--- stack/stack.c	2002/03/10 12:05:20	1.100
+++ stack/stack.c	2003/08/18 14:39:16	1.136
@@ -1,3 +1,4 @@
+/* -*- coding: utf-8; -*- */
 /*
     stack - an interactive interpreter for a stack-based language
     Copyright (C) 2002	Mats Alritzson and Teddy Hogeborn
@@ -20,29 +21,15 @@
 	     Teddy Hogeborn <teddy@fukt.bth.se>
 */
 
-/* printf, sscanf, fgets, fprintf, fopen, perror */
-#include <stdio.h>
-/* exit, EXIT_SUCCESS, malloc, free */
-#include <stdlib.h>
-/* NULL */
-#include <stddef.h>
-/* dlopen, dlsym, dlerror */
-#include <dlfcn.h>
-/* strcmp, strcpy, strlen, strcat, strdup */
-#include <string.h>
-/* getopt, STDIN_FILENO, STDOUT_FILENO, usleep */
-#include <unistd.h>
-/* EX_NOINPUT, EX_USAGE */
-#include <sysexits.h>
-/* mtrace, muntrace */
-#include <mcheck.h>
-/* ioctl */
-#include <sys/ioctl.h>
-/* KDMKTONE */
-#include <linux/kd.h>
-
 #include "stack.h"
 
+const char* start_message= "Stack version $Revision: 1.136 $\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\
+under certain conditions; type 'copying;' for details.";
+
+
 /* Initialize a newly created environment */
 void init_env(environment *env)
 {
@@ -52,7 +39,7 @@
   env->gc_count= 0;
   env->gc_ref= NULL;
 
-  env->head= NULL;
+  env->head= new_val(env);
   for(i= 0; i<HASHTBLSIZE; i++)
     env->symbols[i]= NULL;
   env->err= 0;
@@ -62,26 +49,34 @@
   env->interactive= 1;
 }
 
-void printerr(const char* in_string)
-{
-  fprintf(stderr, "Err: %s\n", in_string);
-}
 
-/* Discard the top element of the stack. */
-extern void toss(environment *env)
+void printerr(environment *env)
 {
-  stackitem *temp= env->head;
+  char *in_string;
 
-  if((env->head)==NULL) {
-    printerr("Too Few Arguments");
-    env->err= 1;
+  switch(env->err) {
+  case 0:
     return;
+  case 1:
+    in_string= "Too Few Arguments";
+    break;
+  case 2:
+    in_string= "Bad Argument Type";
+    break;
+  case 3:
+    in_string= "Unbound Variable";
+    break;
+  case 5:
+    return perror(env->errsymb);
+  default:
+    in_string= "Unknown error";
+    break;
   }
-  
-  env->head= env->head->next;	/* Remove the top stack item */
-  free(temp);			/* Free the old top stack item */
+
+  fprintf(stderr, "\"%s\":\nErr: %s\n", env->errsymb, in_string);
 }
 
+
 /* Returns a pointer to a pointer to an element in the hash table. */
 symbol **hash(hashtbl in_hashtbl, const char *in_string)
 {
@@ -111,118 +106,135 @@
   }
 }
 
+
 /* Create new value */
 value* new_val(environment *env)
 {
   value *nval= malloc(sizeof(value));
   stackitem *nitem= malloc(sizeof(stackitem));
 
+  assert(nval != NULL);
+  assert(nitem != NULL);
+
   nval->content.ptr= NULL;
+  nval->type= empty;
 
   nitem->item= nval;
   nitem->next= env->gc_ref;
+
   env->gc_ref= nitem;
 
-  env->gc_count+=sizeof(value);
+  env->gc_count += sizeof(value);
   nval->gc.flag.mark= 0;
   nval->gc.flag.protect= 0;
 
   return nval;
 }
 
+
 /* Mark values recursively. 
    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) {
+    gc_mark(CAR(val));
+    gc_mark(CDR(val));
   }
 }
 
-inline void gc_maybe(environment *env)
-{
-  if(env->gc_count < env->gc_limit)
-    return;
-  else
-    return gc_init(env);
-}
 
 /* Start GC */
 extern void gc_init(environment *env)
 {
-  stackitem *new_head= NULL, *titem, *iterator;
+  stackitem *new_head= NULL, *titem;
   symbol *tsymb;
   int i;
 
-  if(env->interactive){
-    printf("Garbage collecting.", env->gc_count, env->gc_limit);
-  }
+  if(env->interactive)
+    printf("Garbage collecting.");
 
   /* Mark values on stack */
-  iterator= env->head;
-  while(iterator!=NULL) {
-    gc_mark(iterator->item);
-    iterator= iterator->next;
-  }
+  gc_mark(env->head);
 
-  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;
 
   while(env->gc_ref!=NULL) {	/* Sweep unused values */
-
     if(!(env->gc_ref->item->gc.no_gc)){ /* neither mark nor protect */
 
-      switch(env->gc_ref->item->type) {	/* Remove content */
+      /* Remove content */
+      switch(env->gc_ref->item->type){
       case string:
-	free(env->gc_ref->item->content.ptr);
+	free(env->gc_ref->item->content.string);
+	break;
+      case tcons:
+	free(env->gc_ref->item->content.c);
+	break;
+      case port:
+      case empty:
+      case unknown:
+      case integer:
+      case tfloat:
+      case func:
+      case symb:
+	/* Symbol strings are freed when walking the hash table */
 	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);
     }
+
+#ifdef DEBUG
+    printf("Kept value (%p)", env->gc_ref->item);
+    if(env->gc_ref->item->gc.flag.mark)
+      printf(" (marked)");
+    if(env->gc_ref->item->gc.flag.protect)
+      printf(" (protected)");
+    switch(env->gc_ref->item->type){
+    case integer:
+      printf(" integer: %d", env->gc_ref->item->content.i);
+      break;
+    case func:
+      printf(" func: %p", env->gc_ref->item->content.func);
+      break;
+    case symb:
+      printf(" symb: %s", env->gc_ref->item->content.sym->id);
+      break;
+    case tcons:
+      printf(" tcons: %p\t%p", CAR(env->gc_ref->item),
+	     CDR(env->gc_ref->item));
+      break;
+    default:
+      printf(" <unknown %d>", (env->gc_ref->item->type));
+    }
+    printf("\n");
+#endif /* DEBUG */
+
+    /* Keep values */     
+    env->gc_count += sizeof(value);
+    if(env->gc_ref->item->type==string)
+      env->gc_count += strlen(env->gc_ref->item->content.string)+1;
     
-    /* Keep values */
     titem= env->gc_ref->next;
     env->gc_ref->next= new_head;
     new_head= env->gc_ref;
@@ -232,63 +244,69 @@
 
   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");
-  }
+  if(env->interactive)
+    printf("done (%d bytes still allocated)\n", env->gc_count);
 
 }
 
+
+inline void gc_maybe(environment *env)
+{
+  if(env->gc_count < env->gc_limit)
+    return;
+  else
+    return gc_init(env);
+}
+
+
 /* 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) {
+    protect(CAR(val));
+    protect(CDR(val));
   }
 }
 
+
 /* 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) {
+    unprotect(CAR(val));
+    unprotect(CDR(val));
   }
 }
 
