--- stack/stack.c	2002/02/13 00:16:00	1.75
+++ stack/stack.c	2002/02/16 00:51:32	1.88
@@ -1,4 +1,4 @@
-/* printf, sscanf, fgets, fprintf */
+/* printf, sscanf, fgets, fprintf, fopen, perror */
 #include <stdio.h>
 /* exit, EXIT_SUCCESS, malloc, free */
 #include <stdlib.h>
@@ -8,108 +8,37 @@
 #include <dlfcn.h>
 /* strcmp, strcpy, strlen, strcat, strdup */
 #include <string.h>
+/* getopt, STDIN_FILENO, STDOUT_FILENO */
+#include <unistd.h>
+/* EX_NOINPUT, EX_USAGE */
+#include <sysexits.h>
+/* mtrace, muntrace */
+#include <mcheck.h>
 
-#define HASHTBLSIZE 2048
-
-/* First, define some types. */
-
-/* A value of some type */
-typedef struct {
-  enum {
-    integer,
-    string,
-    func,			/* Function pointer */
-    symb, 
-    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 */
-
-  int refcount;			/* Reference counter */
-
-} value;
-
-/* A symbol with a name and possible value */
-/* (These do not need reference counters, they are kept unique by
-   hashing.) */
-typedef struct symbol_struct {
-  char *id;			/* Symbol name */
-  value *val;			/* The value (if any) bound to it */
-  struct symbol_struct *next;	/* In case of hashing conflicts, a */
-} symbol;			/* symbol is a kind of stack item. */
-
-/* A type for a hash table for symbols */
-typedef symbol *hashtbl[HASHTBLSIZE]; /* Hash table declaration */
-
-/* An item (value) on a stack */
-typedef struct stackitem_struct
-{
-  value *item;			/* The value on the stack */
-				/* (This is never NULL) */
-  struct stackitem_struct *next; /* Next item */
-} stackitem;
-
-/* An environment; gives access to the stack and a hash table of
-   defined symbols */
-typedef struct {
-  stackitem *head;		/* Head of the stack */
-  hashtbl symbols;		/* Hash table of all variable bindings */
-  int err;			/* Error flag */
-  int non_eval_flag;
-  char *in_string;		/* Input pending to be read */
-} environment;
-
-/* A type for pointers to external functions */
-typedef void (*funcp)(environment *); /* funcp is a pointer to a void
-					 function (environment *) */
+#include "stack.h"
 
 /* Initialize a newly created environment */
 void init_env(environment *env)
 {
   int i;
 
-  env->in_string= NULL;
-  env->err= 0;
-  env->non_eval_flag= 0;
+  env->gc_limit= 20;
+  env->gc_count= 0;
+
+  env->head= NULL;
   for(i= 0; i<HASHTBLSIZE; i++)
     env->symbols[i]= NULL;
+  env->err= 0;
+  env->in_string= NULL;
+  env->free_string= NULL;
+  env->inputstream= stdin;
+  env->interactive= 1;
 }
 
 void printerr(const char* in_string) {
   fprintf(stderr, "Err: %s\n", in_string);
 }
 
-/* Throw away a value */
-void free_val(value *val){
-  stackitem *item, *temp;
-
-  val->refcount--;		/* Decrease the reference count */
-  if(val->refcount == 0){
-    switch (val->type){		/* and free the contents if necessary */
-    case string:
-      free(val->content.ptr);
-      break;
-    case list:			/* lists needs to be freed recursively */
-      item=val->content.ptr;
-      while(item != NULL) {	/* for all stack items */
-	free_val(item->item);	/* free the value */
-	temp=item->next;	/* save next ptr */
-	free(item);		/* free the stackitem */
-	item=temp;		/* go to next stackitem */
-      }
-      free(val);		/* Free the actual list value */
-      break;
-    case integer:
-    case func:
-    case symb:
-      break;
-    }
-  }
-}
-
 /* Discard the top element of the stack. */
 extern void toss(environment *env)
 {
@@ -121,7 +50,6 @@
     return;
   }
   
