cvs/stack/stack.c

/* printf */
#include <stdio.h>
/* EXIT_SUCCESS */
#include <stdlib.h>
/* NULL */
#include <stddef.h>
/* dlopen, dlsym, dlerror */
#include <dlfcn.h>
/* assert */
#include <assert.h>

#define HASHTBLSIZE 65536

typedef struct stack_item
{
  enum {
    value,                      /* Integer */
    string,
    ref,                        /* Reference (to an element in the
                                   hash table) */
    func,                       /* Function pointer */
    symbol, 
    list
  } type;                       /* Type of stack element */

  union {
    void* ptr;                  /* Pointer to the content */
    int val;                    /* ...or an integer */
  } content;                    /* Stores a pointer or an integer */

  char* id;                     /* Symbol name */
  struct stack_item* next;      /* Next element */
} stackitem;


typedef stackitem* hashtbl[HASHTBLSIZE]; /* Hash table declaration */
typedef void (*funcp)(stackitem**); /* funcp is a pointer to a
                                       void function (stackitem **) */

/* Initialize a newly created hash table. */
void init_hashtbl(hashtbl out_hash)
{
  long i;

  for(i= 0; i<HASHTBLSIZE; i++)
    out_hash[i]= NULL;
}

/* Returns a pointer to an element in the hash table. */
stackitem** hash(hashtbl in_hashtbl, const char* in_string)
{
  long i= 0;
  unsigned long out_hash= 0;
  char key= '\0';
  stackitem** position;
  
  while(1){                     /* Hash in_string */
    key= in_string[i++];
    if(key=='\0')
      break;
    out_hash= out_hash*32+key;
  }

  out_hash= out_hash%HASHTBLSIZE;
  position= &(in_hashtbl[out_hash]);

  while(position != NULL){
    if(*position==NULL)         /* If empty */
      return position;
    
    if(strcmp(in_string, (*position)->id)==0) /* If match */
      return position;

    position= &((*position)->next); /* Try next */
  }
  return NULL;                  /* end of list reached without finding
                                   an empty position */
}

/* Generic push function. */
int push(stackitem** stack_head, stackitem* in_item)
{
  in_item->next= *stack_head;
  *stack_head= in_item;
  return 1;
}

/* Push a value on the stack. */
int push_val(stackitem** stack_head, int in_val) 
{
  stackitem* new_item= malloc(sizeof(stackitem));
  assert(new_item != NULL);
  new_item->content.val= in_val;
  new_item->type= value;

  push(stack_head, new_item);
  return 1;
}

/* Copy a string onto the stack. */
int push_cstring(stackitem** stack_head, const char* in_string)
{
  stackitem* new_item= malloc(sizeof(stackitem));
  new_item->content.ptr= malloc(strlen(in_string)+1);
  strcpy(new_item->content.ptr, in_string);
  new_item->type= string;

  push(stack_head, new_item);
  return 1;
}

/* Create a new hash entry. */
int mk_hashentry(hashtbl in_hashtbl, stackitem* in_item, const char* id)
{
  in_item->id= malloc(strlen(id)+1);

  strcpy(in_item->id, id);
  push(hash(in_hashtbl, id), in_item);

  return 1;
}

/* Define a new function in the hash table. */
void def_func(hashtbl in_hashtbl, funcp in_func, const char* id)
{
  stackitem* temp= malloc(sizeof(stackitem));

  temp->type= func;
  temp->content.ptr= in_func;

  mk_hashentry(in_hashtbl, temp, id);
}

/* Define a new symbol in the hash table. */
void def_sym(hashtbl in_hashtbl, const char* id)
{
  stackitem* temp= malloc(sizeof(stackitem));
  
  temp->type= symbol;
  mk_hashentry(in_hashtbl, temp, id);
}

/* Push a reference to an entry in the hash table onto the stack. */
int push_ref(stackitem** stack_head, hashtbl in_hash, const char* in_string)
{
  static void* handle= NULL;
  void* symbol;

  stackitem* new_item= malloc(sizeof(stackitem));
  new_item->content.ptr= *hash(in_hash, in_string);
  new_item->type= ref;

  if(new_item->content.ptr==NULL) { /* If hash entry empty */
    if(handle==NULL)            /* If no handle */
      handle= dlopen(NULL, RTLD_LAZY);    

    symbol= dlsym(handle, in_string); /* Get function pointer */
    if(dlerror()==NULL)         /* If existing function pointer */
      def_func(in_hash, symbol, in_string); /* Store function pointer */
    else
      def_sym(in_hash, in_string); /* Make symbol */
      
    new_item->content.ptr= *hash(in_hash, in_string); /* XXX */
    new_item->type= ref;
  }

  push(stack_head, new_item);
  return 1;
}

void printerr(const char* in_string) {
  fprintf(stderr, "Err: %s\n", in_string);
}

