--- stack/stack.c	2002/03/10 13:00:01	1.101
+++ stack/stack.c	2002/03/10 20:08:47	1.102
@@ -70,15 +70,15 @@
 /* Discard the top element of the stack. */
 extern void toss(environment *env)
 {
-  stackitem *temp= env->head;
+  cons *temp= env->head;
 
-  if((env->head)==NULL) {
+  if(env->head==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
   
-  env->head= env->head->next;	/* Remove the top stack item */
+  env->head= env->head->cdr->content.c;	/* Remove the top stack item */
   free(temp);			/* Free the old top stack item */
 }
 
@@ -121,6 +121,7 @@
 
   nitem->item= nval;
   nitem->next= env->gc_ref;
+
   env->gc_ref= nitem;
 
   env->gc_count += sizeof(value);
@@ -134,20 +135,14 @@
    Marked values are not collected by the GC. */
 inline void gc_mark(value *val)
 {
-  stackitem *iterator;
-
-  if(val->gc.flag.mark)
+  if(val==NULL || val->gc.flag.mark)
     return;
 
   val->gc.flag.mark= 1;
 
-  if(val->type==list) {
-    iterator= val->content.ptr;
-
-    while(iterator!=NULL) {
-      gc_mark(iterator->item);
-      iterator= iterator->next;
-    }
+  if(val->type==tcons && val->content.c!=NULL) {
+    gc_mark(val->content.c->car);
+    gc_mark(val->content.c->cdr);
   }
 }
 
@@ -162,38 +157,34 @@
 /* Start GC */
 extern void gc_init(environment *env)
 {
-  stackitem *new_head= NULL, *titem, *iterator;
+  stackitem *new_head= NULL, *titem;
+  cons *iterator;
   symbol *tsymb;
   int i;
 
-  if(env->interactive){
+  if(env->interactive)
     printf("Garbage collecting.");
-  }
 
   /* Mark values on stack */
-  iterator= env->head;
-  while(iterator!=NULL) {
-    gc_mark(iterator->item);
-    iterator= iterator->next;
+  if(env->head!=NULL) {
+    gc_mark(env->head->car);
+    gc_mark(env->head->cdr);
   }
 
-  if(env->interactive){
+  if(env->interactive)
     printf(".");
-  }
+
 
   /* Mark values in hashtable */
-  for(i= 0; i<HASHTBLSIZE; i++) {
-    tsymb= env->symbols[i];
-    while(tsymb!=NULL) {
+  for(i= 0; i<HASHTBLSIZE; i++)
+    for(tsymb= env->symbols[i]; tsymb!=NULL; tsymb= tsymb->next)
       if (tsymb->val != NULL)
 	gc_mark(tsymb->val);
-      tsymb= tsymb->next;
-    }
-  }
 
-  if(env->interactive){
+
+  if(env->interactive)
     printf(".");
-  }
+
 
   env->gc_count= 0;
 
@@ -201,30 +192,21 @@
 
     if(!(env->gc_ref->item->gc.no_gc)){ /* neither mark nor protect */
 
-      switch(env->gc_ref->item->type) {	/* Remove content */
-      case string:
+      if(env->gc_ref->item->type==string) /* Remove content */
 	free(env->gc_ref->item->content.ptr);
-	break;
-      case list:
-	while(env->gc_ref->item->content.ptr!=NULL) {
-	  titem= env->gc_ref->item->content.ptr;
-	  env->gc_ref->item->content.ptr= titem->next;
-	  free(titem);
-	}
-      default:
-      }
+
       free(env->gc_ref->item);	/* Remove from gc_ref */
       titem= env->gc_ref->next;
       free(env->gc_ref);	/* Remove value */
       env->gc_ref= titem;
       continue;
-    } else {
-      env->gc_count += sizeof(value);
-      if(env->gc_ref->item->type == string)
-	env->gc_count += strlen(env->gc_ref->item->content.ptr);
-    }
+    } 
+
+    /* Keep values */     
+    env->gc_count += sizeof(value);
+    if(env->gc_ref->item->type==string)
+      env->gc_count += strlen(env->gc_ref->item->content.ptr);
     
-    /* Keep values */
     titem= env->gc_ref->next;
     env->gc_ref->next= new_head;
     new_head= env->gc_ref;
@@ -237,58 +219,48 @@
 
   env->gc_ref= new_head;
 
-  if(env->interactive){
+  if(env->interactive)
     printf("done\n");
-  }
 
 }
 
 /* Protect values from GC */
 void protect(value *val)
 {
-  stackitem *iterator;
-
-  if(val->gc.flag.protect)
+  if(val==NULL || 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;
-    }
+  if(val->type==tcons && val->content.c!=NULL) {
+    protect(val->content.c->car);
+    protect(val->content.c->cdr);
   }
 }
 
