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(1){
    if(*position==NULL)         /* If empty */
      return position;
    
    if(strcmp(in_string, (*position)->id)==0) /* If match */
      return position;

    position= &((*position)->next); /* Try next */
  }
}

/* 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); /* The new reference 
                                                         shouldn't point at 
                                                         NULL */
    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. */
extern void print_(stackitem** stack_head)
{
  stackitem* temp= *stack_head;

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

  while(temp->type==ref) {
    temp= temp->content.ptr;

    if(temp->type!=ref) {
      printf("ref-> %s", temp->id);
      return;
    }
  }

  switch(temp->type) {
  case value:
    printf("%d", temp->content.val);
    break;
  case string:
    printf("\"%s\"", (char*)temp->content.ptr);
    break;
  case symbol:
  case func:
    printf("%s", temp->id);
    break;
  default:
    printf("%p", temp->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);
    nl();
  } else {
    printerr("Stack empty");
  }
}

/* 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;
} 

stackitem* copy(stackitem* in_item)
{
  stackitem* out_item= malloc(sizeof(stackitem));

  memcpy(out_item, in_item, sizeof(stackitem));
  out_item->next= NULL;

  return out_item;
}


/* 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;
  stackitem* temp= *stack_head;

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

  while(temp->type==ref)
    temp= temp->content.ptr;

  if(temp->type==func) {
    in_func= (funcp)(temp->content.ptr);
    toss(stack_head); 
    (*in_func)(stack_head);
    return;
  }

  push(stack_head, copy(temp));
  swap(stack_head);
  toss(stack_head);
}

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

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

  iterator= *stack_head;

  if(iterator==NULL || iterator->content.ptr==delimiter) {
    temp= NULL;
    toss(stack_head);
  } else {
    /* 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);
        if(non_eval_flag!=0)
          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);

  if(temp==NULL)
    return;

  /* 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! */
}

/* 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);
}

/* Clear stack */
extern void clear(stackitem** stack_head)
{
  while(*stack_head!=NULL)
    toss(stack_head);
}