+
 /* 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;
-  env->head= new_item;
+  value *new_value= new_val(env);
+
+  new_value->content.c= malloc(sizeof(pair));
+  assert(new_value->content.c!=NULL);
+  env->gc_count += sizeof(pair);
+  new_value->type= tcons;
+  CAR(new_value)= val;
+  CDR(new_value)= env->head;
+  env->head= new_value;
 }
 
+
 /* Push an integer onto the stack */
 void push_int(environment *env, int in_val) 
 {
@@ -300,6 +318,7 @@
   push_val(env, new_value);
 }
 
+
 /* Push a floating point number onto the stack */
 void push_float(environment *env, float in_val)
 {
@@ -311,18 +330,23 @@
   push_val(env, new_value);
 }
 
+
 /* Copy a string onto the stack. */
 void push_cstring(environment *env, const char *in_string)
 {
   value *new_value= new_val(env);
+  int length= strlen(in_string)+1;
 
-  new_value->content.ptr= malloc(strlen(in_string)+1);
-  strcpy(new_value->content.ptr, in_string);
+  new_value->content.string= malloc(length);
+  assert(new_value != NULL);
+  env->gc_count += length;
+  strcpy(new_value->content.string, in_string);
   new_value->type= string;
 
   push_val(env, new_value);
 }
 
+
 /* Mangle a symbol name to a valid C identifier name */
 char *mangle_str(const char *old_string)
 {
@@ -330,8 +354,10 @@
   char *new_string, *current;
 
   new_string= malloc((strlen(old_string)*2)+4);
+  assert(new_string != NULL);
   strcpy(new_string, "sx_");	/* Stack eXternal */
   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];
@@ -343,29 +369,6 @@
   return new_string;		/* The caller must free() it */
 }
 
-extern void mangle(environment *env)
-{
-  char *new_string;
-
-  if((env->head)==NULL) {
-    printerr("Too Few Arguments");
-    env->err= 1;
-    return;
-  }
-
-  if(env->head->item->type!=string) {
-    printerr("Bad Argument Type");
-    env->err= 2;
-    return;
-  }
-
-  new_string= mangle_str((const char *)(env->head->item->content.ptr));
-
-  toss(env);
-  if(env->err) return;
-
-  push_cstring(env, new_string);
-}
 
 /* Push a symbol onto the stack. */
 void push_sym(environment *env, const char *in_string)
@@ -383,28 +386,28 @@
   char *mangled;		/* Mangled function name */
 
   new_value= new_val(env);
-  protect(new_value);
   new_fvalue= new_val(env);
-  protect(new_fvalue);
 
   /* The new value is a symbol */
   new_value->type= symb;
 
   /* Look up the symbol name in the hash table */
   new_symbol= hash(env->symbols, in_string);
-  new_value->content.ptr= *new_symbol;
+  new_value->content.sym= *new_symbol;
 
   if(*new_symbol==NULL) { /* If symbol was undefined */
 
     /* Create a new symbol */
     (*new_symbol)= malloc(sizeof(symbol));
+    assert((*new_symbol) != NULL);
     (*new_symbol)->val= NULL;	/* undefined value */
     (*new_symbol)->next= NULL;
     (*new_symbol)->id= malloc(strlen(in_string)+1);
+    assert((*new_symbol)->id != NULL);
     strcpy((*new_symbol)->id, in_string);
 
     /* Intern the new symbol in the hash table */
-    new_value->content.ptr= *new_symbol;
+    new_value->content.sym= *new_symbol;
 
     /* Try to load the symbol name as an external function, to see if
        we should bind the symbol to a new function pointer value */
@@ -422,7 +425,7 @@
 
     if(dlerr==NULL) {		/* If a function was found */
       new_fvalue->type= func;	/* The new value is a function pointer */
-      new_fvalue->content.ptr= funcptr; /* Store function pointer */
+      new_fvalue->content.func= funcptr; /* Store function pointer */
       (*new_symbol)->val= new_fvalue; /* Bind the symbol to the new
                                          function value */
     }
@@ -431,206 +434,182 @@
   }
 
   push_val(env, new_value);
-  unprotect(new_value); unprotect(new_fvalue);
 }
 
-/* Print newline. */
-extern void nl()
-{
-  printf("\n");
-}
-
-/* Gets the type of a value */
-extern void type(environment *env)
-{
-  int typenum;
 
-  if((env->head)==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
-  typenum=env->head->item->type;
-  toss(env);
-  switch(typenum){
-  case integer:
-    push_sym(env, "integer");
-    break;
-  case tfloat:
-    push_sym(env, "float");
-    break;
-  case string:
-    push_sym(env, "string");
-    break;
-  case symb:
-    push_sym(env, "symbol");
-    break;
-  case func:
-    push_sym(env, "function");
+/* Print a value */
+void print_val(environment *env, value *val, int noquote, stackitem *stack, 
+	       FILE *stream)
+{
+  stackitem *titem, *tstack;
+  int depth;
+
+  switch(val->type) {
+  case empty:
+    if(fprintf(stream, "[]") < 0)
+      env->err= 5;
+    break;
+  case unknown:
+    if(fprintf(stream, "UNKNOWN") < 0)
+      env->err= 5;
     break;
-  case list:
-    push_sym(env, "list");
-    break;
-  }
-}    
-
-/* Prints the top element of the stack. */
-void print_h(stackitem *stack_head, int noquote)
-{
-  switch(stack_head->item->type) {
   case integer:
-    printf("%d", stack_head->item->content.i);
+    if(fprintf(stream, "%d", val->content.i) < 0)
+      env->err= 5;
     break;
   case tfloat:
-    printf("%f", stack_head->item->content.f);
+    if(fprintf(stream, "%f", val->content.f) < 0)
+      env->err= 5;
     break;
   case string:
-    if(noquote)
-      printf("%s", (char*)stack_head->item->content.ptr);
-    else
-      printf("\"%s\"", (char*)stack_head->item->content.ptr);
+    if(noquote){
+      if(fprintf(stream, "%s", val->content.string) < 0)
+	env->err= 5;
+    } else {			/* quote */
+      if(fprintf(stream, "\"%s\"", val->content.string) < 0)
+	env->err= 5;
+    }
     break;
   case symb:
-    printf("%s", ((symbol *)(stack_head->item->content.ptr))->id);
+    if(fprintf(stream, "%s", val->content.sym->id) < 0)
+      env->err= 5;
     break;
   case func:
-    printf("#<function %p>", (funcp)(stack_head->item->content.ptr));
-    break;
-  case list:
-    /* A list is just a stack, so make stack_head point to it */
-    stack_head=(stackitem *)(stack_head->item->content.ptr);
-    printf("[ ");
-    while(stack_head != NULL) {
-      print_h(stack_head, noquote);
-      printf(" ");
-      stack_head=stack_head->next;
-    }
-    printf("]");
+    if(fprintf(stream, "#<function %p>", val->content.func) < 0)
+      env->err= 5;
     break;
-  }
-}
-
-extern void print_(environment *env)
-{
-  if(env->head==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
-  print_h(env->head, 0);
-  nl();
-}
+  case port:
+    if(fprintf(stream, "#<port %p>", val->content.p) < 0)
+      env->err= 5;
+    break;
+  case tcons:
+    if(fprintf(stream, "[ ") < 0) {
+      env->err= 5;
+      return printerr(env);
+    }
+    tstack= stack;
+
+    do {
+      titem=malloc(sizeof(stackitem));
+      assert(titem != NULL);
+      titem->item=val;
+      titem->next=tstack;
+      tstack=titem;		/* Put it on the stack */
+      /* Search a stack of values being printed to see if we are already
+	 printing this value */
+      titem=tstack;
+      depth=0;
+
+      while(titem != NULL && titem->item != CAR(val)){
+	titem=titem->next;
+	depth++;
+      }
 