 /* Unprotect values from GC */
 void unprotect(value *val)
 {
-  stackitem *iterator;
-
-  if(!(val->gc.flag.protect))
+  if(val==NULL || !(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;
-    }
+  if(val->type==tcons && val->content.c!=NULL) {
+    unprotect(val->content.c->car);
+    unprotect(val->content.c->cdr);
   }
 }
 
 /* Push a value onto the stack */
 void push_val(environment *env, value *val)
 {
-  stackitem *new_item= malloc(sizeof(stackitem));
-  new_item->item= val;
-  new_item->next= env->head;
+  cons *new_item= malloc(sizeof(cons));
+  new_item->car= val;
+
+  new_item->cdr= new_val(env);
+  new_item->cdr->type= tcons;
+  new_item->cdr->content.c= env->head;
   env->head= new_item;
 }
 
@@ -358,13 +330,13 @@
     return;
   }
 
-  if(env->head->item->type!=string) {
+  if(env->head->car->type!=string) {
     printerr("Bad Argument Type");
     env->err= 2;
     return;
   }
 
-  new_string= mangle_str((const char *)(env->head->item->content.ptr));
+  new_string= mangle_str((const char *)(env->head->car->content.ptr));
 
   toss(env);
   if(env->err) return;
@@ -455,7 +427,7 @@
     env->err=1;
     return;
   }
-  typenum=env->head->item->type;
+  typenum=env->head->car->type;
   toss(env);
   switch(typenum){
   case integer:
@@ -473,42 +445,42 @@
   case func:
     push_sym(env, "function");
     break;
-  case list:
+  case tcons:
     push_sym(env, "list");
     break;
   }
 }    
 
 /* Prints the top element of the stack. */
-void print_h(stackitem *stack_head, int noquote)
+void print_h(cons *stack_head, int noquote)
 {
-  switch(stack_head->item->type) {
+  switch(stack_head->car->type) {
   case integer:
-    printf("%d", stack_head->item->content.i);
+    printf("%d", stack_head->car->content.i);
     break;
   case tfloat:
-    printf("%f", stack_head->item->content.f);
+    printf("%f", stack_head->car->content.f);
     break;
   case string:
     if(noquote)
-      printf("%s", (char*)stack_head->item->content.ptr);
+      printf("%s", (char*)stack_head->car->content.ptr);
     else
-      printf("\"%s\"", (char*)stack_head->item->content.ptr);
+      printf("\"%s\"", (char*)stack_head->car->content.ptr);
     break;
   case symb:
-    printf("%s", ((symbol *)(stack_head->item->content.ptr))->id);
+    printf("%s", ((symbol *)(stack_head->car->content.ptr))->id);
     break;
   case func:
-    printf("#<function %p>", (funcp)(stack_head->item->content.ptr));
+    printf("#<function %p>", (funcp)(stack_head->car->content.ptr));
     break;
-  case list:
+  case tcons:
     /* A list is just a stack, so make stack_head point to it */
-    stack_head=(stackitem *)(stack_head->item->content.ptr);
+    stack_head=(cons*)(stack_head->car->content.ptr);
     printf("[ ");
     while(stack_head != NULL) {
       print_h(stack_head, noquote);
       printf(" ");
-      stack_head=stack_head->next;
+      stack_head= stack_head->cdr->content.c;
     }
     printf("]");
     break;
@@ -553,10 +525,10 @@
 }
 
 /* Only to be called by function printstack. */
-void print_st(stackitem *stack_head, long counter)
+void print_st(cons *stack_head, long counter)
 { 
-  if(stack_head->next != NULL)
-    print_st(stack_head->next, counter+1);
+  if(stack_head->cdr->content.c != NULL)
+    print_st(stack_head->cdr->content.c, counter+1);
   printf("%ld: ", counter);
   print_h(stack_head, 0);
   nl();
@@ -576,34 +548,34 @@
 /* Swap the two top elements on the stack. */
 extern void swap(environment *env)
 {
-  stackitem *temp= env->head;
+  cons *temp= env->head;
   
-  if(env->head==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err=1;
     return;
   }
 
-  env->head= env->head->next;
-  temp->next= env->head->next;
-  env->head->next= temp;
+  env->head= env->head->cdr->content.c;
+  temp->cdr->content.c= env->head->cdr->content.c;
+  env->head->cdr->content.c= temp;
 } 
 
 /* Rotate the first three elements on the stack. */
 extern void rot(environment *env)
 {
-  stackitem *temp= env->head;
+  cons *temp= env->head;
   