-  free_val(env->head->item);	/* Free the value */
   env->head= env->head->next;	/* Remove the top stack item */
   free(temp);			/* Free the old top stack item */
 }
@@ -155,12 +83,110 @@
   }
 }
 
+value* new_val(environment *env) {
+  value *nval= malloc(sizeof(value));
+  stackitem *nitem= malloc(sizeof(stackitem));
+
+  if(env->gc_count >= env->gc_limit)
+    gc_init(env);
+
+  nval->content.ptr= NULL;
+
+  nitem->item= nval;
+  nitem->next= env->gc_ref;
+  env->gc_ref= nitem;
+
+  env->gc_count++;
+
+  return nval;
+}
+
+void gc_mark(value *val) {
+  stackitem *iterator;
+
+  if(val==NULL || val->gc_garb==0)
+    return;
+
+  val->gc_garb= 0;
+
+  if(val->type==list) {
+    iterator= val->content.ptr;
+
+    while(iterator!=NULL) {
+      gc_mark(iterator->item);
+      iterator= iterator->next;
+    }
+  }
+}
+
+extern void gc_init(environment *env) {
+  stackitem *new_head= NULL, *titem, *iterator= env->gc_ref;
+  symbol *tsymb;
+  int i;
+
+  while(iterator!=NULL) {
+    iterator->item->gc_garb= 1;
+    iterator= iterator->next;
+  }
+
+  /* Mark */
+  iterator= env->head;
+  while(iterator!=NULL) {
+    gc_mark(iterator->item);
+    iterator= iterator->next;
+  }
+
+  for(i= 0; i<HASHTBLSIZE; i++) {
+    tsymb= env->symbols[i];
+    while(tsymb!=NULL) {
+      gc_mark(tsymb->val);
+      tsymb= tsymb->next;
+    }
+  }
+
+  env->gc_count= 0;
+
+  /* Sweep */
+  while(env->gc_ref!=NULL) {
+    if(env->gc_ref->item->gc_garb) {
+      switch(env->gc_ref->item->type) {
+      case string:
+	free(env->gc_ref->item->content.ptr);
+	break;
+      case integer:
+	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);
+	}
+	break;
+      default:
+	break;
+      }
+      free(env->gc_ref->item);
+      titem= env->gc_ref->next;
+      free(env->gc_ref);
+      env->gc_ref= titem;
+    } else {
+      titem= env->gc_ref->next;
+      env->gc_ref->next= new_head;
+      new_head= env->gc_ref;
+      env->gc_ref= titem;
+      env->gc_count++;
+    }
+  }
+
+  env->gc_limit= env->gc_count+20;
+  env->gc_ref= new_head;
+}
+
 /* Push a value onto the stack */
 void push_val(environment *env, value *val)
 {
   stackitem *new_item= malloc(sizeof(stackitem));
   new_item->item= val;
-  val->refcount++;
   new_item->next= env->head;
   env->head= new_item;
 }
@@ -168,11 +194,10 @@
 /* Push an integer onto the stack. */
 void push_int(environment *env, int in_val) 
 {
-  value *new_value= malloc(sizeof(value));
+  value *new_value= new_val(env);
   
   new_value->content.val= in_val;
   new_value->type= integer;
-  new_value->refcount=1;
 
   push_val(env, new_value);
 }
@@ -180,12 +205,11 @@
 /* Copy a string onto the stack. */
 void push_cstring(environment *env, const char *in_string)
 {
-  value *new_value= malloc(sizeof(value));
+  value *new_value= new_val(env);
 
   new_value->content.ptr= malloc(strlen(in_string)+1);
   strcpy(new_value->content.ptr, in_string);
   new_value->type= string;
-  new_value->refcount=1;
 
   push_val(env, new_value);
 }
@@ -211,7 +235,6 @@
 }
 
 extern void mangle(environment *env){
-  value *new_value;
   char *new_string;
 
   if((env->head)==NULL) {
@@ -231,12 +254,7 @@
   toss(env);
   if(env->err) return;
 