/* Discard the top element of the stack. */
extern void toss(stackitem** stack_head)
{
  stackitem* temp= *stack_head;

  if((*stack_head)==NULL) {
    printerr("Stack empty");
    return;
  }
  
  if((*stack_head)->type==string)
    free((*stack_head)->content.ptr);

  *stack_head= (*stack_head)->next;
  free(temp);
}

/* Print newline. */
extern void nl()
{
  printf("\n");
}

/* Prints the top element of the stack. */
void print_(stackitem** stack_head)
{
  if((*stack_head)==NULL) {
    printerr("Stack empty");
    return;
  }

  switch((*stack_head)->type) {
  case value:
    printf("%d", (*stack_head)->content.val);
    break;
  case string:
    printf("%s", (char*)(*stack_head)->content.ptr);
    break;
  case ref:
    printf("%s", ((stackitem*)(*stack_head)->content.ptr)->id);
    break;
  case symbol:
  default:
    printf("%p", (*stack_head)->content.ptr);
    break;
  }
}

/* Prints the top element of the stack and then discards it. */
extern void print(stackitem** stack_head)
{
  print_(stack_head);
  toss(stack_head);
}

/* Only to be called by function printstack. */
void print_st(stackitem* stack_head, long counter)
{ 
  if(stack_head->next != NULL)
    print_st(stack_head->next, counter+1);

  printf("%ld: ", counter);
  print_(&stack_head);
  nl();
}

/* Prints the stack. */
extern void printstack(stackitem** stack_head)
{
  if(*stack_head != NULL) {
    print_st(*stack_head, 1);
    printf("\n");
  } else {
    printerr("Stack empty");
  }
}

/* If the top element is a reference, determine if it's a reference to a
   function, and if it is, toss the reference and execute the function. */
extern void eval(stackitem** stack_head)
{
  funcp in_func;

  if((*stack_head)==NULL || (*stack_head)->type!=ref) {
    printerr("Stack empty or not a reference");
    return;
  }

  if(((stackitem*)(*stack_head)->content.ptr)->type==func) {
    in_func= (funcp)((stackitem*)(*stack_head)->content.ptr)->content.ptr;
    toss(stack_head); 
    (*in_func)(stack_head);
    return;
  } else
    printerr("Not a function");
}

/* Make a list. */
extern void pack(stackitem** stack_head)
{
  void* delimiter;
  stackitem *iterator, *temp, *pack;

  if((*stack_head)==NULL) {
    printerr("Stack empty");
    return;
  }

  delimiter= (*stack_head)->content.ptr; /* Get delimiter */
  toss(stack_head);

  iterator= *stack_head;

  /* Search for first delimiter */
  while(iterator->next!=NULL && iterator->next->content.ptr!=delimiter)
    iterator= iterator->next;

  /* Extract list */
  temp= *stack_head;
  *stack_head= iterator->next;
  iterator->next= NULL;
  
  if(*stack_head!=NULL && (*stack_head)->content.ptr==delimiter)
    toss(stack_head);

  /* Push list */
  pack= malloc(sizeof(stackitem));
  pack->type= list;
  pack->content.ptr= temp;

  push(stack_head, pack);
}

/* Parse input. */
int stack_read(stackitem** stack_head, hashtbl in_hash, char* in_line) 
{
  char *temp, *rest;
  int itemp;
  size_t inlength= strlen(in_line)+1;
  int convert= 0;
  static int non_eval_flag= 0;

  temp= malloc(inlength);
  rest= malloc(inlength);

  do {
    /* If string */
    if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest))) {
      push_cstring(stack_head, temp);
      break;
    }
    /* If value */
    if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest))) {
      push_val(stack_head, itemp);
      break;
    }
    /* Escape ';' with '\' */
    if((convert= sscanf(in_line, "\\%c%[^\n\r]", temp, rest))) {
      temp[1]= '\0'; 
      push_ref(stack_head, in_hash, temp);
      break;
    } 
    /* If symbol */
    if((convert= sscanf(in_line, "%[^] ;\n\r]%[^\n\r]", temp, rest))) {
        push_ref(stack_head, in_hash, temp);
        break;
    }
    /* If single char */
    if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest))) {
      if(*temp==';') {
        if(non_eval_flag) {
          eval(stack_head);             /* Evaluate top element */
          break;
        }
        