-  if(env->head==NULL || env->head->next==NULL
-      || env->head->next->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL
+      || env->head->cdr->content.c->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err=1;
     return;
   }
 
-  env->head= env->head->next->next;
-  temp->next->next= env->head->next;
-  env->head->next= temp;
+  env->head= env->head->cdr->content.c->cdr->content.c;
+  temp->cdr->content.c->cdr->content.c= env->head->cdr->content.c;
+  env->head->cdr->content.c= temp;
 }
 
 /* Recall a value from a symbol, if bound */
@@ -611,22 +583,22 @@
 {
   value *val;
 
-  if(env->head == NULL) {
+  if(env->head==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
-  if(env->head->item->type!=symb) {
+  if(env->head->car->type!=symb) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
-  val=((symbol *)(env->head->item->content.ptr))->val;
+  val= ((symbol *)(env->head->car->content.ptr))->val;
   if(val == NULL){
     printerr("Unbound Variable");
-    env->err=3;
+    env->err= 3;
     return;
   }
   protect(val);
@@ -643,7 +615,7 @@
 {
   funcp in_func;
   value* temp_val;
-  stackitem* iterator;
+  cons* iterator;
 
  eval_start:
 
@@ -651,50 +623,50 @@
 
   if(env->head==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
-  switch(env->head->item->type) {
+  switch(env->head->car->type) {
     /* if it's a symbol */
   case symb:
     rcl(env);			/* get its contents */
     if(env->err) return;
-    if(env->head->item->type!=symb){ /* don't recurse symbols */
+    if(env->head->car->type!=symb){ /* don't recurse symbols */
       goto eval_start;
     }
     return;
 
     /* If it's a lone function value, run it */
   case func:
-    in_func= (funcp)(env->head->item->content.ptr);
+    in_func= (funcp)(env->head->car->content.ptr);
     toss(env); 
     if(env->err) return;
     return in_func(env);
 
     /* If it's a list */
-  case list:
-    temp_val= env->head->item;
+  case tcons:
+    temp_val= env->head->car;
     protect(temp_val);
 
     toss(env); if(env->err) return;
-    iterator= (stackitem*)temp_val->content.ptr;
+    iterator= (cons*)temp_val->content.ptr;
     
     while(iterator!=NULL) {
-      push_val(env, iterator->item);
+      push_val(env, iterator->car);
       
-      if(env->head->item->type==symb
-	 && (((symbol*)(env->head->item->content.ptr))->id[0] == ';')) {
+      if(env->head->car->type==symb
+	 && (((symbol*)(env->head->car->content.ptr))->id[0] == ';')) {
 	toss(env);
 	if(env->err) return;
 	
-	if(iterator->next == NULL){
+	if(iterator->cdr->content.c==NULL){
 	  goto eval_start;
 	}
 	eval(env);
 	if(env->err) return;
       }
-      iterator= iterator->next;
+      iterator= iterator->cdr->content.c;
     }
     unprotect(temp_val);
     return;
@@ -707,7 +679,7 @@
 /* Reverse (flip) a list */
 extern void rev(environment *env)
 {
-  stackitem *old_head, *new_head, *item;
+  cons *old_head, *new_head, *item;
 
   if((env->head)==NULL) {
     printerr("Too Few Arguments");
@@ -715,27 +687,27 @@
     return;
   }
 
-  if(env->head->item->type!=list) {
+  if(env->head->car->type!=tcons) {
     printerr("Bad Argument Type");
     env->err= 2;
     return;
   }
 
-  old_head= (stackitem *)(env->head->item->content.ptr);
+  old_head= (cons*)(env->head->car->content.ptr);
   new_head= NULL;
-  while(old_head != NULL){
+  while(old_head!=NULL) {
     item= old_head;
-    old_head= old_head->next;
-    item->next= new_head;
+    old_head= old_head->cdr->content.c;
+    item->cdr->content.c= new_head;
     new_head= item;
   }
-  env->head->item->content.ptr= new_head;
+  env->head->car->content.ptr= new_head;
 }
 
 /* Make a list. */
 extern void pack(environment *env)
 {
-  stackitem *iterator, *temp;
+  cons *iterator, *temp;
   value *pack;
 
   iterator= env->head;
@@ -743,23 +715,24 @@
   protect(pack);
 
   if(iterator==NULL
-     || (iterator->item->type==symb
-     && ((symbol*)(iterator->item->content.ptr))->id[0]=='[')) {
+     || (iterator->car->type==symb
+     && ((symbol*)(iterator->car->content.ptr))->id[0]=='[')) {
     temp= NULL;
     toss(env);
   } else {
     /* Search for first delimiter */
-    while(iterator->next!=NULL
-	  && (iterator->next->item->type!=symb
-	  || ((symbol*)(iterator->next->item->content.ptr))->id[0]!='['))
-      iterator= iterator->next;
+    while(iterator->cdr->content.c!=NULL
+	  && (iterator->cdr->content.c->car->type!=symb
+	  || ((symbol*)(iterator->cdr->content.c->car->content.ptr))->id[0]
+	      !='['))
+      iterator= iterator->cdr->content.c;
     