-  new_value= malloc(sizeof(value));
-  new_value->content.ptr= new_string;
-  new_value->type= string;
-  new_value->refcount=1;
-
-  push_val(env, new_value);
+  push_cstring(env, new_string);
 }
 
 /* Push a symbol onto the stack. */
@@ -254,11 +272,10 @@
   const char *dlerr;		/* Dynamic linker error */
   char *mangled;		/* Mangled function name */
 
-  new_value= malloc(sizeof(value));
+  new_value= new_val(env);
 
   /* The new value is a symbol */
   new_value->type= symb;
-  new_value->refcount= 1;
 
   /* Look up the symbol name in the hash table */
   new_symbol= hash(env->symbols, in_string);
@@ -281,21 +298,20 @@
     if(handle==NULL)		/* If no handle */
       handle= dlopen(NULL, RTLD_LAZY);
 
-    funcptr= dlsym(handle, in_string); /* Get function pointer */
+    mangled=mangle_str(in_string); /* mangle the name */
+    funcptr= dlsym(handle, mangled); /* and try to find it */
+    free(mangled);
     dlerr=dlerror();
     if(dlerr != NULL) {		/* If no function was found */
-      mangled=mangle_str(in_string);
-      funcptr= dlsym(handle, mangled); /* try mangling it */
-      free(mangled);
+      funcptr= dlsym(handle, in_string); /* Get function pointer */
       dlerr=dlerror();
     }
     if(dlerr==NULL) {		/* If a function was found */
-      new_fvalue= malloc(sizeof(value)); /* Create a new value */
+      new_fvalue= new_val(env); /* Create a new value */
       new_fvalue->type=func;	/* The new value is a function pointer */
       new_fvalue->content.ptr=funcptr; /* Store function pointer */
       (*new_symbol)->val= new_fvalue; /* Bind the symbol to the new
                                          function value */
-      new_fvalue->refcount= 1;
     }
   }
   push_val(env, new_value);
@@ -338,14 +354,17 @@
 }    
 
 /* Prints the top element of the stack. */
-void print_h(stackitem *stack_head)
+void print_h(stackitem *stack_head, int noquote)
 {
   switch(stack_head->item->type) {
   case integer:
     printf("%d", stack_head->item->content.val);
     break;
   case string:
-    printf("%s", (char*)stack_head->item->content.ptr);
+    if(noquote)
+      printf("%s", (char*)stack_head->item->content.ptr);
+    else
+      printf("\"%s\"", (char*)stack_head->item->content.ptr);
     break;
   case symb:
     printf("%s", ((symbol *)(stack_head->item->content.ptr))->id);
@@ -358,7 +377,7 @@
     stack_head=(stackitem *)(stack_head->item->content.ptr);
     printf("[ ");
     while(stack_head != NULL) {
-      print_h(stack_head);
+      print_h(stack_head, noquote);
       printf(" ");
       stack_head=stack_head->next;
     }
@@ -373,7 +392,8 @@
     env->err=1;
     return;
   }
-  print_h(env->head);
+  print_h(env->head, 0);
+  nl();
 }
 
 /* Prints the top element of the stack and then discards it. */
@@ -384,13 +404,30 @@
   toss(env);
 }
 
+extern void princ_(environment *env) {
+  if(env->head==NULL) {
+    printerr("Too Few Arguments");
+    env->err=1;
+    return;
+  }
+  print_h(env->head, 1);
+}
+
+/* Prints the top element of the stack and then discards it. */
+extern void princ(environment *env)
+{
+  princ_(env);
+  if(env->err) return;
+  toss(env);
+}
+
 /* 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_h(stack_head);
+  print_h(stack_head, 0);
   nl();
 }
 