-/* Prints the top element of the stack and then discards it. */
-extern void print(environment *env)
-{
-  print_(env);
-  if(env->err) return;
-  toss(env);
-}
+      if(titem != NULL){	/* If we found it on the stack, */
+	if(fprintf(stream, "#%d#", depth) < 0){	/* print a depth reference */
+	  env->err= 5;
+	  free(titem);
+	  return printerr(env);
+	}
+      } else {
+	print_val(env, CAR(val), noquote, tstack, stream);
+      }
 
-extern void princ_(environment *env)
-{
-  if(env->head==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
-  print_h(env->head, 1);
-}
+      val= CDR(val);
+      switch(val->type){
+      case empty:
+	break;
+      case tcons:
+	/* Search a stack of values being printed to see if we are already
+	   printing this value */
+	titem=tstack;
+	depth=0;
+
+	while(titem != NULL && titem->item != val){
+	  titem=titem->next;
+	  depth++;
+	}
+	if(titem != NULL){	/* If we found it on the stack, */
+	  if(fprintf(stream, " . #%d#", depth) < 0){ /* print a depth reference */
+	    env->err= 5;
+	    printerr(env);
+	    goto printval_end;
+	  }
+	} else {
+	  if(fprintf(stream, " ") < 0){
+	    env->err= 5;
+	    printerr(env);
+	    goto printval_end;
+	  }
+	}
+	break;
+      default:
+	if(fprintf(stream, " . ") < 0){	/* Improper list */
+	  env->err= 5;
+	  printerr(env);
+	  goto printval_end;
+        }
+	print_val(env, val, noquote, tstack, stream);
+      }
+    } while(val->type == tcons && titem == NULL);
 
-/* Prints the top element of the stack and then discards it. */
-extern void princ(environment *env)
-{
-  princ_(env);
-  if(env->err) return;
-  toss(env);
-}
+  printval_end:
 
-/* 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, 0);
-  nl();
-}
+    titem=tstack;
+    while(titem != stack){
+      tstack=titem->next;
+      free(titem);
+      titem=tstack;
+    }
 
-/* Prints the stack. */
-extern void printstack(environment *env)
-{
-  if(env->head == NULL) {
-    printf("Stack Empty\n");
-    return;
+    if(! (env->err)){
+      if(fprintf(stream, " ]") < 0){
+	env->err= 5;
+      }
+    }
+    break;
   }
-
-  print_st(env->head, 1);
+  
+  if(env->err)
+    return printerr(env);
 }
 
+
 /* Swap the two top elements on the stack. */
 extern void swap(environment *env)
 {
-  stackitem *temp= env->head;
-  
-  if(env->head==NULL || env->head->next==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
-
-  env->head= env->head->next;
-  temp->next= env->head->next;
-  env->head->next= temp;
-} 
+  value *temp= env->head;
 
-/* Rotate the first three elements on the stack. */
-extern void rot(environment *env)
-{
-  stackitem *temp= env->head;
+  if(check_args(env, 2, unknown, unknown))
+    return printerr(env);
   
-  if(env->head==NULL || env->head->next==NULL
-      || env->head->next->next==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
+  env->head= CDR(env->head);
+  CDR(temp)= CDR(env->head);
+  CDR(env->head)= temp;
+} 
 
-  env->head= env->head->next->next;
-  temp->next->next= env->head->next;
-  env->head->next= temp;
-}
 
 /* Recall a value from a symbol, if bound */
 extern void rcl(environment *env)
 {
   value *val;
 
-  if(env->head == NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
+  if(check_args(env, 1, symb))
+    return printerr(env);
 
-  if(env->head->item->type!=symb) {
-    printerr("Bad Argument Type");
-    env->err=2;
-    return;
-  }
-
-  val=((symbol *)(env->head->item->content.ptr))->val;
+  val= CAR(env->head)->content.sym->val;
   if(val == NULL){
-    printerr("Unbound Variable");
-    env->err=3;
-    return;
+    env->err= 3;
+    return printerr(env);
   }
-  protect(val);
-  toss(env);		/* toss the symbol */
+
+  push_val(env, val);		/* Return the symbol's bound value */
+  swap(env);
   if(env->err) return;
-  push_val(env, val); /* Return its bound value */
-  unprotect(val);
+  env->head= CDR(env->head);
 }
 
+
 /* If the top element is a symbol, determine if it's bound to a
    function value, and if it is, toss the symbol and execute the
    function. */
@@ -638,299 +617,74 @@
 {
   funcp in_func;
   value* temp_val;
-  stackitem* iterator;
+  value* iterator;
 
  eval_start:
 
   gc_maybe(env);
 
-  if(env->head==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
+  if(check_args(env, 1, unknown))
+    return printerr(env);
 
-  switch(env->head->item->type) {
+  switch(CAR(env->head)->type) {
     /* if it's a symbol */
   case symb:
+    env->errsymb= CAR(env->head)->content.sym->id;
     rcl(env);			/* get its contents */
     if(env->err) return;
-    if(env->head->item->type!=symb){ /* don't recurse symbols */
+    if(CAR(env->head)->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);
-    toss(env); 
-    if(env->err) return;
-    return in_func(env);
+    in_func= CAR(env->head)->content.func;
+    env->head= CDR(env->head);
+    return in_func((void*)env);
 
     /* If it's a list */
-  case list:
-    temp_val= env->head->item;
+  case tcons:
+    temp_val= CAR(env->head);
     protect(temp_val);
 
-    toss(env); if(env->err) return;
-    iterator= (stackitem*)temp_val->content.ptr;
+    env->head= CDR(env->head);
+    iterator= temp_val;
     
-    while(iterator!=NULL) {
-      push_val(env, iterator->item);
+    while(iterator->type != empty) {
+      push_val(env, CAR(iterator));
       
-      if(env->head->item->type==symb
-	 && (((symbol*)(env->head->item->content.ptr))->id[0] == ';')) {
-	toss(env);
-	if(env->err) return;
+     if(CAR(env->head)->type==symb
+	 && CAR(env->head)->content.sym->id[0]==';') {
+	env->head= CDR(env->head);
 	
-	if(iterator->next == NULL){
+	if(CDR(iterator)->type == empty){
 	  goto eval_start;
 	}
 	eval(env);
 	if(env->err) return;
       }
-      iterator= iterator->next;
+      if (CDR(iterator)->type == empty || CDR(iterator)->type == tcons) 
+	iterator= CDR(iterator);
+      else {
+	env->err= 2; /* Improper list */
+	return printerr(env); 
+      }
     }
     unprotect(temp_val);
     return;
 