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	masse	1.25	while(1){
68	teddy	1.18	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			}
77
78	masse	1.14	/* Generic push function. */
79	masse	1.1	int push(stackitem** stack_head, stackitem* in_item)
80			{
81			in_item->next= *stack_head;
82			*stack_head= in_item;
83			return 1;
84			}
85
86	masse	1.14	/* Push a value on the stack. */
87	masse	1.1	int push_val(stackitem** stack_head, int in_val)
88			{
89			stackitem* new_item= malloc(sizeof(stackitem));
90	teddy	1.18	assert(new_item != NULL);
91	masse	1.1	new_item->content.val= in_val;
92			new_item->type= value;
93
94			push(stack_head, new_item);
95			return 1;
96			}
97
98	masse	1.14	/* Copy a string onto the stack. */
99	masse	1.1	int push_cstring(stackitem** stack_head, const char* in_string)
100			{
101			stackitem* new_item= malloc(sizeof(stackitem));
102			new_item->content.ptr= malloc(strlen(in_string)+1);
103			strcpy(new_item->content.ptr, in_string);
104			new_item->type= string;
105
106			push(stack_head, new_item);
107			return 1;
108			}
109
110	masse	1.14	/* Create a new hash entry. */
111	masse	1.1	int mk_hashentry(hashtbl in_hashtbl, stackitem* in_item, const char* id)
112			{
113			in_item->id= malloc(strlen(id)+1);
114
115			strcpy(in_item->id, id);
116			push(hash(in_hashtbl, id), in_item);
117
118			return 1;
119			}
120
121	teddy	1.18	/* Define a new function in the hash table. */
122	masse	1.1	void def_func(hashtbl in_hashtbl, funcp in_func, const char* id)
123			{
124			stackitem* temp= malloc(sizeof(stackitem));
125
126			temp->type= func;
127			temp->content.ptr= in_func;
128
129			mk_hashentry(in_hashtbl, temp, id);
130			}
131
132	masse	1.14	/* Define a new symbol in the hash table. */
133	masse	1.4	void def_sym(hashtbl in_hashtbl, const char* id)
134			{
135			stackitem* temp= malloc(sizeof(stackitem));
136
137			temp->type= symbol;
138			mk_hashentry(in_hashtbl, temp, id);
139			}
140
141	masse	1.14	/* Push a reference to an entry in the hash table onto the stack. */
142	masse	1.1	int push_ref(stackitem** stack_head, hashtbl in_hash, const char* in_string)
143			{
144	masse	1.6	static void* handle= NULL;
145	masse	1.1	void* symbol;
146	masse	1.6
147	masse	1.1	stackitem* new_item= malloc(sizeof(stackitem));
148			new_item->content.ptr= *hash(in_hash, in_string);
149			new_item->type= ref;
150
151	masse	1.16	if(new_item->content.ptr==NULL) { /* If hash entry empty */
152			if(handle==NULL) /* If no handle */
153	masse	1.9	handle= dlopen(NULL, RTLD_LAZY);
154	masse	1.6
155	masse	1.16	symbol= dlsym(handle, in_string); /* Get function pointer */
156			if(dlerror()==NULL) /* If existing function pointer */
157			def_func(in_hash, symbol, in_string); /* Store function pointer */
158	masse	1.4	else
159	masse	1.16	def_sym(in_hash, in_string); /* Make symbol */
160	masse	1.4
161	masse	1.23	new_item->content.ptr= hash(in_hash, in_string); / The new reference
162			shouldn't point at
163			NULL */
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	1.23	extern void print_(stackitem** stack_head)
200	masse	1.8	{
201	masse	1.23	stackitem* temp= *stack_head;
202
203			if(temp==NULL) {
204	masse	1.17	printerr("Stack empty");
205	masse	1.8	return;
206	masse	1.17	}
207	masse	1.1
208	masse	1.26	while(temp->type==ref) {
209	masse	1.23	temp= temp->content.ptr;
210
211	masse	1.26	if(temp->type!=ref) {
212			printf("ref-> %s", temp->id);
213			return;
214			}
215			}
216
217	masse	1.23	switch(temp->type) {
218	teddy	1.2	case value:
219	masse	1.23	printf("%d", temp->content.val);
220	teddy	1.2	break;
221			case string:
222	masse	1.23	printf("\"%s\"", (char*)temp->content.ptr);
223	teddy	1.2	break;
224	masse	1.23	case symbol:
225	masse	1.25	case func:
226	masse	1.23	printf("%s", temp->id);
227	masse	1.6	break;
228	masse	1.7	default:
229	masse	1.23	printf("%p", temp->content.ptr);
230	teddy	1.2	break;
231			}
232	masse	1.1	}
233
234	masse	1.14	/* Prints the top element of the stack and then discards it. */
235	masse	1.8	extern void print(stackitem** stack_head)
236			{
237	masse	1.11	print_(stack_head);
238	masse	1.8	toss(stack_head);
239			}
240
241	masse	1.14	/* Only to be called by function printstack. */
