=NULL) { |
838 |
printf("%s\n", temp->id); |
839 |
temp= temp->next; |
840 |
} |
841 |
} |
842 |
} |
843 |
|
844 |
/* Forgets a symbol (remove it from the hash table) */ |
845 |
extern void forget(environment *env) |
846 |
{ |
847 |
char* sym_id; |
848 |
stackitem *stack_head= env->head; |
849 |
symbol **hash_entry, *temp; |
850 |
|
851 |
if(stack_head==NULL) { |
852 |
printerr("Too Few Arguments"); |
853 |
env->err=1; |
854 |
return; |
855 |
} |
856 |
|
857 |
if(stack_head->item->type!=symb) { |
858 |
printerr("Bad Argument Type"); |
859 |
env->err=2; |
860 |
return; |
861 |
} |
862 |
|
863 |
sym_id= ((symbol*)(stack_head->item->content.ptr))->id; |
864 |
toss(env); |
865 |
|
866 |
hash_entry= hash(env->symbols, sym_id); |
867 |
temp= *hash_entry; |
868 |
*hash_entry= (*hash_entry)->next; |
869 |
|
870 |
if(temp->val!=NULL) { |
871 |
free_val(temp->val); |
872 |
} |
873 |
free(temp->id); |
874 |
free(temp); |
875 |
} |
876 |
|
877 |
/* Returns the current error number to the stack */ |
878 |
extern void errn(environment *env){ |
879 |
push_int(&(env->head), env->err); |
880 |
} |
881 |
|
882 |
int main() |
883 |
{ |
884 |
environment myenv; |
885 |
char in_string[100]; |
886 |
|
887 |
init_env(&myenv); |
888 |
|
889 |
printf("okidok\n "); |
890 |
|
891 |
while(fgets(in_string, 100, stdin) != NULL) { |
892 |
stack_read(&myenv, in_string); |
893 |
if(myenv.err) { |
894 |
printf("(error %d) ", myenv.err); |
895 |
myenv.err=0; |
896 |
} |
897 |
printf("okidok\n "); |
898 |
} |
899 |
quit(&myenv); |
900 |
return EXIT_FAILURE; |
901 |
} |
902 |
|
903 |
/* + */ |
904 |
extern void sx_2b(environment *env) { |
905 |
int a, b; |
906 |
size_t len; |
907 |
char* new_string; |
908 |
value *a_val, *b_val; |
909 |
|
910 |
if((env->head)==NULL || env->head->next==NULL) { |
911 |
printerr("Too Few Arguments"); |
912 |
env->err=1; |
913 |
return; |
914 |
} |
915 |
|
916 |
if(env->head->item->type==string |
917 |
&& env->head->next->item->type==string) { |
918 |
a_val= env->head->item; |
919 |
b_val= env->head->next->item; |
920 |
a_val->refcount++; |
921 |
b_val->refcount++; |
922 |
toss(env); if(env->err) return; |
923 |
toss(env); if(env->err) return; |
924 |
len= strlen(a_val->content.ptr)+strlen(b_val->content.ptr)+1; |
925 |
new_string= malloc(len); |
926 |
strcpy(new_string, b_val->content.ptr); |
927 |
strcat(new_string, a_val->content.ptr); |
928 |
free_val(a_val); free_val(b_val); |
929 |
push_cstring(&(env->head), new_string); |
930 |
free(new_string); |
931 |
return; |
932 |
} |
933 |
|
934 |
if(env->head->item->type!=integer |
935 |
|| env->head->next->item->type!=integer) { |
936 |
printerr("Bad Argument Type"); |
937 |
env->err=2; |
938 |
return; |
939 |
} |
940 |
a=env->head->item->content.val; |
941 |
toss(env); |
942 |
if(env->err) return; |
943 |
b=env->head->item->content.val; |
944 |
toss(env); |
945 |
if(env->err) return; |
946 |
push_int(&(env->head), a+b); |
947 |
} |