-  default:
-    return;
-  }
-}
-
-/* Reverse (flip) a list */
-extern void rev(environment *env)
-{
-  stackitem *old_head, *new_head, *item;
-
-  if((env->head)==NULL) {
-    printerr("Too Few Arguments");
-    env->err= 1;
-    return;
-  }
-
-  if(env->head->item->type!=list) {
-    printerr("Bad Argument Type");
-    env->err= 2;
-    return;
-  }
-
-  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;
-  }
-  env->head->item->content.ptr= new_head;
-}
-
-/* Make a list. */
-extern void pack(environment *env)
-{
-  stackitem *iterator, *temp;
-  value *pack;
-
-  iterator= env->head;
-  pack= new_val(env);
-  protect(pack);
-
-  if(iterator==NULL
-     || (iterator->item->type==symb
-     && ((symbol*)(iterator->item->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;
-    
-    /* Extract list */
-    temp= env->head;
-    env->head= iterator->next;
-    iterator->next= NULL;
-
-    pack->type= list;
-    pack->content.ptr= temp;
-    
-    if(env->head!=NULL)
-      toss(env);
-  }
-
-  /* Push list */
-
-  push_val(env, pack);
-  rev(env);
-
-  unprotect(pack);
-}
-
-/* Relocate elements of the list on the stack. */
-extern void expand(environment *env)
-{
-  stackitem *temp, *new_head;
-
-  /* Is top element a list? */
-  if(env->head==NULL) {
-    printerr("Too Few Arguments");
-    env->err= 1;
-    return;
-  }
-  if(env->head->item->type!=list) {
-    printerr("Bad Argument Type");
-    env->err= 2;
-    return;
-  }
-
-  rev(env);
-
-  if(env->err)
-    return;
-
-  /* The first list element is the new stack head */
-  new_head= temp= env->head->item->content.ptr;
-
-  toss(env);
-
-  /* Find the end of the list */
-  while(temp->next!=NULL)
-    temp= temp->next;
-
-  /* Connect the tail of the list with the old stack head */
-  temp->next= env->head;
-  env->head= new_head;		/* ...and voila! */
-
-}
-
-/* Compares two elements by reference. */
-extern void eq(environment *env)
-{
-  void *left, *right;
-  int result;
-
-  if((env->head)==NULL || env->head->next==NULL) {
-    printerr("Too Few Arguments");
-    env->err= 1;
-    return;
-  }
-
-  left= env->head->item->content.ptr;
-  swap(env);
-  right= env->head->item->content.ptr;
-  result= (left==right);
-  
-  toss(env); toss(env);
-  push_int(env, result);
-}
-
-/* Negates the top element on the stack. */
-extern void not(environment *env)
-{
-  int val;
-
-  if((env->head)==NULL) {
-    printerr("Too Few Arguments");
-    env->err= 1;
-    return;
-  }
-
-  if(env->head->item->type!=integer) {
-    printerr("Bad Argument Type");
-    env->err= 2;
-    return;
-  }
-
-  val= env->head->item->content.i;
-  toss(env);
-  push_int(env, !val);
-}
-
-/* Compares the two top elements on the stack and return 0 if they're the
-   same. */
-extern void neq(environment *env)
-{
-  eq(env);
-  not(env);
-}
-
-/* Give a symbol some content. */
-extern void def(environment *env)
-{
-  symbol *sym;
-
-  /* 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;
-    return;
-  }
-
-  if(env->head->item->type!=symb) {
-    printerr("Bad Argument Type");
-    env->err= 2;
+  case empty:
+    env->head= CDR(env->head);
+  case integer:
+  case tfloat:
+  case string:
+  case port:
+  case unknown:
     return;
   }
-
-  /* long names are a pain */
-  sym= env->head->item->content.ptr;
-
-  /* Bind the symbol to the value */
-  sym->val= env->head->next->item;
-
-  toss(env); toss(env);
-} 
-
-/* Quit stack. */
-extern void quit(environment *env)
-{
-  int 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;
-  }
-
-  env->gc_limit= 0;
-  gc_maybe(env);
-
-  if(env->free_string!=NULL)
-    free(env->free_string);
-  
-  muntrace();
-
-  exit(EXIT_SUCCESS);
-}
-
-/* Clear stack */
-extern void clear(environment *env)
-{
-  while(env->head!=NULL)
-    toss(env);
 }
 
-/* List all defined words */
-extern void words(environment *env)
-{
-  symbol *temp;
-  int i;
-  
-  for(i= 0; i<HASHTBLSIZE; i++) {
-    temp= env->symbols[i];
-    while(temp!=NULL) {
-      printf("%s\n", temp->id);
-      temp= temp->next;
-    }
-  }
-}
 
 /* Internal forget function */
 void forget_sym(symbol **hash_entry)
@@ -944,43 +698,15 @@
   free(temp);
 }
 
-/* Forgets a symbol (remove it from the hash table) */
-extern void forget(environment *env)
-{
-  char* sym_id;
-  stackitem *stack_head= env->head;
-
-  if(stack_head==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
-  
-  if(stack_head->item->type!=symb) {
-    printerr("Bad Argument Type");
-    env->err=2;
-    return;
-  }
-
-  sym_id= ((symbol*)(stack_head->item->content.ptr))->id;
-  toss(env);
-
-  return forget_sym(hash(env->symbols, sym_id));
-}
-
-/* Returns the current error number to the stack */
-extern void errn(environment *env)
-{
-  push_int(env, env->err);
-}
 
 int main(int argc, char **argv)
 {
   environment myenv;
-
   int c;			/* getopt option character */
 
+#ifdef __linux__
   mtrace();
+#endif
 
   init_env(&myenv);
 
@@ -994,7 +720,7 @@
 	break;
       case '?':
 	fprintf (stderr,
-		 "Unknown option character `\\x%x'.\n",
+		 "Unknown option character '\\x%x'.\n",
 		 optopt);
 	return EX_USAGE;
       default:
@@ -1010,272 +736,50 @@
     }
   }
 
-  if(myenv.interactive) {
-    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\
-under certain conditions; type `copying;' for details.\n");
-  }
+  if(myenv.interactive)
+    puts(start_message);
 
   while(1) {
     if(myenv.in_string==NULL) {
       if (myenv.interactive) {
 	if(myenv.err) {
 	  printf("(error %d)\n", myenv.err);
+	  myenv.err= 0;
 	}
-	nl();
+	printf("\n");
 	printstack(&myenv);
 	printf("> ");
       }
       myenv.err=0;
     }
-    sx_72656164(&myenv);
-    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]==';') {
-      toss(&myenv); 		/* No error check in main */
+    readstream(&myenv, myenv.inputstream);
+    if (myenv.err) {		/* EOF or other error */
+      myenv.err=0;
+      quit(&myenv);
+    } else if(myenv.head->type!=empty
+	      && CAR(myenv.head)->type==symb
+	      && CAR(myenv.head)->content.sym->id[0] == ';') {
+      if(myenv.head->type != empty)
+	myenv.head= CDR(myenv.head);
       eval(&myenv);
+    } else {
+      gc_maybe(&myenv);
     }
-    gc_maybe(&myenv);
   }
   quit(&myenv);
   return EXIT_FAILURE;
 }
 
