--- stack/stack.c	2002/02/14 12:20:09	1.80
+++ stack/stack.c	2002/03/07 01:21:07	1.90
@@ -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>
@@ -8,110 +8,39 @@
 #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 */
-  char *free_string;		/* Free this string when all input is
-                                   read from in_string */
-} 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->gc_ref= NULL;
+  env->gc_protect= NULL;
+
+  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)
 {
@@ -119,13 +48,14 @@
 
   if((env->head)==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     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 */
+
+  gc_init(env);
 }
 
 /* Returns a pointer to a pointer to an element in the hash table. */
@@ -157,12 +87,136 @@
   }
 }
 
+value* new_val(environment *env) {
+  value *nval= malloc(sizeof(value));
+  stackitem *nitem= malloc(sizeof(stackitem));
+
+  nval->content.ptr= NULL;
+  protect(env, nval);
+
+  gc_init(env);
+
+  nitem->item= nval;
+  nitem->next= env->gc_ref;
+  env->gc_ref= nitem;
+
+  env->gc_count++;
+  unprotect(env);
+
+  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;
+
+  if(env->gc_count < env->gc_limit)
+    return;
+
+  while(iterator!=NULL) {
+    iterator->item->gc_garb= 1;
+    iterator= iterator->next;
+  }
+
+  /* Mark */
+  iterator= env->gc_protect;
+  while(iterator!=NULL) {
+    gc_mark(iterator->item);
+    iterator= iterator->next;
+  }
+
+  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*2;
+  env->gc_ref= new_head;
+}
+
+void protect(environment *env, value *val)
+{
+  stackitem *new_item= malloc(sizeof(stackitem));
+  new_item->item= val;
+  new_item->next= env->gc_protect;
+  env->gc_protect= new_item;
+}
+
+void unprotect(environment *env)
+{
+  stackitem *temp= env->gc_protect;
+  env->gc_protect= env->gc_protect->next;
+  free(temp);
+}
+
 /* 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;
 }
@@ -170,11 +224,10 @@
 /* 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);
 }
@@ -182,49 +235,46 @@
 /* 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);
 }
 
 /* Mangle a symbol name to a valid C identifier name */
 char *mangle_str(const char *old_string){
-  char validchars[]
-    ="0123456789abcdef";
+  char validchars[]= "0123456789abcdef";
   char *new_string, *current;
 
-  new_string=malloc((strlen(old_string)*2)+4);
+  new_string= malloc((strlen(old_string)*2)+4);
   strcpy(new_string, "sx_");	/* Stack eXternal */
-  current=new_string+3;
+  current= new_string+3;
   while(old_string[0] != '\0'){
-    current[0]=validchars[(unsigned char)(old_string[0])/16];
-    current[1]=validchars[(unsigned char)(old_string[0])%16];
-    current+=2;
+    current[0]= validchars[(unsigned char)(old_string[0])/16];
+    current[1]= validchars[(unsigned char)(old_string[0])%16];
+    current+= 2;
     old_string++;
   }
-  current[0]='\0';
+  current[0]= '\0';
 
   return new_string;		/* The caller must free() it */
 }
 
 extern void mangle(environment *env){
-  value *new_value;
   char *new_string;
 
   if((env->head)==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
   if(env->head->item->type!=string) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
@@ -233,12 +283,7 @@
   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. */
@@ -256,11 +301,10 @@
   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);
@@ -283,21 +327,20 @@
     if(handle==NULL)		/* If no handle */
       handle= dlopen(NULL, RTLD_LAZY);
 
-    funcptr= dlsym(handle, in_string); /* Get function pointer */
-    dlerr=dlerror();
+    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);
-      dlerr=dlerror();
+      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->type=func;	/* The new value is a function pointer */
-      new_fvalue->content.ptr=funcptr; /* Store function pointer */
+      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);
@@ -483,9 +526,11 @@
     env->err=3;
     return;
   }
+  protect(env, val);
   toss(env);		/* toss the symbol */
   if(env->err) return;
   push_val(env, val); /* Return its bound value */
+  unprotect(env);
 }
 
 /* If the top element is a symbol, determine if it's bound to a
@@ -520,23 +565,26 @@
     in_func= (funcp)(env->head->item->content.ptr);
     toss(env); 
     if(env->err) return;
-    return (*in_func)(env);
+    return in_func(env);
 