@@ -398,10 +435,10 @@
 extern void printstack(environment *env)
 {
   if(env->head == NULL) {
+    printf("Stack Empty\n");
     return;
   }
   print_st(env->head, 1);
-  nl();
 }
 
 /* Swap the two top elements on the stack. */
@@ -474,14 +511,14 @@
   value* temp_val;
   stackitem* iterator;
 
+ eval_start:
+
   if(env->head==NULL) {
     printerr("Too Few Arguments");
     env->err=1;
     return;
   }
 
- eval_start:
-
   switch(env->head->item->type) {
     /* if it's a symbol */
   case symb:
@@ -502,7 +539,6 @@
     /* If it's a list */
   case list:
     temp_val= env->head->item;
-    env->head->item->refcount++;
     toss(env);
     if(env->err) return;
     iterator= (stackitem*)temp_val->content.ptr;
@@ -513,7 +549,6 @@
 	toss(env);
 	if(env->err) return;
 	if(iterator->next == NULL){
-	  free_val(temp_val);
 	  goto eval_start;
 	}
 	eval(env);
@@ -521,7 +556,6 @@
       }
       iterator= iterator->next;
     }
-    free_val(temp_val);
     return;
 
   default:
@@ -586,10 +620,9 @@
   }
 
   /* Push list */
-  pack= malloc(sizeof(value));
+  pack= new_val(env);
   pack->type= list;
   pack->content.ptr= temp;
-  pack->refcount= 1;
 
   push_val(env, pack);
   rev(env);
@@ -620,7 +653,6 @@
   /* The first list element is the new stack head */
   new_head= temp= env->head->item->content.ptr;
 
-  env->head->item->refcount++;
   toss(env);
 
   /* Find the end of the list */
@@ -706,12 +738,9 @@
   sym=env->head->item->content.ptr;
 
   /* if the symbol was bound to something else, throw it away */
-  if(sym->val != NULL)
-    free_val(sym->val);
 
   /* Bind the symbol to the value */
   sym->val= env->head->next->item;
-  sym->val->refcount++;		/* Increase the reference counter */
 
   toss(env); toss(env);
 } 
@@ -719,6 +748,25 @@
 /* Quit stack. */
 extern void quit(environment *env)
 {
+  long i;
+
+  clear(env);
+
+  if (env->err) return;
+  for(i= 0; i<HASHTBLSIZE; i++) {
+    while(env->symbols[i]!= NULL) {
+      forget_sym(&(env->symbols[i]));
+    }
+    env->symbols[i]= NULL;
+  }
+
+  gc_init(env);
+
+  if(env->free_string!=NULL)
+    free(env->free_string);
+  
+  muntrace();
+
   exit(EXIT_SUCCESS);
 }
 
@@ -744,12 +792,22 @@
   }
 }
 
+/* Internal forget function */
+void forget_sym(symbol **hash_entry) {
+  symbol *temp;
+
+  temp= *hash_entry;
+  *hash_entry= (*hash_entry)->next;
+  
+  free(temp->id);
+  free(temp);
+}
+
 /* Forgets a symbol (remove it from the hash table) */
 extern void forget(environment *env)
 {
   char* sym_id;
   stackitem *stack_head= env->head;
-  symbol **hash_entry, *temp;
 
   if(stack_head==NULL) {
     printerr("Too Few Arguments");
@@ -766,15 +824,7 @@
   sym_id= ((symbol*)(stack_head->item->content.ptr))->id;
   toss(env);
 
-  hash_entry= hash(env->symbols, sym_id);
-  temp= *hash_entry;
-  *hash_entry= (*hash_entry)->next;
-  
-  if(temp->val!=NULL) {
-    free_val(temp->val);
-  }
-  free(temp->id);
-  free(temp);
+  return forget_sym(hash(env->symbols, sym_id));
 }
 
 /* Returns the current error number to the stack */
@@ -782,21 +832,57 @@
   push_int(env, env->err);
 }
 
-extern void read(environment*);
-
-int main()
+int main(int argc, char **argv)
 {
   environment myenv;
 