     /* Extract list */
     temp= env->head;
-    env->head= iterator->next;
-    iterator->next= NULL;
+    env->head= iterator->cdr->content.c;
+    iterator->cdr->content.c= NULL;
 
-    pack->type= list;
+    pack->type= tcons;
     pack->content.ptr= temp;
     
     if(env->head!=NULL)
@@ -777,7 +750,7 @@
 /* Relocate elements of the list on the stack. */
 extern void expand(environment *env)
 {
-  stackitem *temp, *new_head;
+  cons *temp, *new_head;
 
   /* Is top element a list? */
   if(env->head==NULL) {
@@ -785,7 +758,7 @@
     env->err= 1;
     return;
   }
-  if(env->head->item->type!=list) {
+  if(env->head->car->type!=tcons) {
     printerr("Bad Argument Type");
     env->err= 2;
     return;
@@ -797,16 +770,16 @@
     return;
 
   /* The first list element is the new stack head */
-  new_head= temp= env->head->item->content.ptr;
+  new_head= temp= env->head->car->content.ptr;
 
   toss(env);
 
   /* Find the end of the list */
-  while(temp->next!=NULL)
-    temp= temp->next;
+  while(temp->cdr->content.c!=NULL)
+    temp= temp->cdr->content.c;
 
   /* Connect the tail of the list with the old stack head */
-  temp->next= env->head;
+  temp->cdr->content.c= env->head;
   env->head= new_head;		/* ...and voila! */
 
 }
@@ -815,21 +788,19 @@
 extern void eq(environment *env)
 {
   void *left, *right;
-  int result;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
 
-  left= env->head->item->content.ptr;
+  left= env->head->car->content.ptr;
   swap(env);
-  right= env->head->item->content.ptr;
-  result= (left==right);
-  
+  right= env->head->car->content.ptr;
   toss(env); toss(env);
-  push_int(env, result);
+
+  push_int(env, left==right);
 }
 
 /* Negates the top element on the stack. */
@@ -837,19 +808,19 @@
 {
   int val;
 
-  if((env->head)==NULL) {
+  if(env->head==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
 
-  if(env->head->item->type!=integer) {
+  if(env->head->car->type!=integer) {
     printerr("Bad Argument Type");
     env->err= 2;
     return;
   }
 
-  val= env->head->item->content.i;
+  val= env->head->car->content.i;
   toss(env);
   push_int(env, !val);
 }
@@ -868,23 +839,23 @@
   symbol *sym;
 
   /* Needs two values on the stack, the top one must be a symbol */
-  if(env->head==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
 
-  if(env->head->item->type!=symb) {
+  if(env->head->car->type!=symb) {
     printerr("Bad Argument Type");
     env->err= 2;
     return;
   }
 
   /* long names are a pain */
-  sym= env->head->item->content.ptr;
+  sym= env->head->car->content.ptr;
 
   /* Bind the symbol to the value */
-  sym->val= env->head->next->item;
+  sym->val= env->head->cdr->content.c->car;
 
   toss(env); toss(env);
 } 
@@ -953,21 +924,21 @@
 extern void forget(environment *env)
 {
   char* sym_id;
-  stackitem *stack_head= env->head;
+  cons *stack_head= env->head;
 
   if(stack_head==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
   
-  if(stack_head->item->type!=symb) {
+  if(stack_head->car->type!=symb) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
-  sym_id= ((symbol*)(stack_head->item->content.ptr))->id;
+  sym_id= ((symbol*)(stack_head->car->content.ptr))->id;
   toss(env);
 
   return forget_sym(hash(env->symbols, sym_id));
@@ -1016,7 +987,7 @@
   }
 
   if(myenv.interactive) {
-    printf("Stack version $Revision: 1.101 $\n\
+    printf("Stack version $Revision: 1.102 $\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\
@@ -1039,8 +1010,8 @@
     if (myenv.err==4) {
       return EXIT_SUCCESS;	/* EOF */
     } else if(myenv.head!=NULL
-	      && myenv.head->item->type==symb
-	      && ((symbol*)(myenv.head->item->content.ptr))->id[0]==';') {
+	      && myenv.head->car->type==symb
+	      && ((symbol*)(myenv.head->car->content.ptr))->id[0]==';') {
       toss(&myenv); 		/* No error check in main */
       eval(&myenv);
     }
@@ -1059,16 +1030,16 @@
   char* new_string;
   value *a_val, *b_val;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
 