     /* If it's a list */
   case list:
     temp_val= env->head->item;
-    env->head->item->refcount++;
+    protect(env, temp_val);
     toss(env);
     if(env->err) return;
     iterator= (stackitem*)temp_val->content.ptr;
+    unprotect(env);
+    
     while(iterator!=NULL) {
       push_val(env, iterator->item);
+      
       if(env->head->item->type==symb
 	&& strcmp(";", ((symbol*)(env->head->item->content.ptr))->id)==0) {
 	toss(env);
 	if(env->err) return;
+	
 	if(iterator->next == NULL){
-	  free_val(temp_val);
 	  goto eval_start;
 	}
 	eval(env);
@@ -544,7 +592,6 @@
       }
       iterator= iterator->next;
     }
-    free_val(temp_val);
     return;
 
   default:
@@ -558,25 +605,25 @@
 
   if((env->head)==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
   if(env->head->item->type!=list) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
-  old_head=(stackitem *)(env->head->item->content.ptr);
-  new_head=NULL;
+  old_head= (stackitem *)(env->head->item->content.ptr);
+  new_head= NULL;
   while(old_head != NULL){
-    item=old_head;
-    old_head=old_head->next;
-    item->next=new_head;
-    new_head=item;
+    item= old_head;
+    old_head= old_head->next;
+    item->next= new_head;
+    new_head= item;
   }
-  env->head->item->content.ptr=new_head;
+  env->head->item->content.ptr= new_head;
 }
 
 /* Make a list. */
@@ -609,10 +656,9 @@
   }
 
   /* 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);
@@ -626,12 +672,12 @@
   /* Is top element a list? */
   if(env->head==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
   if(env->head->item->type!=list) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
@@ -643,7 +689,6 @@
   /* 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 */
@@ -664,7 +709,7 @@
 
   if((env->head)==NULL || env->head->next==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
@@ -684,13 +729,13 @@
 
   if((env->head)==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
   if(env->head->item->type!=integer) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
@@ -715,39 +760,32 @@
   /* Needs two values on the stack, the top one must be a symbol */
   if(env->head==NULL || env->head->next==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
   if(env->head->item->type!=symb) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
   /* long names are a pain */
-  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);
+  sym= env->head->item->content.ptr;
 
   /* Bind the symbol to the value */
   sym->val= env->head->next->item;
-  sym->val->refcount++;		/* Increase the reference counter */
 
   toss(env); toss(env);
 } 
 
-extern void clear(environment *);
-void forget_sym(symbol **);
-
 /* 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) {
@@ -755,6 +793,15 @@
     }
     env->symbols[i]= NULL;
   }
+
+  env->gc_limit= 0;
+  gc_init(env);
+
+  if(env->free_string!=NULL)
+    free(env->free_string);
+  
+  muntrace();
+
   exit(EXIT_SUCCESS);
 }
 
@@ -787,9 +834,6 @@
   temp= *hash_entry;
   *hash_entry= (*hash_entry)->next;
   
-  if(temp->val!=NULL) {
-    free_val(temp->val);
-  }
   free(temp->id);
   free(temp);
 }
@@ -823,36 +867,70 @@
   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) {
-      nl();
-      printstack(&myenv);
-      printf("> ");
-    }
-    read(&myenv);
-    if(myenv.err) {
-      printf("(error %d) ", myenv.err);
+      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]==';') {
       toss(&myenv); 		/* No error check in main */
       eval(&myenv);
     }
+    gc_init(&myenv);
   }
   quit(&myenv);
   return EXIT_FAILURE;
 }
 
-/* + */
+/* "+" */
 extern void sx_2b(environment *env) {
   int a, b;
   size_t len;
@@ -861,7 +939,7 @@
 
   if((env->head)==NULL || env->head->next==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
@@ -869,16 +947,15 @@
      && env->head->next->item->type==string) {
     a_val= env->head->item;
     b_val= env->head->next->item;
-    a_val->refcount++;
-    b_val->refcount++;
+    protect(env, a_val); protect(env, 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;
     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);
+    unprotect(env); unprotect(env);
     free(new_string);
     return;
   }
@@ -889,20 +966,15 @@
     env->err=2;
     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);
-  }
+  a= env->head->item->content.val;
+  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;
 
@@ -918,20 +990,15 @@
     env->err=2;
     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;
 
@@ -947,72 +1014,69 @@
     env->err=2;
     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);
+
+  protect(env, old_value);
+  new_value->type= old_value->type;
 
-  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;
+    new_value->content.val= old_value->content.val;
     break;
   case string:
-    (char *)(new_value->content.ptr)
-      = strdup((char *)(old_value->content.ptr));
+    (char *)(new_value->content.ptr)= 
+      strdup((char *)(old_value->content.ptr));
     break;
   case func:
   case symb:
-    new_value->content.ptr=old_value->content.ptr;
+    new_value->content.ptr= old_value->content.ptr;
     break;
   case list:
-    new_value->content.ptr=NULL;
+    new_value->content.ptr= NULL;
 
-    prev_item=NULL;
-    old_item=(stackitem *)(old_value->content.ptr);
+    prev_item= NULL;
+    old_item= (stackitem*)(old_value->content.ptr);
 