-/* "+" */
-extern void sx_2b(environment *env)
-{
-  int a, b;
-  float fa, fb;
-  size_t len;
-  char* new_string;
-  value *a_val, *b_val;
-
-  if((env->head)==NULL || env->head->next==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;
-    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;
-    new_string= malloc(len);
-    strcpy(new_string, b_val->content.ptr);
-    strcat(new_string, a_val->content.ptr);
-    push_cstring(env, new_string);
-    unprotect(a_val); unprotect(b_val);
-    free(new_string);
-    
-    return;
-  }
-  
-  if(env->head->item->type==integer
-     && env->head->next->item->type==integer) {
-    a=env->head->item->content.i;
-    toss(env); if(env->err) return;
-    b=env->head->item->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;
-    toss(env); if(env->err) return;
-    fb= env->head->item->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;
-    toss(env); if(env->err) return;
-    b= env->head->item->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;
-    toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
-    toss(env); if(env->err) return;
-    push_float(env, fb+a);
-
-    return;
-  }
-
-  printerr("Bad Argument Type");
-  env->err=2;
-}
-
-/* "-" */
-extern void sx_2d(environment *env)
-{
-  int a, b;
-  float fa, fb;
-
-  if((env->head)==NULL || env->head->next==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;
-    toss(env); if(env->err) return;
-    b=env->head->item->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;
-    toss(env); if(env->err) return;
-    fb= env->head->item->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;
-    toss(env); if(env->err) return;
-    b= env->head->item->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;
-    toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
-    toss(env); if(env->err) return;
-    push_float(env, fb-a);
-
-    return;
-  }
-
-  printerr("Bad Argument Type");
-  env->err=2;
-}
-
-/* ">" */
-extern void sx_3e(environment *env)
-{
-  int a, b;
-  float fa, fb;
-
-  if((env->head)==NULL || env->head->next==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;
-    toss(env); if(env->err) return;
-    b=env->head->item->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;
-    toss(env); if(env->err) return;
-    fb= env->head->item->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;
-    toss(env); if(env->err) return;
-    b= env->head->item->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;
-    toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
-    toss(env); if(env->err) return;
-    push_int(env, fb>a);
-
-    return;
-  }
-
-  printerr("Bad Argument Type");
-  env->err=2;
-}
-
-/* "<" */
-extern void sx_3c(environment *env) 
-{
-  swap(env); if(env->err) return;
-  sx_3e(env);
-}
-
-/* "<=" */
-extern void sx_3c3d(environment *env)
-{
-  sx_3e(env); if(env->err) return;
-  not(env);
-}
-
-/* ">=" */
-extern void sx_3e3d(environment *env)
-{
-  sx_3c(env); if(env->err) return;
-  not(env);
-}
 
 /* Return copy of a value */
 value *copy_val(environment *env, value *old_value)
 {
-  stackitem *old_item, *new_item, *prev_item;
   value *new_value;
 
-  protect(old_value);
+  if(old_value==NULL)
+    return NULL;
+
   new_value= new_val(env);
-  protect(new_value);
   new_value->type= old_value->type;
 
   switch(old_value->type){
@@ -1283,330 +787,108 @@
   case integer:
   case func:
   case symb:
+  case empty:
+  case unknown:
+  case port:
     new_value->content= old_value->content;
     break;
   case string:
-    (char *)(new_value->content.ptr)= 
-      strdup((char *)(old_value->content.ptr));
+    new_value->content.string= strdup(old_value->content.string);
     break;
-  case list:
-    new_value->content.ptr= NULL;
+  case tcons:
 
-    prev_item= NULL;
-    old_item= (stackitem*)(old_value->content.ptr);
+    new_value->content.c= malloc(sizeof(pair));
+    assert(new_value->content.c!=NULL);
+    env->gc_count += sizeof(pair);
 
-    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;
-      if(prev_item != NULL)	/* If this wasn't the first item */
-	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;
-    }	  
+    CAR(new_value)= copy_val(env, CAR(old_value)); /* recurse */
+    CDR(new_value)= copy_val(env, CDR(old_value)); /* recurse */
     break;
   }
 
-  unprotect(old_value); unprotect(new_value);
-
   return new_value;
 }
 
-/* "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, env->head->item));
-}
-
-/* "if", If-Then */
-extern void sx_6966(environment *env)
-{
-  int truth;
-
-  if((env->head)==NULL || env->head->next==NULL) {
-    printerr("Too Few Arguments");
-    env->err= 1;
-    return;
-  }
-
-  if(env->head->next->item->type != integer) {
-    printerr("Bad Argument Type");
-    env->err=2;
-    return;
-  }
-  
-  swap(env);
-  if(env->err) return;
-  
-  truth=env->head->item->content.i;
-
-  toss(env);
-  if(env->err) return;
-
-  if(truth)
-    eval(env);
-  else
-    toss(env);
-}
-
-/* If-Then-Else */
-extern void ifelse(environment *env)
-{
-  int truth;
-
-  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->next->item->type != integer) {
-    printerr("Bad Argument Type");
-    env->err=2;
-    return;
-  }
-  
-  rot(env);
-  if(env->err) return;
-  
-  truth=env->head->item->content.i;
-
-  toss(env);
-  if(env->err) return;
-
-  if(!truth)
-    swap(env);
-  if(env->err) return;
-
-  toss(env);
-  if(env->err) return;
-
-  eval(env);
-}
-
-/* "while" */
-extern void sx_7768696c65(environment *env)
-{
-  int truth;
-  value *loop, *test;
-
-  if((env->head)==NULL || env->head->next==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
-
-  loop= env->head->item;
-  protect(loop);
-  toss(env); if(env->err) return;
-
-  test= env->head->item;
-  protect(test);
-  toss(env); if(env->err) return;
-
-  do {
-    push_val(env, test);
-    eval(env);
-    
-    if(env->head->item->type != integer) {
-      printerr("Bad Argument Type");
-      env->err= 2;
-      return;
-    }
-    
-    truth= env->head->item->content.i;
-    toss(env); if(env->err) return;
-    
-    if(truth) {
-      push_val(env, loop);
-      eval(env);
-    } else {
-      toss(env);
-    }
-  
-  } while(truth);
-
-  unprotect(loop); unprotect(test);
-}
-
 
-/* "for"; for-loop */
-extern void sx_666f72(environment *env)
+/* read a line from a stream; used by readline */
+void readlinestream(environment *env, FILE *stream)
 {
-  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;
-  }
+  char in_string[101];
 
-  loop= env->head->item;
-  protect(loop);
-  toss(env); if(env->err) return;
-
-  foo2= env->head->item->content.i;
-  toss(env); if(env->err) return;
-
-  foo1= env->head->item->content.i;
-  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++;
+  if(fgets(in_string, 100, stream)==NULL) {
+    push_cstring(env, "");
+    if (! feof(stream)){
+      env->err= 5;
+      return printerr(env);
     }
   } else {
-    while(foo1>=foo2) {
-      push_int(env, foo1);
-      push_val(env, loop);
-      eval(env); if(env->err) return;
-      foo1--;
-    }
+    push_cstring(env, in_string);
   }
-  unprotect(loop);
 }
 
-/* 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;
-    return;
-  }
-
-  if(env->head->next->item->type != list) {
-    printerr("Bad Argument Type");
-    env->err= 2;
-    return;
-  }
 