-  if(env->head->item->type==string
-     && env->head->next->item->type==string) {
-    a_val= env->head->item;
-    b_val= env->head->next->item;
+  if(env->head->car->type==string
+     && env->head->cdr->content.c->car->type==string) {
+    a_val= env->head->car;
+    b_val= env->head->cdr->content.c->car;
     protect(a_val); protect(b_val);
     toss(env); if(env->err) return;
     toss(env); if(env->err) return;
@@ -1083,44 +1054,44 @@
     return;
   }
   
-  if(env->head->item->type==integer
-     && env->head->next->item->type==integer) {
-    a=env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==integer) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    b=env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_int(env, b+a);
 
     return;
   }
 
-  if(env->head->item->type==tfloat
-     && env->head->next->item->type==tfloat) {
-    fa= env->head->item->content.f;
+  if(env->head->car->type==tfloat
+     && env->head->cdr->content.c->car->type==tfloat) {
+    fa= env->head->car->content.f;
     toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
+    fb= env->head->car->content.f;
     toss(env); if(env->err) return;
     push_float(env, fb+fa);
     
     return;
   }
 
-  if(env->head->item->type==tfloat
-     && env->head->next->item->type==integer) {
-    fa= env->head->item->content.f;
+  if(env->head->car->type==tfloat
+     && env->head->cdr->content.c->car->type==integer) {
+    fa= env->head->car->content.f;
     toss(env); if(env->err) return;
-    b= env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_float(env, b+fa);
     
     return;
   }
 
-  if(env->head->item->type==integer
-     && env->head->next->item->type==tfloat) {
-    a= env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==tfloat) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
+    fb= env->head->car->content.f;
     toss(env); if(env->err) return;
     push_float(env, fb+a);
 
@@ -1137,50 +1108,50 @@
   int a, b;
   float fa, fb;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err=1;
     return;
   }
   
-  if(env->head->item->type==integer
-     && env->head->next->item->type==integer) {
-    a=env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==integer) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    b=env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_int(env, b-a);
 
     return;
   }
 
-  if(env->head->item->type==tfloat
-     && env->head->next->item->type==tfloat) {
-    fa= env->head->item->content.f;
+  if(env->head->car->type==tfloat
+     && env->head->cdr->content.c->car->type==tfloat) {
+    fa= env->head->car->content.f;
     toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
+    fb= env->head->car->content.f;
     toss(env); if(env->err) return;
     push_float(env, fb-fa);
     
     return;
   }
 
-  if(env->head->item->type==tfloat
-     && env->head->next->item->type==integer) {
-    fa= env->head->item->content.f;
+  if(env->head->car->type==tfloat
+     && env->head->cdr->content.c->car->type==integer) {
+    fa= env->head->car->content.f;
     toss(env); if(env->err) return;
-    b= env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_float(env, b-fa);
     
     return;
   }
 
-  if(env->head->item->type==integer
-     && env->head->next->item->type==tfloat) {
-    a= env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==tfloat) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
+    fb= env->head->car->content.f;
     toss(env); if(env->err) return;
     push_float(env, fb-a);
 
@@ -1197,50 +1168,50 @@
   int a, b;
   float fa, fb;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
   
-  if(env->head->item->type==integer
-     && env->head->next->item->type==integer) {
-    a=env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==integer) {
+    a=env->head->car->content.i;
     toss(env); if(env->err) return;
-    b=env->head->item->content.i;
+    b=env->head->car->content.i;
     toss(env); if(env->err) return;
     push_int(env, b>a);
 
     return;
   }
 
-  if(env->head->item->type==tfloat
-     && env->head->next->item->type==tfloat) {
-    fa= env->head->item->content.f;
+  if(env->head->car->type==tfloat
+     && env->head->cdr->content.c->car->type==tfloat) {
+    fa= env->head->car->content.f;
     toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
+    fb= env->head->car->content.f;
     toss(env); if(env->err) return;
     push_int(env, fb>fa);
     
     return;
   }
 
-  if(env->head->item->type==tfloat
-     && env->head->next->item->type==integer) {
-    fa= env->head->item->content.f;
+  if(env->head->car->type==tfloat
+     && env->head->cdr->content.c->car->type==integer) {
+    fa= env->head->car->content.f;
     toss(env); if(env->err) return;
-    b= env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_int(env, b>fa);
     
     return;
   }
 
-  if(env->head->item->type==integer
-     && env->head->next->item->type==tfloat) {
-    a= env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==tfloat) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
+    fb= env->head->car->content.f;
     toss(env); if(env->err) return;
     push_int(env, fb>a);
 