        push_ref(stack_head, in_hash, ";");
        break;
      }

      if(*temp==']') {
        push_ref(stack_head, in_hash, "[");
        pack(stack_head);
        non_eval_flag--;
        break;
      }

      if(*temp=='[') {
        push_ref(stack_head, in_hash, "[");
        non_eval_flag++;
        break;
      }
    }
  } while(0);


  free(temp);

  if(convert<2) {
    free(rest);
    return 0;
  }
   
  stack_read(stack_head, in_hash, rest);
  
  free(rest);
  return 1;
}

/* Relocate elements of the list on the stack. */
extern void expand(stackitem** stack_head)
{
  stackitem *temp, *new_head;

  /* Is top element a list? */
  if((*stack_head)==NULL || (*stack_head)->type!=list) {
    printerr("Stack empty or not a list");
    return;
  }

  /* The first list element is the new stack head */
  new_head= temp= (*stack_head)->content.ptr;
  toss(stack_head);

  /* Search the end of the list */
  while(temp->next!=NULL)
    temp= temp->next;

  /* Connect the the tail of the list with the old stack head */
  temp->next= *stack_head;
  *stack_head= new_head;        /* ...and voila! */
}

/* Swap the two top elements on the stack. */
extern void swap(stackitem** stack_head)
{
  stackitem* temp= (*stack_head);
  
  if((*stack_head)==NULL) {
    printerr("Stack empty");
    return;
  }

  if((*stack_head)->next==NULL)
    return;

  *stack_head= (*stack_head)->next;
  temp->next= (*stack_head)->next;
  (*stack_head)->next= temp;
} 

/* Compares two elements by reference. */
extern void eq(stackitem** stack_head)
{
  void *left, *right;
  int result;

  if((*stack_head)==NULL || (*stack_head)->next==NULL) {
    printerr("Not enough elements to compare");
    return;
  }

  left= (*stack_head)->content.ptr;
  swap(stack_head);
  right= (*stack_head)->content.ptr;
  result= (left==right);
  
  toss(stack_head); toss(stack_head);
  push_val(stack_head, (left==right));
}

/* Negates the top element on the stack. */
extern void not(stackitem** stack_head)
{
  int value;

  if((*stack_head)==NULL || (*stack_head)->type!=value) {
    printerr("Stack empty or element is not a value");
    return;
  }

  value= (*stack_head)->content.val;
  toss(stack_head);
  push_val(stack_head, !value);
}

/* Compares the two top elements on the stack and return 0 if they're the
   same. */
extern void neq(stackitem** stack_head)
{
  eq(stack_head);
  not(stack_head);
}

/* Give a symbol some content. */
extern void def(stackitem** stack_head)
{
  stackitem *temp, *value;

  if(*stack_head==NULL || (*stack_head)->next==NULL 
     || (*stack_head)->type!=ref) {
    printerr("Define what?");
    return;
  }

  temp= (*stack_head)->content.ptr;
  value= (*stack_head)->next;
  temp->content= value->content;
  value->content.ptr=NULL;
  temp->type= value->type;

  toss(stack_head); toss(stack_head);
} 

/* Quit stack. */
extern void quit()
{
  exit(EXIT_SUCCESS);
}

int main()
{
  stackitem* s= NULL;
  hashtbl myhash;
  char in_string[100];

  init_hashtbl(myhash);

  printf("okidok\n ");

  while(fgets(in_string, 100, stdin) != NULL) {
    stack_read(&s, myhash, in_string);
    printf("okidok\n ");
  }