-  loop= env->head->item;
-  protect(loop);
-  toss(env); if(env->err) return;
+/* Reverse (flip) a list */
+extern void rev(environment *env)
+{
+  value *old_head, *new_head, *item;
 
-  foo= env->head->item;
-  protect(foo);
-  toss(env); if(env->err) return;
+  if(CAR(env->head)->type==empty)
+    return;			/* Don't reverse an empty list */
 
-  iterator= foo->content.ptr;
+  if(check_args(env, 1, tcons))
+    return printerr(env);
 
-  while(iterator!=NULL) {
-    push_val(env, iterator->item);
-    push_val(env, loop);
-    eval(env); if(env->err) return;
-    iterator= iterator->next;
+  old_head= CAR(env->head);
+  new_head= new_val(env);
+  while(old_head->type != empty) {
+    item= old_head;
+    old_head= CDR(old_head);
+    CDR(item)= new_head;
+    new_head= item;
   }
-  unprotect(loop); unprotect(foo);
+  CAR(env->head)= new_head;
 }
 
-/* "to" */
-extern void to(environment *env)
-{
-  int ending, start, i;
-  stackitem *iterator, *temp;
-  value *pack;
-
-  if((env->head)==NULL || env->head->next==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
 
-  if(env->head->item->type!=integer 
-     || env->head->next->item->type!=integer) {
-    printerr("Bad Argument Type");
-    env->err=2;
-    return;
-  }
+/* Make a list. */
+extern void pack(environment *env)
+{
+  value *iterator, *temp, *ending;
 
-  ending= env->head->item->content.i;
-  toss(env); if(env->err) return;
-  start= env->head->item->content.i;
-  toss(env); if(env->err) return;
-
-  push_sym(env, "[");
-
-  if(ending>=start) {
-    for(i= ending; i>=start; i--)
-      push_int(env, i);
-  } else {
-    for(i= ending; i<=start; i++)
-      push_int(env, i);
-  }
+  ending=new_val(env);
 
   iterator= env->head;
-  pack= new_val(env);
-  protect(pack);
-
-  if(iterator==NULL
-     || (iterator->item->type==symb
-     && ((symbol*)(iterator->item->content.ptr))->id[0]=='[')) {
-    temp= NULL;
-    toss(env);
+  if(iterator->type == empty
+     || (CAR(iterator)->type==symb
+     && CAR(iterator)->content.sym->id[0]=='[')) {
+    temp= ending;
+    if(env->head->type != empty)
+      env->head= CDR(env->head);
   } 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(CDR(iterator)->type != empty
+	  && (CAR(CDR(iterator))->type!=symb
+	   || CAR(CDR(iterator))->content.sym->id[0]!='['))
+      iterator= CDR(iterator);
     
     /* Extract list */
     temp= env->head;
-    env->head= iterator->next;
-    iterator->next= NULL;
+    env->head= CDR(iterator);
+    CDR(iterator)= ending;
 
-    pack->type= list;
-    pack->content.ptr= temp;
-    
-    if(env->head!=NULL)
-      toss(env);
+    if(env->head->type != empty)
+      env->head= CDR(env->head);
   }
 
   /* Push list */
 
-  push_val(env, pack);
-
-  unprotect(pack);
+  push_val(env, temp);
+  rev(env);
 }
 
-/* Read a string */
-extern void readline(environment *env)
-{
-  char in_string[101];
-
-  if(fgets(in_string, 100, env->inputstream)==NULL)
-    push_cstring(env, "");
-  else
-    push_cstring(env, in_string);
-}
 
-/* "read"; Read a value and place on stack */
-extern void sx_72656164(environment *env)
+/* read from a stream; used by "read" and "readport" */
+void readstream(environment *env, FILE *stream)
 {
   const char symbform[]= "%[a-zA-Z0-9!$%*+./:<=>?@^_~-]%n";
   const char strform[]= "\"%[^\"]\"%n";
@@ -1621,28 +903,31 @@
   int count= -1;
   float ftemp;
   static int depth= 0;
-  char *match, *ctemp;
+  char *match;
   size_t inlength;
 
   if(env->in_string==NULL) {
     if(depth > 0 && env->interactive) {
       printf("]> ");
     }
-    readline(env); if(env->err) return;
+    readlinestream(env, env->inputstream);
+    if(env->err) return;
 
-    if(((char *)(env->head->item->content.ptr))[0]=='\0'){
+    if((CAR(env->head)->content.string)[0]=='\0'){
       env->err= 4;		/* "" means EOF */
       return;
     }
     
-    env->in_string= malloc(strlen(env->head->item->content.ptr)+1);
+    env->in_string= malloc(strlen(CAR(env->head)->content.string)+1);
+    assert(env->in_string != NULL);
     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;
+    strcpy(env->in_string, CAR(env->head)->content.string);
+    env->head= CDR(env->head);
   }
   
   inlength= strlen(env->in_string)+1;
   match= malloc(inlength);
+  assert(match != NULL);
 
   if(sscanf(env->in_string, blankform, &readlength) != EOF
      && readlength != -1) {
@@ -1655,6 +940,9 @@
     } else {
       push_float(env, ftemp);
     }
+  } else if(sscanf(env->in_string, "\"\"%n", &readlength) != EOF
+	    && readlength != -1) {
+    push_cstring(env, "");
   } else if(sscanf(env->in_string, strform, match, &readlength) != EOF
 	    && readlength != -1) {
     push_cstring(env, match);
@@ -1683,528 +971,39 @@
   free(match);
 
   if(depth)
-    return sx_72656164(env);
-}
-
-extern void beep(environment *env)
-{
-  int freq, dur, period, ticks;
-
-  if((env->head)==NULL || env->head->next==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
-
-  if(env->head->item->type!=integer
-     || env->head->next->item->type!=integer) {
-    printerr("Bad Argument Type");
-    env->err=2;
-    return;
-  }
-
-  dur=env->head->item->content.i;
-  toss(env);
-  freq=env->head->item->content.i;
-  toss(env);
-
-  period=1193180/freq;		/* convert freq from Hz to period
-                                   length */
-  ticks=dur*.001193180;		/* convert duration from µseconds to
-				   timer ticks */
-
-/*    ticks=dur/1000; */
-
-  /*  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;
-    return;
-  default:
-    abort();
-  }
+    return readstream(env, env->inputstream);
 }
 
-/* "wait" */
-extern void sx_77616974(environment *env)
-{
-  int dur;
-
-  if((env->head)==NULL) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
-
-  if(env->head->item->type!=integer) {
-    printerr("Bad Argument Type");
-    env->err=2;
-    return;
-  }
-
-  dur=env->head->item->content.i;
-  toss(env);
 