     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->next=NULL;
+      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
+	prev_item->next= new_item; /* point the previous item to the
                                      new item */
       else
-	new_value->content.ptr=new_item;
-      old_item=old_item->next;
-      prev_item=new_item;
+	new_value->content.ptr= new_item;
+      old_item= old_item->next;
+      prev_item= new_item;
     }	  
     break;
   }
+
+  unprotect(env);
+
   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;
+    env->err= 1;
     return;
   }
-  push_val(env, copy_val(env->head->item));
+  push_val(env, copy_val(env, env->head->item));
 }
 
 /* "if", If-Then */
@@ -1022,7 +1086,7 @@
 
   if((env->head)==NULL || env->head->next==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
@@ -1082,7 +1146,7 @@
   eval(env);
 }
 
-/* while */
+/* "while" */
 extern void sx_7768696c65(environment *env) {
 
   int truth;
@@ -1095,11 +1159,11 @@
   }
 
   loop= env->head->item;
-  loop->refcount++;
+  protect(env, loop);
   toss(env); if(env->err) return;
 
   test= env->head->item;
-  test->refcount++;
+  protect(env, test);
   toss(env); if(env->err) return;
 
   do {
@@ -1108,7 +1172,7 @@
     
     if(env->head->item->type != integer) {
       printerr("Bad Argument Type");
-      env->err=2;
+      env->err= 2;
       return;
     }
     
@@ -1124,34 +1188,81 @@
   
   } while(truth);
 
-  free_val(test);
-  free_val(loop);
+  unprotect(env); unprotect(env);
 }
 
-/* For-loop */
+
+/* "for"; for-loop */
 extern void sx_666f72(environment *env) {
+  value *loop;
+  int foo1, foo2;
+
+  if(env->head==NULL || env->head->next==NULL 
+     || env->head->next->next==NULL) {
+    printerr("Too Few Arguments");
+    env->err= 1;
+    return;
+  }
+
+  if(env->head->next->item->type!=integer
+     || env->head->next->next->item->type!=integer) {
+    printerr("Bad Argument Type");
+    env->err= 2;
+    return;
+  }
+
+  loop= env->head->item;
+  protect(env, loop);
+  toss(env); if(env->err) return;
+
+  foo2= env->head->item->content.val;
+  toss(env); if(env->err) return;
+
+  foo1= env->head->item->content.val;
+  toss(env); if(env->err) return;
+
+  if(foo1<=foo2) {
+    while(foo1<=foo2) {
+      push_int(env, foo1);
+      push_val(env, loop);
+      eval(env); if(env->err) return;
+      foo1++;
+    }
+  } else {
+    while(foo1>=foo2) {
+      push_int(env, foo1);
+      push_val(env, loop);
+      eval(env); if(env->err) return;
+      foo1--;
+    }
+  }
+  unprotect(env);
+}
+
+/* Variant of for-loop */
+extern void foreach(environment *env) {
   
   value *loop, *foo;
   stackitem *iterator;
   
   if((env->head)==NULL || env->head->next==NULL) {
     printerr("Too Few Arguments");
-    env->err=1;
+    env->err= 1;
     return;
   }
 
   if(env->head->next->item->type != list) {
     printerr("Bad Argument Type");
-    env->err=2;
+    env->err= 2;
     return;
   }
 
   loop= env->head->item;
-  loop->refcount++;
+  protect(env, loop);
   toss(env); if(env->err) return;
 
   foo= env->head->item;
-  foo->refcount++;
+  protect(env, foo);
   toss(env); if(env->err) return;
 
   iterator= foo->content.ptr;
@@ -1162,12 +1273,10 @@
     eval(env); if(env->err) return;
     iterator= iterator->next;
   }
-
-  free_val(loop);
-  free_val(foo);
+  unprotect(env); unprotect(env);
 }
 
-/* 'to' */
+/* "to" */
 extern void to(environment *env) {
   int i, start, ending;
   stackitem *temp_head;
@@ -1202,9 +1311,8 @@
       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);
@@ -1214,30 +1322,37 @@
 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) {
+/* "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";
+  const char ebrackform[]= "]%n";
+  const char semicform[]= ";%n";
+  const char bbrackform[]= "[%n";
 
   int itemp, readlength= -1;
   static int depth= 0;
-  char *rest, *match;
+  char *match;
   size_t inlength;
 
   if(env->in_string==NULL) {
-    if(depth > 0) {
+    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 */
@@ -1247,7 +1362,6 @@
   
   inlength= strlen(env->in_string)+1;
   match= malloc(inlength);
-  rest= malloc(inlength);
 
   if(sscanf(env->in_string, blankform, &readlength)!=EOF
      && readlength != -1) {
@@ -1275,12 +1389,13 @@
   } else {
     free(env->free_string);
     env->in_string = env->free_string = NULL;
-    free(match);
   }
   if ( env->in_string != NULL) {
     env->in_string += readlength;
   }
 
+  free(match);
+
   if(depth)
-    return read(env);
+    return sx_72656164(env);
 }