@@ -1275,7 +1246,7 @@
 /* Return copy of a value */
 value *copy_val(environment *env, value *old_value)
 {
-  stackitem *old_item, *new_item, *prev_item;
+  cons *old_item, *new_item, *prev_item;
   value *new_value;
 
   protect(old_value);
@@ -1294,22 +1265,24 @@
     (char *)(new_value->content.ptr)= 
       strdup((char *)(old_value->content.ptr));
     break;
-  case list:
+  case tcons:
     new_value->content.ptr= NULL;
 
     prev_item= NULL;
-    old_item= (stackitem*)(old_value->content.ptr);
+    old_item= (cons*)(old_value->content.ptr);
 
     while(old_item != NULL) {	/* While list is not empty */
-      new_item= malloc(sizeof(stackitem));
-      new_item->item= copy_val(env, old_item->item); /* recurse */
-      new_item->next= NULL;
+      new_item= malloc(sizeof(cons));
+      new_item->car= copy_val(env, old_item->car); /* recurse */
+      new_item->cdr= new_val(env);
+      new_item->cdr->type= tcons;
+      new_item->cdr->content.c= NULL;
       if(prev_item != NULL)	/* If this wasn't the first item */
-	prev_item->next= new_item; /* point the previous item to the
+	prev_item->cdr->content.c= new_item; /* point the previous item to the
                                      new item */
       else
 	new_value->content.ptr= new_item;
-      old_item= old_item->next;
+      old_item= old_item->cdr->content.c;
       prev_item= new_item;
     }	  
     break;
@@ -1323,12 +1296,12 @@
 /* "dup"; duplicates an item on the stack */
 extern void sx_647570(environment *env)
 {
-  if((env->head)==NULL) {
+  if(env->head==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
-  push_val(env, copy_val(env, env->head->item));
+  push_val(env, copy_val(env, env->head->car));
 }
 
 /* "if", If-Then */
@@ -1336,22 +1309,22 @@
 {
   int truth;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
 
-  if(env->head->next->item->type != integer) {
+  if(env->head->cdr->content.c->car->type != integer) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
   
   swap(env);
   if(env->err) return;
   
-  truth=env->head->item->content.i;
+  truth=env->head->car->content.i;
 
   toss(env);
   if(env->err) return;
@@ -1367,23 +1340,23 @@
 {
   int truth;
 
-  if((env->head)==NULL || env->head->next==NULL
-     || env->head->next->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL
+     || env->head->cdr->content.c->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
-  if(env->head->next->next->item->type != integer) {
+  if(env->head->cdr->content.c->cdr->content.c->car->type!=integer) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
   
   rot(env);
   if(env->err) return;
   
-  truth=env->head->item->content.i;
+  truth= env->head->car->content.i;
 
   toss(env);
   if(env->err) return;
@@ -1404,17 +1377,17 @@
   int truth;
   value *loop, *test;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
-  loop= env->head->item;
+  loop= env->head->car;
   protect(loop);
   toss(env); if(env->err) return;
 
-  test= env->head->item;
+  test= env->head->car;
   protect(test);
   toss(env); if(env->err) return;
 
@@ -1422,13 +1395,13 @@
     push_val(env, test);
     eval(env);
     
-    if(env->head->item->type != integer) {
+    if(env->head->car->type != integer) {
       printerr("Bad Argument Type");
       env->err= 2;
       return;
     }
     
-    truth= env->head->item->content.i;
+    truth= env->head->car->content.i;
     toss(env); if(env->err) return;
     
     if(truth) {
@@ -1450,28 +1423,28 @@
   value *loop;
   int foo1, foo2;
 
-  if(env->head==NULL || env->head->next==NULL 
-     || env->head->next->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL 
+     || env->head->cdr->content.c->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
 
-  if(env->head->next->item->type!=integer
-     || env->head->next->next->item->type!=integer) {
+  if(env->head->cdr->content.c->car->type!=integer
+     || env->head->cdr->content.c->cdr->content.c->car->type!=integer) {
     printerr("Bad Argument Type");
     env->err= 2;
     return;
   }
 
-  loop= env->head->item;
+  loop= env->head->car;
   protect(loop);
   toss(env); if(env->err) return;
 
-  foo2= env->head->item->content.i;
+  foo2= env->head->car->content.i;
   toss(env); if(env->err) return;
 
-  foo1= env->head->item->content.i;
+  foo1= env->head->car->content.i;
   toss(env); if(env->err) return;
 
   if(foo1<=foo2) {
@@ -1496,35 +1469,35 @@
 extern void foreach(environment *env)
 {  
   value *loop, *foo;
-  stackitem *iterator;
+  cons *iterator;
   