  exit(EXIT_SUCCESS);
}

/* Local Variables: */
/* compile-command:"make CFLAGS=\"-Wall -g -rdynamic -ldl\" stack" */
/* End: */
1	masse	1.1	/* printf */
2			#include <stdio.h>
3			/* EXIT_SUCCESS */
4			#include <stdlib.h>
5			/* NULL */
6			#include <stddef.h>
7	teddy	1.3	/* dlopen, dlsym, dlerror */
8	masse	1.1	#include <dlfcn.h>
9	teddy	1.18	/* assert */
10			#include <assert.h>
11	masse	1.1
12			#define HASHTBLSIZE 65536
13
14			typedef struct stack_item
15			{
16	masse	1.16	enum {
17			value, /* Integer */
18	teddy	1.18	string,
19			ref, /* Reference (to an element in the
20			hash table) */
21	masse	1.16	func, /* Function pointer */
22			symbol,
23			list
24	teddy	1.18	} type; /* Type of stack element */
25
26	masse	1.1	union {
27	masse	1.16	void* ptr; /* Pointer to the content */
28			int val; /* ...or an integer */
29			} content; /* Stores a pointer or an integer */
30	masse	1.1
31	masse	1.16	char* id; /* Symbol name */
32			struct stack_item* next; /* Next element */
33	masse	1.1	} stackitem;
34
35
36	masse	1.16	typedef stackitem* hashtbl[HASHTBLSIZE]; /* Hash table declaration */
37	teddy	1.18	typedef void (funcp)(stackitem); / funcp is a pointer to a
38			void function (stackitem *) /
39	masse	1.14
40	teddy	1.18	/* Initialize a newly created hash table. */
41	masse	1.1	void init_hashtbl(hashtbl out_hash)
42			{
43			long i;
44
45			for(i= 0; i<HASHTBLSIZE; i++)
46			out_hash[i]= NULL;
47			}
48
49	masse	1.14	/* Returns a pointer to an element in the hash table. */
50	masse	1.1	stackitem** hash(hashtbl in_hashtbl, const char* in_string)
51			{
52			long i= 0;
53			unsigned long out_hash= 0;
54	teddy	1.18	char key= '\0';
55	masse	1.1	stackitem** position;
56
57	masse	1.16	while(1){ /* Hash in_string */
58	masse	1.1	key= in_string[i++];
59			if(key=='\0')
60			break;
61			out_hash= out_hash*32+key;
62			}
63
64			out_hash= out_hash%HASHTBLSIZE;
65			position= &(in_hashtbl[out_hash]);
66
67	teddy	1.18	while(position != NULL){
68			if(position==NULL) / If empty */
69	masse	1.1	return position;
70
71	teddy	1.18	if(strcmp(in_string, (position)->id)==0) / If match */
72	masse	1.1	return position;
73
74	masse	1.16	position= &((position)->next); / Try next */
75	masse	1.1	}
76	teddy	1.18	return NULL; /* end of list reached without finding
77			an empty position */
78	masse	1.1	}
79
80	masse	1.14	/* Generic push function. */
81	masse	1.1	int push(stackitem** stack_head, stackitem* in_item)
82			{
83			in_item->next= *stack_head;
84			*stack_head= in_item;
85			return 1;
86			}
87
88	masse	1.14	/* Push a value on the stack. */
89	masse	1.1	int push_val(stackitem** stack_head, int in_val)
90			{
91			stackitem* new_item= malloc(sizeof(stackitem));
92	teddy	1.18	assert(new_item != NULL);
93	masse	1.1	new_item->content.val= in_val;
94			new_item->type= value;
95
96			push(stack_head, new_item);
97			return 1;
98			}
99
100	masse	1.14	/* Copy a string onto the stack. */
101	masse	1.1	int push_cstring(stackitem** stack_head, const char* in_string)
102			{
103			stackitem* new_item= malloc(sizeof(stackitem));
104			new_item->content.ptr= malloc(strlen(in_string)+1);
105			strcpy(new_item->content.ptr, in_string);
106			new_item->type= string;
107
108			push(stack_head, new_item);
109			return 1;
110			}
111
112	masse	1.14	/* Create a new hash entry. */
113	masse	1.1	int mk_hashentry(hashtbl in_hashtbl, stackitem* in_item, const char* id)
114			{
115			in_item->id= malloc(strlen(id)+1);
116
117			strcpy(in_item->id, id);
118			push(hash(in_hashtbl, id), in_item);
119
120			return 1;
121			}
122
123	teddy	1.18	/* Define a new function in the hash table. */
124	masse	1.1	void def_func(hashtbl in_hashtbl, funcp in_func, const char* id)