+  int c;			/* getopt option character */
+
+  mtrace();
+
   init_env(&myenv);
 
+  myenv.interactive = isatty(STDIN_FILENO) && isatty(STDOUT_FILENO);
+
+  while ((c = getopt (argc, argv, "i")) != -1)
+    switch (c)
+      {
+      case 'i':
+	myenv.interactive = 1;
+	break;
+      case '?':
+	fprintf (stderr,
+		 "Unknown option character `\\x%x'.\n",
+		 optopt);
+	return EX_USAGE;
+      default:
+	abort ();
+      }
+  
+  if (optind < argc) {
+    myenv.interactive = 0;
+    myenv.inputstream= fopen(argv[optind], "r");
+    if(myenv.inputstream== NULL) {
+      perror(argv[0]);
+      exit (EX_NOINPUT);
+    }
+  }
+
   while(1) {
-    if(myenv.in_string==NULL)
-      printstack(&myenv);
-    read(&myenv);
-    if(myenv.err) {
-      printf("(error %d) ", myenv.err);
+    if(myenv.in_string==NULL) {
+      if (myenv.interactive) {
+	if(myenv.err) {
+	  printf("(error %d)\n", myenv.err);
+	}
+	nl();
+	printstack(&myenv);
+	printf("> ");
+      }
       myenv.err=0;
+    }
+    sx_72656164(&myenv);
+    if (myenv.err==4) {
+      return EX_NOINPUT;
     } else if(myenv.head!=NULL
 	      && myenv.head->item->type==symb
 	      && ((symbol*)(myenv.head->item->content.ptr))->id[0]==';') {
@@ -808,7 +894,7 @@
   return EXIT_FAILURE;
 }
 
-/* + */
+/* "+" */
 extern void sx_2b(environment *env) {
   int a, b;
   size_t len;
@@ -825,15 +911,12 @@
      && env->head->next->item->type==string) {
     a_val= env->head->item;
     b_val= env->head->next->item;
-    a_val->refcount++;
-    b_val->refcount++;
     toss(env); if(env->err) return;
     toss(env); if(env->err) return;
     len= strlen(a_val->content.ptr)+strlen(b_val->content.ptr)+1;
     new_string= malloc(len);
     strcpy(new_string, b_val->content.ptr);
     strcat(new_string, a_val->content.ptr);
-    free_val(a_val); free_val(b_val);
     push_cstring(env, new_string);
     free(new_string);
     return;
@@ -846,19 +929,14 @@
     return;
   }
   a=env->head->item->content.val;
-  toss(env);
-  if(env->err) return;
-  if(env->head->item->refcount == 1)
-    env->head->item->content.val += a;
-  else {
-    b=env->head->item->content.val;
-    toss(env);
-    if(env->err) return;
-    push_int(env, a+b);
-  }
+  toss(env); if(env->err) return;
+  
+  b=env->head->item->content.val;
+  toss(env); if(env->err) return;
+  push_int(env, a+b);
 }
 
-/* - */
+/* "-" */
 extern void sx_2d(environment *env) {
   int a, b;
 
@@ -875,19 +953,13 @@
     return;
   }
   a=env->head->item->content.val;
-  toss(env);
-  if(env->err) return;
-  if(env->head->item->refcount == 1)
-    env->head->item->content.val -= a;
-  else {
-    b=env->head->item->content.val;
-    toss(env);
-    if(env->err) return;
-    push_int(env, b-a);
-  }
+  toss(env); if(env->err) return;
+  b=env->head->item->content.val;
+  toss(env); if(env->err) return;
+  push_int(env, b-a);
 }
 
-/* > */
+/* ">" */
 extern void sx_3e(environment *env) {
   int a, b;
 