242	masse	1.8	void print_st(stackitem* stack_head, long counter)
243			{
244			if(stack_head->next != NULL)
245			print_st(stack_head->next, counter+1);
246
247			printf("%ld: ", counter);
248	masse	1.11	print_(&stack_head);
249	masse	1.8	nl();
250			}
251
252	masse	1.14	/* Prints the stack. */
253	masse	1.1	extern void printstack(stackitem** stack_head)
254			{
255			if(*stack_head != NULL) {
256			print_st(*stack_head, 1);
257	masse	1.21	nl();
258	masse	1.17	} else {
259			printerr("Stack empty");
260	masse	1.1	}
261			}
262
263	masse	1.26	/* Swap the two top elements on the stack. */
264			extern void swap(stackitem** stack_head)
265			{
266			stackitem* temp= (*stack_head);
267
268			if((*stack_head)==NULL) {
269			printerr("Stack empty");
270			return;
271			}
272
273			if((*stack_head)->next==NULL)
274			return;
275
276			stack_head= (stack_head)->next;
277			temp->next= (*stack_head)->next;
278			(*stack_head)->next= temp;
279			}
280
281			stackitem* copy(stackitem* in_item)
282			{
283			stackitem* out_item= malloc(sizeof(stackitem));
284
285			memcpy(out_item, in_item, sizeof(stackitem));
286			out_item->next= NULL;
287
288			return out_item;
289			}
290
291
292	masse	1.14	/* If the top element is a reference, determine if it's a reference to a
293	masse	1.16	function, and if it is, toss the reference and execute the function. */
294	masse	1.1	extern void eval(stackitem** stack_head)
295			{
296			funcp in_func;
297	masse	1.22	stackitem* temp= *stack_head;
298	masse	1.1
299	masse	1.22	if(temp==NULL) {
300			printerr("Stack empty");
301	masse	1.1	return;
302	masse	1.17	}
303	masse	1.1
304	masse	1.22	while(temp->type==ref)
305			temp= temp->content.ptr;
306
307			if(temp->type==func) {
308			in_func= (funcp)(temp->content.ptr);
309	masse	1.1	toss(stack_head);
310			(*in_func)(stack_head);
311			return;
312	masse	1.26	}
313
314			push(stack_head, copy(temp));
315			swap(stack_head);
316			toss(stack_head);
317	masse	1.1	}
318
319	masse	1.19	/* Make a list. */
320			extern void pack(stackitem** stack_head)
321			{
322			void* delimiter;
323			stackitem iterator, temp, *pack;
324
325			delimiter= (stack_head)->content.ptr; / Get delimiter */
326			toss(stack_head);
327
328			iterator= *stack_head;
329
330	masse	1.24	if(iterator==NULL \|\| iterator->content.ptr==delimiter) {
331			temp= NULL;
332	masse	1.19	toss(stack_head);
333	masse	1.24	} else {
334			/* Search for first delimiter */
335			while(iterator->next!=NULL && iterator->next->content.ptr!=delimiter)
336			iterator= iterator->next;
337
338			/* Extract list */
339			temp= *stack_head;
340			*stack_head= iterator->next;
341			iterator->next= NULL;
342
343			if(stack_head!=NULL && (stack_head)->content.ptr==delimiter)
344			toss(stack_head);
345			}
346	masse	1.19
347			/* Push list */
348			pack= malloc(sizeof(stackitem));
349			pack->type= list;
350			pack->content.ptr= temp;
351
352			push(stack_head, pack);
353			}
354
355	masse	1.14	/* Parse input. */
356	masse	1.1	int stack_read(stackitem** stack_head, hashtbl in_hash, char* in_line)
357			{
358			char temp, rest;
359			int itemp;
360			size_t inlength= strlen(in_line)+1;
361			int convert= 0;
362	masse	1.20	static int non_eval_flag= 0;
363	masse	1.1
364			temp= malloc(inlength);
365			rest= malloc(inlength);
366
367	masse	1.15	do {
368	masse	1.16	/* If string */
369	masse	1.15	if((convert= sscanf(in_line, "\"%[^\"\n\r]\" %[^\n\r]", temp, rest))) {
370			push_cstring(stack_head, temp);
371			break;
372			}
373	masse	1.16	/* If value */
374	masse	1.15	if((convert= sscanf(in_line, "%d %[^\n\r]", &itemp, rest))) {
375			push_val(stack_head, itemp);
376			break;
377			}
378	masse	1.16	/* Escape ';' with '\' */
379	masse	1.15	if((convert= sscanf(in_line, "\\%c%[^\n\r]", temp, rest))) {
380			temp[1]= '\0';
381			push_ref(stack_head, in_hash, temp);
382			break;
383			}
384	masse	1.16	/* If symbol */
385	masse	1.21	if((convert= sscanf(in_line, "%[^][ ;\n\r]%[^\n\r]", temp, rest))) {
386	masse	1.15	push_ref(stack_head, in_hash, temp);
387			break;
388			}
389	masse	1.19	/* If single char */
390			if((convert= sscanf(in_line, "%c%[^\n\r]", temp, rest))) {
391			if(*temp==';') {
392	masse	1.21	if(!non_eval_flag) {