-  usleep(dur);
-}
-
-extern void copying(environment *env)
+int check_args(environment *env, int num_args, ...)
 {
-  printf("GNU GENERAL PUBLIC LICENSE\n\
-		       Version 2, June 1991\n\
-\n\
- Copyright (C) 1989, 1991 Free Software Foundation, Inc.\n\
-     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA\n\
- Everyone is permitted to copy and distribute verbatim copies\n\
- of this license document, but changing it is not allowed.\n\
-\n\
-			    Preamble\n\
-\n\
-  The licenses for most software are designed to take away your\n\
-freedom to share and change it.  By contrast, the GNU General Public\n\
-License is intended to guarantee your freedom to share and change free\n\
-software--to make sure the software is free for all its users.  This\n\
-General Public License applies to most of the Free Software\n\
-Foundation's software and to any other program whose authors commit to\n\
-using it.  (Some other Free Software Foundation software is covered by\n\
-the GNU Library General Public License instead.)  You can apply it to\n\
-your programs, too.\n\
-\n\
-  When we speak of free software, we are referring to freedom, not\n\
-price.  Our General Public Licenses are designed to make sure that you\n\
-have the freedom to distribute copies of free software (and charge for\n\
-this service if you wish), that you receive source code or can get it\n\
-if you want it, that you can change the software or use pieces of it\n\
-in new free programs; and that you know you can do these things.\n\
-\n\
-  To protect your rights, we need to make restrictions that forbid\n\
-anyone to deny you these rights or to ask you to surrender the rights.\n\
-These restrictions translate to certain responsibilities for you if you\n\
-distribute copies of the software, or if you modify it.\n\
-\n\
-  For example, if you distribute copies of such a program, whether\n\
-gratis or for a fee, you must give the recipients all the rights that\n\
-you have.  You must make sure that they, too, receive or can get the\n\
-source code.  And you must show them these terms so they know their\n\
-rights.\n\
-\n\
-  We protect your rights with two steps: (1) copyright the software, and\n\
-(2) offer you this license which gives you legal permission to copy,\n\
-distribute and/or modify the software.\n\
-\n\
-  Also, for each author's protection and ours, we want to make certain\n\
-that everyone understands that there is no warranty for this free\n\
-software.  If the software is modified by someone else and passed on, we\n\
-want its recipients to know that what they have is not the original, so\n\
-that any problems introduced by others will not reflect on the original\n\
-authors' reputations.\n\
-\n\
-  Finally, any free program is threatened constantly by software\n\
-patents.  We wish to avoid the danger that redistributors of a free\n\
-program will individually obtain patent licenses, in effect making the\n\
-program proprietary.  To prevent this, we have made it clear that any\n\
-patent must be licensed for everyone's free use or not licensed at all.\n\
-\n\
-  The precise terms and conditions for copying, distribution and\n\
-modification follow.\n\
-\n\
-		    GNU GENERAL PUBLIC LICENSE\n\
-   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION\n\
-\n\
-  0. This License applies to any program or other work which contains\n\
-a notice placed by the copyright holder saying it may be distributed\n\
-under the terms of this General Public License.  The \"Program\", below,\n\
-refers to any such program or work, and a \"work based on the Program\"\n\
-means either the Program or any derivative work under copyright law:\n\
-that is to say, a work containing the Program or a portion of it,\n\
-either verbatim or with modifications and/or translated into another\n\
-language.  (Hereinafter, translation is included without limitation in\n\
-the term \"modification\".)  Each licensee is addressed as \"you\".\n\
-\n\
-Activities other than copying, distribution and modification are not\n\
-covered by this License; they are outside its scope.  The act of\n\
-running the Program is not restricted, and the output from the Program\n\
-is covered only if its contents constitute a work based on the\n\
-Program (independent of having been made by running the Program).\n\
-Whether that is true depends on what the Program does.\n\
-\n\
-  1. You may copy and distribute verbatim copies of the Program's\n\
-source code as you receive it, in any medium, provided that you\n\
-conspicuously and appropriately publish on each copy an appropriate\n\
-copyright notice and disclaimer of warranty; keep intact all the\n\
-notices that refer to this License and to the absence of any warranty;\n\
-and give any other recipients of the Program a copy of this License\n\
-along with the Program.\n\
-\n\
-You may charge a fee for the physical act of transferring a copy, and\n\
-you may at your option offer warranty protection in exchange for a fee.\n\
-\n\
-  2. You may modify your copy or copies of the Program or any portion\n\
-of it, thus forming a work based on the Program, and copy and\n\
-distribute such modifications or work under the terms of Section 1\n\
-above, provided that you also meet all of these conditions:\n\
-\n\
-    a) You must cause the modified files to carry prominent notices\n\
-    stating that you changed the files and the date of any change.\n\
-\n\
-    b) You must cause any work that you distribute or publish, that in\n\
-    whole or in part contains or is derived from the Program or any\n\
-    part thereof, to be licensed as a whole at no charge to all third\n\
-    parties under the terms of this License.\n\
-\n\
-    c) If the modified program normally reads commands interactively\n\
-    when run, you must cause it, when started running for such\n\
-    interactive use in the most ordinary way, to print or display an\n\
-    announcement including an appropriate copyright notice and a\n\
-    notice that there is no warranty (or else, saying that you provide\n\
-    a warranty) and that users may redistribute the program under\n\
-    these conditions, and telling the user how to view a copy of this\n\
-    License.  (Exception: if the Program itself is interactive but\n\
-    does not normally print such an announcement, your work based on\n\
-    the Program is not required to print an announcement.)\n\
-\n\
-These requirements apply to the modified work as a whole.  If\n\
-identifiable sections of that work are not derived from the Program,\n\
-and can be reasonably considered independent and separate works in\n\
-themselves, then this License, and its terms, do not apply to those\n\
-sections when you distribute them as separate works.  But when you\n\
-distribute the same sections as part of a whole which is a work based\n\
-on the Program, the distribution of the whole must be on the terms of\n\
-this License, whose permissions for other licensees extend to the\n\
-entire whole, and thus to each and every part regardless of who wrote it.\n\
-\n\
-Thus, it is not the intent of this section to claim rights or contest\n\
-your rights to work written entirely by you; rather, the intent is to\n\
-exercise the right to control the distribution of derivative or\n\
-collective works based on the Program.\n\
-\n\
-In addition, mere aggregation of another work not based on the Program\n\
-with the Program (or with a work based on the Program) on a volume of\n\
-a storage or distribution medium does not bring the other work under\n\
-the scope of this License.\n\
-\n\
-  3. You may copy and distribute the Program (or a work based on it,\n\
-under Section 2) in object code or executable form under the terms of\n\
-Sections 1 and 2 above provided that you also do one of the following:\n\
-\n\
-    a) Accompany it with the complete corresponding machine-readable\n\
-    source code, which must be distributed under the terms of Sections\n\
-    1 and 2 above on a medium customarily used for software interchange; or,\n\
-\n\
-    b) Accompany it with a written offer, valid for at least three\n\
-    years, to give any third party, for a charge no more than your\n\
-    cost of physically performing source distribution, a complete\n\
-    machine-readable copy of the corresponding source code, to be\n\
-    distributed under the terms of Sections 1 and 2 above on a medium\n\
-    customarily used for software interchange; or,\n\
-\n\
-    c) Accompany it with the information you received as to the offer\n\
-    to distribute corresponding source code.  (This alternative is\n\
-    allowed only for noncommercial distribution and only if you\n\
-    received the program in object code or executable form with such\n\
-    an offer, in accord with Subsection b above.)\n\
-\n\
-The source code for a work means the preferred form of the work for\n\
-making modifications to it.  For an executable work, complete source\n\