125			{
126			stackitem* temp= malloc(sizeof(stackitem));
127
128			temp->type= func;
129			temp->content.ptr= in_func;
130
131			mk_hashentry(in_hashtbl, temp, id);
132			}
133
134	masse	1.14	/* Define a new symbol in the hash table. */
135	masse	1.4	void def_sym(hashtbl in_hashtbl, const char* id)
136			{
137			stackitem* temp= malloc(sizeof(stackitem));
138
139			temp->type= symbol;
140			mk_hashentry(in_hashtbl, temp, id);
141			}
142
143	masse	1.14	/* Push a reference to an entry in the hash table onto the stack. */
144	masse	1.1	int push_ref(stackitem** stack_head, hashtbl in_hash, const char* in_string)
145			{
146	masse	1.6	static void* handle= NULL;
147	masse	1.1	void* symbol;
148	masse	1.6
149	masse	1.1	stackitem* new_item= malloc(sizeof(stackitem));
150			new_item->content.ptr= *hash(in_hash, in_string);
151			new_item->type= ref;
152
153	masse	1.16	if(new_item->content.ptr==NULL) { /* If hash entry empty */
154			if(handle==NULL) /* If no handle */
155	masse	1.9	handle= dlopen(NULL, RTLD_LAZY);
156	masse	1.6
157	masse	1.16	symbol= dlsym(handle, in_string); /* Get function pointer */
158			if(dlerror()==NULL) /* If existing function pointer */
159			def_func(in_hash, symbol, in_string); /* Store function pointer */
160	masse	1.4	else
161	masse	1.16	def_sym(in_hash, in_string); /* Make symbol */
162	masse	1.4
163	masse	1.16	new_item->content.ptr= hash(in_hash, in_string); / XXX */
164	masse	1.4	new_item->type= ref;
165	masse	1.1	}
166
167			push(stack_head, new_item);
168			return 1;
169			}
170
171	masse	1.17	void printerr(const char* in_string) {
172			fprintf(stderr, "Err: %s\n", in_string);
173			}
174
175	masse	1.14	/* Discard the top element of the stack. */
176	masse	1.1	extern void toss(stackitem** stack_head)
177			{
178			stackitem* temp= *stack_head;
179
180	masse	1.17	if((*stack_head)==NULL) {
181			printerr("Stack empty");
182	masse	1.7	return;
183	masse	1.17	}
184	masse	1.7
185			if((*stack_head)->type==string)
186			free((*stack_head)->content.ptr);
187
188	masse	1.1	stack_head= (stack_head)->next;
189			free(temp);
190			}
191
192	masse	1.14	/* Print newline. */
193	masse	1.8	extern void nl()
194			{
195			printf("\n");
196			}
197	masse	1.1
198	masse	1.14	/* Prints the top element of the stack. */
199	masse	1.11	void print_(stackitem** stack_head)
200	masse	1.8	{
201	masse	1.17	if((*stack_head)==NULL) {
202			printerr("Stack empty");
203	masse	1.8	return;
204	masse	1.17	}
205	masse	1.1
206	masse	1.8	switch((*stack_head)->type) {
207	teddy	1.2	case value:
208	masse	1.8	printf("%d", (*stack_head)->content.val);
209	teddy	1.2	break;
210			case string:
211	masse	1.8	printf("%s", (char)(stack_head)->content.ptr);
212	teddy	1.2	break;
213			case ref:
214	masse	1.8	printf("%s", ((stackitem)(stack_head)->content.ptr)->id);
215	masse	1.6	break;
216	masse	1.4	case symbol:
217	masse	1.7	default:
218	masse	1.8	printf("%p", (*stack_head)->content.ptr);
219	teddy	1.2	break;
220			}
221	masse	1.1	}
222
223	masse	1.14	/* Prints the top element of the stack and then discards it. */
224	masse	1.8	extern void print(stackitem** stack_head)
225			{
226	masse	1.11	print_(stack_head);
227	masse	1.8	toss(stack_head);
228			}
229
230	masse	1.14	/* Only to be called by function printstack. */
231	masse	1.8	void print_st(stackitem* stack_head, long counter)
232			{
233			if(stack_head->next != NULL)
234			print_st(stack_head->next, counter+1);
235
236			printf("%ld: ", counter);
237	masse	1.11	print_(&stack_head);
238	masse	1.8	nl();
239			}
240
241	masse	1.14	/* Prints the stack. */
242	masse	1.1	extern void printstack(stackitem** stack_head)
243			{
244			if(*stack_head != NULL) {
245			print_st(*stack_head, 1);
246			printf("\n");