@@ -904,28 +976,20 @@
     return;
   }
   a=env->head->item->content.val;
-  toss(env);
-  if(env->err) return;
-  if(env->head->item->refcount == 1)
-    env->head->item->content.val = (env->head->item->content.val > a);
-  else {
-    b=env->head->item->content.val;
-    toss(env);
-    if(env->err) return;
-    push_int(env, b>a);
-  }
+  toss(env); if(env->err) return;
+  b=env->head->item->content.val;
+  toss(env); if(env->err) return;
+  push_int(env, b>a);
 }
 
 /* Return copy of a value */
-value *copy_val(value *old_value){
+value *copy_val(environment *env, value *old_value){
   stackitem *old_item, *new_item, *prev_item;
 
-  value *new_value=malloc(sizeof(value));
+  value *new_value=new_val(env);
 
   new_value->type=old_value->type;
-  new_value->refcount=0;	/* This is increased if/when this
-				   value is referenced somewhere, like
-				   in a stack item or a variable */
+
   switch(old_value->type){
   case integer:
     new_value->content.val=old_value->content.val;
@@ -946,7 +1010,7 @@
 
     while(old_item != NULL) {	/* While list is not empty */
       new_item= malloc(sizeof(stackitem));
-      new_item->item=copy_val(old_item->item); /* recurse */
+      new_item->item=copy_val(env, old_item->item); /* recurse */
       new_item->next=NULL;
       if(prev_item != NULL)	/* If this wasn't the first item */
 	prev_item->next=new_item; /* point the previous item to the
@@ -961,14 +1025,14 @@
   return new_value;
 }
 
-/* duplicates an item on the stack */
-extern void dup(environment *env) {
+/* "dup"; duplicates an item on the stack */
+extern void sx_647570(environment *env) {
   if((env->head)==NULL) {
     printerr("Too Few Arguments");
     env->err=1;
     return;
   }
-  push_val(env, copy_val(env->head->item));
+  push_val(env, copy_val(env, env->head->item));
 }
 
 /* "if", If-Then */
@@ -1038,7 +1102,7 @@
   eval(env);
 }
 
-/* while */
+/* "while" */
 extern void sx_7768696c65(environment *env) {
 
   int truth;
@@ -1051,11 +1115,9 @@
   }
 
   loop= env->head->item;
-  loop->refcount++;
   toss(env); if(env->err) return;
 
   test= env->head->item;
-  test->refcount++;
   toss(env); if(env->err) return;
 
   do {
@@ -1079,12 +1141,9 @@
     }
   
   } while(truth);
-
-  free_val(test);
-  free_val(loop);
 }
 
-/* For-loop */
+/* "for"; For-loop */
 extern void sx_666f72(environment *env) {
   
   value *loop, *foo;
@@ -1103,11 +1162,9 @@
   }
 
   loop= env->head->item;
-  loop->refcount++;
   toss(env); if(env->err) return;
 
   foo= env->head->item;
-  foo->refcount++;
   toss(env); if(env->err) return;
 
   iterator= foo->content.ptr;
@@ -1118,12 +1175,9 @@
     eval(env); if(env->err) return;
     iterator= iterator->next;
   }
-
-  free_val(loop);
-  free_val(foo);
 }
 
-/* 'to' */
+/* "to" */
 extern void to(environment *env) {
   int i, start, ending;
   stackitem *temp_head;
@@ -1158,9 +1212,8 @@
       push_int(env, i);
   }
 
-  temp_val= malloc(sizeof(value));
+  temp_val= new_val(env);
   temp_val->content.ptr= env->head;
-  temp_val->refcount= 1;
   temp_val->type= list;
   env->head= temp_head;
   push_val(env, temp_val);
@@ -1170,63 +1223,80 @@
 extern void readline(environment *env) {
   char in_string[101];
 
-  fgets(in_string, 100, stdin);
-  push_cstring(env, in_string);
+  if(fgets(in_string, 100, env->inputstream)==NULL)
+    push_cstring(env, "");
+  else
+    push_cstring(env, in_string);
 }
 