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
 
-  if(env->head->next->item->type != list) {
+  if(env->head->cdr->content.c->car->type!=tcons) {
     printerr("Bad Argument Type");
     env->err= 2;
     return;
   }
 
-  loop= env->head->item;
+  loop= env->head->car;
   protect(loop);
   toss(env); if(env->err) return;
 
-  foo= env->head->item;
+  foo= env->head->car;
   protect(foo);
   toss(env); if(env->err) return;
 
   iterator= foo->content.ptr;
 
   while(iterator!=NULL) {
-    push_val(env, iterator->item);
+    push_val(env, iterator->car);
     push_val(env, loop);
     eval(env); if(env->err) return;
-    iterator= iterator->next;
+    iterator= iterator->cdr->content.c;
   }
   unprotect(loop); unprotect(foo);
 }
@@ -1533,25 +1506,25 @@
 extern void to(environment *env)
 {
   int ending, start, i;
-  stackitem *iterator, *temp;
+  cons *iterator, *temp;
   value *pack;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
-  if(env->head->item->type!=integer 
-     || env->head->next->item->type!=integer) {
+  if(env->head->car->type!=integer 
+     || env->head->cdr->content.c->car->type!=integer) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
-  ending= env->head->item->content.i;
+  ending= env->head->car->content.i;
   toss(env); if(env->err) return;
-  start= env->head->item->content.i;
+  start= env->head->car->content.i;
   toss(env); if(env->err) return;
 
   push_sym(env, "[");
@@ -1569,23 +1542,24 @@
   protect(pack);
 
   if(iterator==NULL
-     || (iterator->item->type==symb
-     && ((symbol*)(iterator->item->content.ptr))->id[0]=='[')) {
+     || (iterator->car->type==symb
+     && ((symbol*)(iterator->car->content.ptr))->id[0]=='[')) {
     temp= NULL;
     toss(env);
   } else {
     /* Search for first delimiter */
-    while(iterator->next!=NULL
-	  && (iterator->next->item->type!=symb
-	  || ((symbol*)(iterator->next->item->content.ptr))->id[0]!='['))
-      iterator= iterator->next;
+    while(iterator->cdr->content.c!=NULL
+	  && (iterator->cdr->content.c->car->type!=symb
+	  || ((symbol*)(iterator->cdr->content.c->car->content.ptr))->id[0]
+	      !='['))
+      iterator= iterator->cdr->content.c;
     
     /* Extract list */
     temp= env->head;
-    env->head= iterator->next;
-    iterator->next= NULL;
+    env->head= iterator->cdr->content.c;
+    iterator->cdr->content.c= NULL;
 
-    pack->type= list;
+    pack->type= tcons;
     pack->content.ptr= temp;
     
     if(env->head!=NULL)
@@ -1635,14 +1609,14 @@
     }
     readline(env); if(env->err) return;
 
-    if(((char *)(env->head->item->content.ptr))[0]=='\0'){
+    if(((char *)(env->head->car->content.ptr))[0]=='\0'){
       env->err= 4;		/* "" means EOF */
       return;
     }
     
-    env->in_string= malloc(strlen(env->head->item->content.ptr)+1);
+    env->in_string= malloc(strlen(env->head->car->content.ptr)+1);
     env->free_string= env->in_string; /* Save the original pointer */
-    strcpy(env->in_string, env->head->item->content.ptr);
+    strcpy(env->in_string, env->head->car->content.ptr);
     toss(env); if(env->err) return;
   }
   
@@ -1695,39 +1669,39 @@
 {
   int freq, dur, period, ticks;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
-  if(env->head->item->type!=integer
-     || env->head->next->item->type!=integer) {
+  if(env->head->car->type!=integer
+     || env->head->cdr->content.c->car->type!=integer) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
-  dur=env->head->item->content.i;
+  dur= env->head->car->content.i;
   toss(env);
-  freq=env->head->item->content.i;
+  freq= env->head->car->content.i;
   toss(env);
 
-  period=1193180/freq;		/* convert freq from Hz to period
+  period= 1193180/freq;		/* convert freq from Hz to period
                                    length */
-  ticks=dur*.001193180;		/* convert duration from µseconds to
+  ticks= dur*.001193180;	/* convert duration from µseconds to
 				   timer ticks */
 
 /*    ticks=dur/1000; */
 
-  /*  if (ioctl(STDOUT_FILENO, KDMKTONE, (125<<16) + 0x637)==0) */
+      /*  if (ioctl(STDOUT_FILENO, KDMKTONE, (125<<16) + 0x637)==0) */
   switch (ioctl(STDOUT_FILENO, KDMKTONE, (ticks<<16) | period)){
   case 0:
     usleep(dur);
     return;
   case -1:
     perror("beep");
-    env->err=5;
+    env->err= 5;
     return;
   default:
     abort();
@@ -1739,19 +1713,19 @@
 {
   int dur;
 