247	masse	1.17	} else {
248			printerr("Stack empty");
249	masse	1.1	}
250			}
251
252	masse	1.14	/* If the top element is a reference, determine if it's a reference to a
253	masse	1.16	function, and if it is, toss the reference and execute the function. */
254	masse	1.1	extern void eval(stackitem** stack_head)
255			{
256			funcp in_func;
257
258	masse	1.17	if((stack_head)==NULL \|\| (stack_head)->type!=ref) {
259			printerr("Stack empty or not a reference");
260	masse	1.1	return;
261	masse	1.17	}
262	masse	1.1
263			if(((stackitem)(stack_head)->content.ptr)->type==func) {
264			in_func= (funcp)((stackitem)(stack_head)->content.ptr)->content.ptr;
265			toss(stack_head);
266			(*in_func)(stack_head);
267			return;
268	masse	1.17	} else
269			printerr("Not a function");
270	masse	1.1	}
271
272	masse	1.19	/* Make a list. */
273			extern void pack(stackitem** stack_head)
274			{
275			void* delimiter;
276			stackitem iterator, temp, *pack;
277
278			if((*stack_head)==NULL) {
279			printerr("Stack empty");
280			return;
281			}
282
283			delimiter= (stack_head)->content.ptr; / Get delimiter */
284			toss(stack_head);
285
286			iterator= *stack_head;
287
288			/* Search for first delimiter */
289			while(iterator->next!=NULL && iterator->next->content.ptr!=delimiter)
290			iterator= iterator->next;
291
292			/* Extract list */
293			temp= *stack_head;
294			*stack_head= iterator->next;
295			iterator->next= NULL;
296
297			if(stack_head!=NULL && (stack_head)->content.ptr==delimiter)
298			toss(stack_head);
299
300			/* Push list */
301			pack= malloc(sizeof(stackitem));
302			pack->type= list;
303			pack->content.ptr= temp;
304
305			push(stack_head, pack);
306			}
307
308	masse	1.14	/* Parse input. */
309	masse	1.1	int stack_read(stackitem** stack_head, hashtbl in_hash, char* in_line)
310			{
311			char temp, rest;
312			int itemp;
313			size_t inlength= strlen(in_line)+1;
314			int convert= 0;
315	masse	1.20	static int non_eval_flag= 0;
316	masse	1.1
317			temp= malloc(inlength);
318			rest= malloc(inlength);
319
320	masse	1.15	do {
321	masse	1.16	/* If string */
322	masse	1.15	if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest))) {
323			push_cstring(stack_head, temp);
324			break;
325			}
326	masse	1.16	/* If value */
327	masse	1.15	if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest))) {
328			push_val(stack_head, itemp);
329			break;
330			}
331	masse	1.16	/* Escape ';' with '\' */
332	masse	1.15	if((convert= sscanf(in_line, "\\%c%[^\n\r]", temp, rest))) {
333			temp[1]= '\0';
334			push_ref(stack_head, in_hash, temp);
335			break;
336			}
337	masse	1.16	/* If symbol */
338	masse	1.19	if((convert= sscanf(in_line, "%[^] ;\n\r]%[^\n\r]", temp, rest))) {
339	masse	1.15	push_ref(stack_head, in_hash, temp);
340			break;
341			}
342	masse	1.19	/* If single char */
343			if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest))) {
344			if(*temp==';') {
345	masse	1.20	if(non_eval_flag) {
346			eval(stack_head); /* Evaluate top element */
347			break;
348			}
349
350			push_ref(stack_head, in_hash, ";");
351	masse	1.19	break;
352			}
353
354			if(*temp==']') {
355			push_ref(stack_head, in_hash, "[");
356			pack(stack_head);
357	masse	1.20	non_eval_flag--;
358			break;
359			}
360
361			if(*temp=='[') {
362			push_ref(stack_head, in_hash, "[");
363			non_eval_flag++;
364	masse	1.19	break;
365			}
366	masse	1.15	}
367			} while(0);
368
369	masse	1.1
370			free(temp);
371
372			if(convert<2) {
373			free(rest);
374			return 0;
375			}
376
377			stack_read(stack_head, in_hash, rest);
378
379			free(rest);
380			return 1;
381	masse	1.7	}
382	masse	1.1
383	masse	1.16	/* Relocate elements of the list on the stack. */