-/* Read a value and place on stack */
-extern void read(environment *env) {
-  const char symbform[]= "%[a-zA-Z0-9!$%*+./:<=>?@^_~-]%[\001-\377]";
-  const char strform[]= "\"%[^\"]\"%[\001-\377]";
-  const char intform[]= "%i%[\001-\377]";
-  const char blankform[]= "%*[ \t]%[\001-\377]";
-  const char ebrackform[]= "%*1[]]%[\001-\377]";
-  const char semicform[]= "%*1[;]%[\001-\377]";
-  const char bbrackform[]= "%*1[[]%[\001-\377]";
+/* "read"; Read a value and place on stack */
+extern void sx_72656164(environment *env) {
+  const char symbform[]= "%[a-zA-Z0-9!$%*+./:<=>?@^_~-]%n";
+  const char strform[]= "\"%[^\"]\"%n";
+  const char intform[]= "%i%n";
+  const char blankform[]= "%*[ \t]%n";
+  const char ebrackform[]= "%*1[]]%n";
+  const char semicform[]= "%*1[;]%n";
+  const char bbrackform[]= "%*1[[]%n";
 
-  int itemp;
+  int itemp, readlength= -1;
   static int depth= 0;
-  char *rest, *match;
+  char *match;
   size_t inlength;
 
   if(env->in_string==NULL) {
+    if(depth > 0 && env->interactive) {
+      printf("]> ");
+    }
     readline(env); if(env->err) return;
+
+    if(((char *)(env->head->item->content.ptr))[0]=='\0'){
+      env->err= 4;		/* "" means EOF */
+      return;
+    }
     
     env->in_string= malloc(strlen(env->head->item->content.ptr)+1);
+    env->free_string= env->in_string; /* Save the original pointer */
     strcpy(env->in_string, env->head->item->content.ptr);
     toss(env); if(env->err) return;
   }
   
   inlength= strlen(env->in_string)+1;
   match= malloc(inlength);
-  rest= malloc(inlength);
 
-  if(sscanf(env->in_string, blankform, rest)) {
+  if(sscanf(env->in_string, blankform, &readlength)!=EOF
+     && readlength != -1) {
     ; 
-  } else if(sscanf(env->in_string, intform, &itemp, rest) > 0) {
+  } else if(sscanf(env->in_string, intform, &itemp, &readlength) != EOF
+	    && readlength != -1) {
     push_int(env, itemp);
-  } else if(sscanf(env->in_string, strform, match, rest) > 0) {
+  } else if(sscanf(env->in_string, strform, match, &readlength) != EOF
+	    && readlength != -1) {
     push_cstring(env, match);
-  } else if(sscanf(env->in_string, symbform, match, rest) > 0) {
+  } else if(sscanf(env->in_string, symbform, match, &readlength) != EOF
+	    && readlength != -1) {
     push_sym(env, match);
-  } else if(sscanf(env->in_string, ebrackform, rest) > 0) {
+  } else if(sscanf(env->in_string, ebrackform, &readlength) != EOF
+	    && readlength != -1) {
     pack(env); if(env->err) return;
-    if(depth!=0) depth--;
-  } else if(sscanf(env->in_string, semicform, rest) > 0) {
+    if(depth != 0) depth--;
+  } else if(sscanf(env->in_string, semicform, &readlength) != EOF
+	    && readlength != -1) {
     push_sym(env, ";");
-  } else if(sscanf(env->in_string, bbrackform, rest) > 0) {
+  } else if(sscanf(env->in_string, bbrackform, &readlength) != EOF
+	    && readlength != -1) {
     push_sym(env, "[");
     depth++;
   } else {
-    free(rest);
-    rest= NULL;
+    free(env->free_string);
+    env->in_string = env->free_string = NULL;
+  }
+  if ( env->in_string != NULL) {
+    env->in_string += readlength;
   }
-      
-  free(env->in_string);
-  free(match);
 
-  env->in_string= rest;
+  free(match);
 
   if(depth)
-    return read(env);
+    return sx_72656164(env);
 }