--- stack/stack.c	2002/03/10 07:55:13	1.96
+++ stack/stack.c	2002/03/10 12:05:20	1.100
@@ -48,10 +48,9 @@
 {
   int i;
 
-  env->gc_limit= 200;
+  env->gc_limit= 400000;
   env->gc_count= 0;
   env->gc_ref= NULL;
-  env->gc_protect= NULL;
 
   env->head= NULL;
   for(i= 0; i<HASHTBLSIZE; i++)
@@ -81,8 +80,6 @@
   
   env->head= env->head->next;	/* Remove the top stack item */
   free(temp);			/* Free the old top stack item */
-
-  env->gc_limit--;
 }
 
 /* Returns a pointer to a pointer to an element in the hash table. */
@@ -126,7 +123,9 @@
   nitem->next= env->gc_ref;
   env->gc_ref= nitem;
 
-  env->gc_count++;
+  env->gc_count+=sizeof(value);
+  nval->gc.flag.mark= 0;
+  nval->gc.flag.protect= 0;
 
   return nval;
 }
@@ -137,10 +136,10 @@
 {
   stackitem *iterator;
 
-  if(val==NULL || val->gc_garb==0)
+  if(val->gc.flag.mark)
     return;
 
-  val->gc_garb= 0;
+  val->gc.flag.mark= 1;
 
   if(val->type==list) {
     iterator= val->content.ptr;
@@ -167,18 +166,8 @@
   symbol *tsymb;
   int i;
 
-  /* Garb by default */
-  iterator= env->gc_ref;
-  while(iterator!=NULL) {
-    iterator->item->gc_garb= 1;
-    iterator= iterator->next;
-  }
-
-  /* Mark protected values */
-  iterator= env->gc_protect;
-  while(iterator!=NULL) {
-    gc_mark(iterator->item);
-    iterator= iterator->next;
+  if(env->interactive){
+    printf("Garbage collecting.", env->gc_count, env->gc_limit);
   }
 
   /* Mark values on stack */
@@ -188,20 +177,29 @@
     iterator= iterator->next;
   }
 
+  if(env->interactive){
+    printf(".");
+  }
+
   /* Mark values in hashtable */
   for(i= 0; i<HASHTBLSIZE; i++) {
     tsymb= env->symbols[i];
     while(tsymb!=NULL) {
-      gc_mark(tsymb->val);
+      if (tsymb->val != NULL)
+	gc_mark(tsymb->val);
       tsymb= tsymb->next;
     }
   }
 
+  if(env->interactive){
+    printf(".");
+  }
+
   env->gc_count= 0;
 
   while(env->gc_ref!=NULL) {	/* Sweep unused values */
 
-    if(env->gc_ref->item->gc_garb) {
+    if(!(env->gc_ref->item->gc.no_gc)){ /* neither mark nor protect */
 
       switch(env->gc_ref->item->type) {	/* Remove content */
       case string:
@@ -213,42 +211,73 @@
 	  env->gc_ref->item->content.ptr= titem->next;
 	  free(titem);
 	}
-	break;
       default:
-	break;
       }
       free(env->gc_ref->item);	/* Remove from gc_ref */
       titem= env->gc_ref->next;
       free(env->gc_ref);	/* Remove value */
       env->gc_ref= titem;
-    } else {			/* Keep values */
-      titem= env->gc_ref->next;
-      env->gc_ref->next= new_head;
-      new_head= env->gc_ref;
-      env->gc_ref= titem;
-      env->gc_count++;
+      continue;
+    } else {
+      env->gc_count += sizeof(value);
     }
+    
+    /* Keep values */
+    titem= env->gc_ref->next;
+    env->gc_ref->next= new_head;
+    new_head= env->gc_ref;
+    new_head->item->gc.flag.mark= 0;
+    env->gc_ref= titem;
   }
 
-  env->gc_limit= env->gc_count*2;
+  if (env->gc_limit < env->gc_count*2)
+    env->gc_limit= env->gc_count*2;
   env->gc_ref= new_head;
+
+  if(env->interactive){
+    printf("done\n");
+  }
+
 }
 
 /* Protect values from GC */
-void protect(environment *env, value *val)
+void protect(value *val)
 {
-  stackitem *new_item= malloc(sizeof(stackitem));
-  new_item->item= val;
-  new_item->next= env->gc_protect;
-  env->gc_protect= new_item;
+  stackitem *iterator;
+
+  if(val->gc.flag.protect)
+    return;
+
+  val->gc.flag.protect= 1;
+
+  if(val->type==list) {
+    iterator= val->content.ptr;
+
+    while(iterator!=NULL) {
+      protect(iterator->item);
+      iterator= iterator->next;
+    }
+  }
 }
 
 /* Unprotect values from GC */
-void unprotect(environment *env)
+void unprotect(value *val)
 {
-  stackitem *temp= env->gc_protect;
-  env->gc_protect= env->gc_protect->next;
-  free(temp);
+  stackitem *iterator;
+
+  if(!(val->gc.flag.protect))
+    return;
+
+  val->gc.flag.protect= 0;
+
+  if(val->type==list) {
+    iterator= val->content.ptr;
+
+    while(iterator!=NULL) {
+      unprotect(iterator->item);
+      iterator= iterator->next;
+    }
+  }
 }
 
 /* Push a value onto the stack */
@@ -354,9 +383,9 @@
   char *mangled;		/* Mangled function name */
 
   new_value= new_val(env);
-  protect(env, new_value);
+  protect(new_value);
   new_fvalue= new_val(env);
-  protect(env, new_fvalue);
+  protect(new_fvalue);
 