384	masse	1.8	extern void expand(stackitem** stack_head)
385	masse	1.1	{
386	masse	1.8	stackitem temp, new_head;
387
388	masse	1.16	/* Is top element a list? */
389	masse	1.17	if((stack_head)==NULL \|\| (stack_head)->type!=list) {
390			printerr("Stack empty or not a list");
391	masse	1.8	return;
392	masse	1.17	}
393	masse	1.8
394	masse	1.16	/* The first list element is the new stack head */
395	masse	1.8	new_head= temp= (*stack_head)->content.ptr;
396			toss(stack_head);
397
398	masse	1.16	/* Search the end of the list */
399	masse	1.8	while(temp->next!=NULL)
400			temp= temp->next;
401
402	masse	1.16	/* Connect the the tail of the list with the old stack head */
403	masse	1.8	temp->next= *stack_head;
404	masse	1.16	stack_head= new_head; / ...and voila! */
405	teddy	1.5	}
406
407	masse	1.14	/* Swap the two top elements on the stack. */
408	masse	1.10	extern void swap(stackitem** stack_head)
409			{
410			stackitem* temp= (*stack_head);
411
412	masse	1.17	if((*stack_head)==NULL) {
413			printerr("Stack empty");
414			return;
415			}
416
417			if((*stack_head)->next==NULL)
418	masse	1.10	return;
419
420			stack_head= (stack_head)->next;
421			temp->next= (*stack_head)->next;
422			(*stack_head)->next= temp;
423			}
424	masse	1.11
425	masse	1.14	/* Compares two elements by reference. */
426	masse	1.11	extern void eq(stackitem** stack_head)
427			{
428			void left, right;
429			int result;
430
431	masse	1.17	if((stack_head)==NULL \|\| (stack_head)->next==NULL) {
432			printerr("Not enough elements to compare");
433	masse	1.11	return;
434	masse	1.17	}
435	masse	1.11
436			left= (*stack_head)->content.ptr;
437	masse	1.12	swap(stack_head);
438			right= (*stack_head)->content.ptr;
439	masse	1.11	result= (left==right);
440
441			toss(stack_head); toss(stack_head);
442			push_val(stack_head, (left==right));
443			}
444
445	masse	1.14	/* Negates the top element on the stack. */
446	masse	1.11	extern void not(stackitem** stack_head)
447			{
448			int value;
449
450	masse	1.17	if((stack_head)==NULL \|\| (stack_head)->type!=value) {
451			printerr("Stack empty or element is not a value");
452	masse	1.11	return;
453	masse	1.17	}
454	masse	1.11
455			value= (*stack_head)->content.val;
456			toss(stack_head);
457			push_val(stack_head, !value);
458			}
459
460	masse	1.14	/* Compares the two top elements on the stack and return 0 if they're the
461			same. */
462	masse	1.11	extern void neq(stackitem** stack_head)
463			{
464			eq(stack_head);
465			not(stack_head);
466			}
467	masse	1.12
468	masse	1.14	/* Give a symbol some content. */
469	masse	1.12	extern void def(stackitem** stack_head)
470			{
471			stackitem temp, value;
472
473			if(stack_head==NULL \|\| (stack_head)->next==NULL
474	masse	1.17	\|\| (*stack_head)->type!=ref) {
475			printerr("Define what?");
476	masse	1.12	return;
477	masse	1.17	}
478	masse	1.12
479			temp= (*stack_head)->content.ptr;
480			value= (*stack_head)->next;
481			temp->content= value->content;
482			value->content.ptr=NULL;
483			temp->type= value->type;
484
485			toss(stack_head); toss(stack_head);
486			}
487	masse	1.10
488	masse	1.14	/* Quit stack. */
489	teddy	1.5	extern void quit()
490			{
491			exit(EXIT_SUCCESS);
492	masse	1.1	}
493
494			int main()
495			{
496			stackitem* s= NULL;
497			hashtbl myhash;
498			char in_string[100];
499
500			init_hashtbl(myhash);
501
502			printf("okidok\n ");
503
504			while(fgets(in_string, 100, stdin) != NULL) {
505			stack_read(&s, myhash, in_string);
506			printf("okidok\n ");
507			}
508
509	masse	1.10	exit(EXIT_SUCCESS);
510	masse	1.1	}
511	teddy	1.3
512			/* Local Variables: */
513			/* compile-command:"make CFLAGS=\"-Wall -g -rdynamic -ldl\" stack" */
514			/* End: */