-  if((env->head)==NULL) {
+  if(env->head==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
-  if(env->head->item->type!=integer) {
+  if(env->head->car->type!=integer) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
-  dur=env->head->item->content.i;
+  dur=env->head->car->content.i;
   toss(env);
 
   usleep(dur);
@@ -2048,50 +2022,50 @@
   int a, b;
   float fa, fb;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
   
-  if(env->head->item->type==integer
-     && env->head->next->item->type==integer) {
-    a=env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==integer) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    b=env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_int(env, b*a);
 
     return;
   }
 
-  if(env->head->item->type==tfloat
-     && env->head->next->item->type==tfloat) {
-    fa= env->head->item->content.f;
+  if(env->head->car->type==tfloat
+     && env->head->cdr->content.c->car->type==tfloat) {
+    fa= env->head->car->content.f;
     toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
+    fb= env->head->car->content.f;
     toss(env); if(env->err) return;
     push_float(env, fb*fa);
     
     return;
   }
 
-  if(env->head->item->type==tfloat
-     && env->head->next->item->type==integer) {
-    fa= env->head->item->content.f;
+  if(env->head->car->type==tfloat
+     && env->head->cdr->content.c->car->type==integer) {
+    fa= env->head->car->content.f;
     toss(env); if(env->err) return;
-    b= env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_float(env, b*fa);
     
     return;
   }
 
-  if(env->head->item->type==integer
-     && env->head->next->item->type==tfloat) {
-    a= env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==tfloat) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
+    fb= env->head->car->content.f;
     toss(env); if(env->err) return;
     push_float(env, fb*a);
 
@@ -2099,7 +2073,7 @@
   }
 
   printerr("Bad Argument Type");
-  env->err=2;
+  env->err= 2;
 }
 
 /* "/" */
@@ -2108,50 +2082,50 @@
   int a, b;
   float fa, fb;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
   
-  if(env->head->item->type==integer
-     && env->head->next->item->type==integer) {
-    a=env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==integer) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    b=env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_float(env, b/a);
 
     return;
   }
 
-  if(env->head->item->type==tfloat
-     && env->head->next->item->type==tfloat) {
-    fa= env->head->item->content.f;
+  if(env->head->car->type==tfloat
+     && env->head->cdr->content.c->car->type==tfloat) {
+    fa= env->head->car->content.f;
     toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
+    fb= env->head->car->content.f;
     toss(env); if(env->err) return;
     push_float(env, fb/fa);
     
     return;
   }
 
-  if(env->head->item->type==tfloat
-     && env->head->next->item->type==integer) {
-    fa= env->head->item->content.f;
+  if(env->head->car->type==tfloat
+     && env->head->cdr->content.c->car->type==integer) {
+    fa= env->head->car->content.f;
     toss(env); if(env->err) return;
-    b= env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_float(env, b/fa);
     
     return;
   }
 
-  if(env->head->item->type==integer
-     && env->head->next->item->type==tfloat) {
-    a= env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==tfloat) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
+    fb= env->head->car->content.f;
     toss(env); if(env->err) return;
     push_float(env, fb/a);
 
@@ -2159,7 +2133,7 @@
   }
 
   printerr("Bad Argument Type");
-  env->err=2;
+  env->err= 2;
 }
 
 /* "mod" */
@@ -2167,17 +2141,17 @@
 {
   int a, b;
 
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
   
-  if(env->head->item->type==integer
-     && env->head->next->item->type==integer) {
-    a= env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==integer) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    b= env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_int(env, b%a);
 
@@ -2185,7 +2159,7 @@
   }
 
   printerr("Bad Argument Type");
-  env->err=2;
+  env->err= 2;
 }
 
 /* "div" */
@@ -2193,17 +2167,17 @@
 {
   int a, b;
   
-  if((env->head)==NULL || env->head->next==NULL) {
+  if(env->head==NULL || env->head->cdr->content.c==NULL) {
     printerr("Too Few Arguments");
     env->err= 1;
     return;
   }
 
-  if(env->head->item->type==integer
-     && env->head->next->item->type==integer) {
-    a= env->head->item->content.i;
+  if(env->head->car->type==integer
+     && env->head->cdr->content.c->car->type==integer) {
+    a= env->head->car->content.i;
     toss(env); if(env->err) return;
-    b= env->head->item->content.i;
+    b= env->head->car->content.i;
     toss(env); if(env->err) return;
     push_int(env, (int)b/a);