   /* The new value is a symbol */
   new_value->type= symb;
@@ -402,7 +431,7 @@
   }
 
   push_val(env, new_value);
-  unprotect(env); unprotect(env);
+  unprotect(new_value); unprotect(new_fvalue);
 }
 
 /* Print newline. */
@@ -595,11 +624,11 @@
     env->err=3;
     return;
   }
-  protect(env, val);
+  protect(val);
   toss(env);		/* toss the symbol */
   if(env->err) return;
   push_val(env, val); /* Return its bound value */
-  unprotect(env);
+  unprotect(val);
 }
 
 /* If the top element is a symbol, determine if it's bound to a
@@ -641,7 +670,7 @@
     /* If it's a list */
   case list:
     temp_val= env->head->item;
-    protect(env, temp_val);
+    protect(temp_val);
 
     toss(env); if(env->err) return;
     iterator= (stackitem*)temp_val->content.ptr;
@@ -650,7 +679,7 @@
       push_val(env, iterator->item);
       
       if(env->head->item->type==symb
-	&& strcmp(";", ((symbol*)(env->head->item->content.ptr))->id)==0) {
+	 && (((symbol*)(env->head->item->content.ptr))->id[0] == ';')) {
 	toss(env);
 	if(env->err) return;
 	
@@ -662,7 +691,7 @@
       }
       iterator= iterator->next;
     }
-    unprotect(env);
+    unprotect(temp_val);
     return;
 
   default:
@@ -706,7 +735,7 @@
 
   iterator= env->head;
   pack= new_val(env);
-  protect(env, pack);
+  protect(pack);
 
   if(iterator==NULL
      || (iterator->item->type==symb
@@ -737,7 +766,7 @@
   push_val(env, pack);
   rev(env);
 
-  unprotect(env);
+  unprotect(pack);
 }
 
 /* Relocate elements of the list on the stack. */
@@ -982,7 +1011,7 @@
   }
 
   if(myenv.interactive) {
-    printf("Stack version $Revision: 1.96 $\n\
+    printf("Stack version $Revision: 1.100 $\n\
 Copyright (C) 2002  Mats Alritzson and Teddy Hogeborn\n\
 Stack comes with ABSOLUTELY NO WARRANTY; for details type `warranty;'.\n\
 This is free software, and you are welcome to redistribute it\n\
@@ -1035,7 +1064,7 @@
      && env->head->next->item->type==string) {
     a_val= env->head->item;
     b_val= env->head->next->item;
-    protect(env, a_val); protect(env, b_val);
+    protect(a_val); protect(b_val);
     toss(env); if(env->err) return;
     toss(env); if(env->err) return;
     len= strlen(a_val->content.ptr)+strlen(b_val->content.ptr)+1;
@@ -1043,7 +1072,7 @@
     strcpy(new_string, b_val->content.ptr);
     strcat(new_string, a_val->content.ptr);
     push_cstring(env, new_string);
-    unprotect(env); unprotect(env);
+    unprotect(a_val); unprotect(b_val);
     free(new_string);
     
     return;
@@ -1244,9 +1273,9 @@
   stackitem *old_item, *new_item, *prev_item;
   value *new_value;
 
-  protect(env, old_value);
+  protect(old_value);
   new_value= new_val(env);
-  protect(env, new_value);
+  protect(new_value);
   new_value->type= old_value->type;
 
   switch(old_value->type){
@@ -1281,7 +1310,7 @@
     break;
   }
 
-  unprotect(env); unprotect(env);
+  unprotect(old_value); unprotect(new_value);
 
   return new_value;
 }
@@ -1377,11 +1406,11 @@
   }
 
   loop= env->head->item;
-  protect(env, loop);
+  protect(loop);
   toss(env); if(env->err) return;
 
   test= env->head->item;
-  protect(env, test);
+  protect(test);
   toss(env); if(env->err) return;
 
   do {
@@ -1406,7 +1435,7 @@
   
   } while(truth);
 
-  unprotect(env); unprotect(env);
+  unprotect(loop); unprotect(test);
 }
 
 
@@ -1431,7 +1460,7 @@
   }
 
   loop= env->head->item;
-  protect(env, loop);
+  protect(loop);
   toss(env); if(env->err) return;
 
   foo2= env->head->item->content.i;
@@ -1455,7 +1484,7 @@
       foo1--;
     }
   }
-  unprotect(env);
+  unprotect(loop);
 }
 
 /* Variant of for-loop */
@@ -1477,11 +1506,11 @@
   }
 
   loop= env->head->item;
-  protect(env, loop);
+  protect(loop);
   toss(env); if(env->err) return;
 
   foo= env->head->item;
-  protect(env, foo);
+  protect(foo);
   toss(env); if(env->err) return;
 
   iterator= foo->content.ptr;
@@ -1492,7 +1521,7 @@
     eval(env); if(env->err) return;
     iterator= iterator->next;
   }
-  unprotect(env); unprotect(env);
+  unprotect(loop); unprotect(foo);
 }
 
 /* "to" */
@@ -1532,7 +1561,7 @@
 
   iterator= env->head;
   pack= new_val(env);
-  protect(env, pack);
+  protect(pack);
 
   if(iterator==NULL
      || (iterator->item->type==symb
@@ -1562,7 +1591,7 @@
 
   push_val(env, pack);
 
-  unprotect(env);
+  unprotect(pack);
 }
 
 /* Read a string */