393	masse	1.20	eval(stack_head); /* Evaluate top element */
394			break;
395			}
396
397			push_ref(stack_head, in_hash, ";");
398	masse	1.19	break;
399			}
400
401			if(*temp==']') {
402			push_ref(stack_head, in_hash, "[");
403			pack(stack_head);
404	masse	1.21	if(non_eval_flag!=0)
405			non_eval_flag--;
406	masse	1.20	break;
407			}
408
409			if(*temp=='[') {
410			push_ref(stack_head, in_hash, "[");
411			non_eval_flag++;
412	masse	1.19	break;
413			}
414	masse	1.15	}
415			} while(0);
416
417	masse	1.1
418			free(temp);
419
420			if(convert<2) {
421			free(rest);
422			return 0;
423			}
424
425			stack_read(stack_head, in_hash, rest);
426
427			free(rest);
428			return 1;
429	masse	1.7	}
430	masse	1.1
431	masse	1.16	/* Relocate elements of the list on the stack. */
432	masse	1.8	extern void expand(stackitem** stack_head)
433	masse	1.1	{
434	masse	1.8	stackitem temp, new_head;
435
436	masse	1.16	/* Is top element a list? */
437	masse	1.17	if((stack_head)==NULL \|\| (stack_head)->type!=list) {
438			printerr("Stack empty or not a list");
439	masse	1.8	return;
440	masse	1.17	}
441	masse	1.8
442	masse	1.16	/* The first list element is the new stack head */
443	masse	1.8	new_head= temp= (*stack_head)->content.ptr;
444			toss(stack_head);
445
446	masse	1.24	if(temp==NULL)
447			return;
448
449	masse	1.16	/* Search the end of the list */
450	masse	1.8	while(temp->next!=NULL)
451			temp= temp->next;
452
453	masse	1.16	/* Connect the the tail of the list with the old stack head */
454	masse	1.8	temp->next= *stack_head;
455	masse	1.16	stack_head= new_head; / ...and voila! */
456	teddy	1.5	}
457	masse	1.11
458	masse	1.14	/* Compares two elements by reference. */
459	masse	1.11	extern void eq(stackitem** stack_head)
460			{
461			void left, right;
462			int result;
463
464	masse	1.17	if((stack_head)==NULL \|\| (stack_head)->next==NULL) {
465			printerr("Not enough elements to compare");
466	masse	1.11	return;
467	masse	1.17	}
468	masse	1.11
469			left= (*stack_head)->content.ptr;
470	masse	1.12	swap(stack_head);
471			right= (*stack_head)->content.ptr;
472	masse	1.11	result= (left==right);
473
474			toss(stack_head); toss(stack_head);
475			push_val(stack_head, (left==right));
476			}
477
478	masse	1.14	/* Negates the top element on the stack. */
479	masse	1.11	extern void not(stackitem** stack_head)
480			{
481			int value;
482
483	masse	1.17	if((stack_head)==NULL \|\| (stack_head)->type!=value) {
484			printerr("Stack empty or element is not a value");
485	masse	1.11	return;
486	masse	1.17	}
487	masse	1.11
488			value= (*stack_head)->content.val;
489			toss(stack_head);
490			push_val(stack_head, !value);
491			}
492
493	masse	1.14	/* Compares the two top elements on the stack and return 0 if they're the
494			same. */
495	masse	1.11	extern void neq(stackitem** stack_head)
496			{
497			eq(stack_head);
498			not(stack_head);
499			}
500	masse	1.12
501	masse	1.14	/* Give a symbol some content. */
502	masse	1.12	extern void def(stackitem** stack_head)
503			{
504			stackitem temp, value;
505
506			if(stack_head==NULL \|\| (stack_head)->next==NULL
507	masse	1.17	\|\| (*stack_head)->type!=ref) {
508			printerr("Define what?");
509	masse	1.12	return;
510	masse	1.17	}
511	masse	1.12
512			temp= (*stack_head)->content.ptr;
513			value= (*stack_head)->next;
514			temp->content= value->content;
515			value->content.ptr=NULL;
516			temp->type= value->type;
517
518			toss(stack_head); toss(stack_head);
519			}
520	masse	1.10
521	masse	1.14	/* Quit stack. */
522	teddy	1.5	extern void quit()
523			{
524			exit(EXIT_SUCCESS);
525	masse	1.24	}
526
527			/* Clear stack */
528			extern void clear(stackitem** stack_head)
529			{
530			while(*stack_head!=NULL)
531			toss(stack_head);
532	masse	1.1	}
533
534			int main()
535			{
536			stackitem* s= NULL;
537			hashtbl myhash;
538			char in_string[100];
539
540			init_hashtbl(myhash);
541
542			printf("okidok\n ");
543
544			while(fgets(in_string, 100, stdin) != NULL) {
545			stack_read(&s, myhash, in_string);
546			printf("okidok\n ");
547			}
548
549	masse	1.10	exit(EXIT_SUCCESS);
550	masse	1.1	}
551	teddy	1.3
552			/* Local Variables: */
553			/* compile-command:"make CFLAGS=\"-Wall -g -rdynamic -ldl\" stack" */
554			/* End: */