-code means all the source code for all modules it contains, plus any\n\
-associated interface definition files, plus the scripts used to\n\
-control compilation and installation of the executable.  However, as a\n\
-special exception, the source code distributed need not include\n\
-anything that is normally distributed (in either source or binary\n\
-form) with the major components (compiler, kernel, and so on) of the\n\
-operating system on which the executable runs, unless that component\n\
-itself accompanies the executable.\n\
-\n\
-If distribution of executable or object code is made by offering\n\
-access to copy from a designated place, then offering equivalent\n\
-access to copy the source code from the same place counts as\n\
-distribution of the source code, even though third parties are not\n\
-compelled to copy the source along with the object code.\n\
-\n\
-  4. You may not copy, modify, sublicense, or distribute the Program\n\
-except as expressly provided under this License.  Any attempt\n\
-otherwise to copy, modify, sublicense or distribute the Program is\n\
-void, and will automatically terminate your rights under this License.\n\
-However, parties who have received copies, or rights, from you under\n\
-this License will not have their licenses terminated so long as such\n\
-parties remain in full compliance.\n\
-\n\
-  5. You are not required to accept this License, since you have not\n\
-signed it.  However, nothing else grants you permission to modify or\n\
-distribute the Program or its derivative works.  These actions are\n\
-prohibited by law if you do not accept this License.  Therefore, by\n\
-modifying or distributing the Program (or any work based on the\n\
-Program), you indicate your acceptance of this License to do so, and\n\
-all its terms and conditions for copying, distributing or modifying\n\
-the Program or works based on it.\n\
-\n\
-  6. Each time you redistribute the Program (or any work based on the\n\
-Program), the recipient automatically receives a license from the\n\
-original licensor to copy, distribute or modify the Program subject to\n\
-these terms and conditions.  You may not impose any further\n\
-restrictions on the recipients' exercise of the rights granted herein.\n\
-You are not responsible for enforcing compliance by third parties to\n\
-this License.\n\
-\n\
-  7. If, as a consequence of a court judgment or allegation of patent\n\
-infringement or for any other reason (not limited to patent issues),\n\
-conditions are imposed on you (whether by court order, agreement or\n\
-otherwise) that contradict the conditions of this License, they do not\n\
-excuse you from the conditions of this License.  If you cannot\n\
-distribute so as to satisfy simultaneously your obligations under this\n\
-License and any other pertinent obligations, then as a consequence you\n\
-may not distribute the Program at all.  For example, if a patent\n\
-license would not permit royalty-free redistribution of the Program by\n\
-all those who receive copies directly or indirectly through you, then\n\
-the only way you could satisfy both it and this License would be to\n\
-refrain entirely from distribution of the Program.\n\
-\n\
-If any portion of this section is held invalid or unenforceable under\n\
-any particular circumstance, the balance of the section is intended to\n\
-apply and the section as a whole is intended to apply in other\n\
-circumstances.\n\
-\n\
-It is not the purpose of this section to induce you to infringe any\n\
-patents or other property right claims or to contest validity of any\n\
-such claims; this section has the sole purpose of protecting the\n\
-integrity of the free software distribution system, which is\n\
-implemented by public license practices.  Many people have made\n\
-generous contributions to the wide range of software distributed\n\
-through that system in reliance on consistent application of that\n\
-system; it is up to the author/donor to decide if he or she is willing\n\
-to distribute software through any other system and a licensee cannot\n\
-impose that choice.\n\
-\n\
-This section is intended to make thoroughly clear what is believed to\n\
-be a consequence of the rest of this License.\n\
-\n\
-  8. If the distribution and/or use of the Program is restricted in\n\
-certain countries either by patents or by copyrighted interfaces, the\n\
-original copyright holder who places the Program under this License\n\
-may add an explicit geographical distribution limitation excluding\n\
-those countries, so that distribution is permitted only in or among\n\
-countries not thus excluded.  In such case, this License incorporates\n\
-the limitation as if written in the body of this License.\n\
-\n\
-  9. The Free Software Foundation may publish revised and/or new versions\n\
-of the General Public License from time to time.  Such new versions will\n\
-be similar in spirit to the present version, but may differ in detail to\n\
-address new problems or concerns.\n\
-\n\
-Each version is given a distinguishing version number.  If the Program\n\
-specifies a version number of this License which applies to it and \"any\n\
-later version\", you have the option of following the terms and conditions\n\
-either of that version or of any later version published by the Free\n\
-Software Foundation.  If the Program does not specify a version number of\n\
-this License, you may choose any version ever published by the Free Software\n\
-Foundation.\n\
-\n\
-  10. If you wish to incorporate parts of the Program into other free\n\
-programs whose distribution conditions are different, write to the author\n\
-to ask for permission.  For software which is copyrighted by the Free\n\
-Software Foundation, write to the Free Software Foundation; we sometimes\n\
-make exceptions for this.  Our decision will be guided by the two goals\n\
-of preserving the free status of all derivatives of our free software and\n\
-of promoting the sharing and reuse of software generally.\n");
-}
-
-extern void warranty(environment *env)
-{
-  printf("			    NO WARRANTY\n\
-\n\
-  11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY\n\
-FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN\n\
-OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES\n\
-PROVIDE THE PROGRAM \"AS IS\" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED\n\
-OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF\n\
-MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS\n\
-TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE\n\
-PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,\n\
-REPAIR OR CORRECTION.\n\
-\n\
-  12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING\n\
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR\n\
-REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,\n\
-INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING\n\
-OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED\n\
-TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY\n\
-YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER\n\
-PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE\n\
-POSSIBILITY OF SUCH DAMAGES.\n");
-}
-
-/* "*" */
-extern void sx_2a(environment *env)
-{
-  int a, b;
-  float fa, fb;
-
-  if((env->head)==NULL || env->head->next==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;
-    toss(env); if(env->err) return;
-    b=env->head->item->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;
-    toss(env); if(env->err) return;
-    fb= env->head->item->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;
-    toss(env); if(env->err) return;
-    b= env->head->item->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;
-    toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
-    toss(env); if(env->err) return;
-    push_float(env, fb*a);
-
-    return;
-  }
-
-  printerr("Bad Argument Type");
-  env->err=2;
-}
-
-/* "/" */
-extern void sx_2f(environment *env)
-{
-  int a, b;
-  float fa, fb;
-
-  if((env->head)==NULL || env->head->next==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;
-    toss(env); if(env->err) return;
-    b=env->head->item->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;
-    toss(env); if(env->err) return;
-    fb= env->head->item->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;
-    toss(env); if(env->err) return;
-    b= env->head->item->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;
-    toss(env); if(env->err) return;
-    fb= env->head->item->content.f;
-    toss(env); if(env->err) return;
-    push_float(env, fb/a);
-
-    return;
-  }
-
-  printerr("Bad Argument Type");
-  env->err=2;
-}
+  va_list ap;
+  enum type_enum mytype;
+  int i;
 
-/* "mod" */
-extern void mod(environment *env)
-{
-  int a, b;
+  value *iter= env->head;
+  int errval= 0;
 
-  if((env->head)==NULL || env->head->next==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;
-    toss(env); if(env->err) return;
-    b= env->head->item->content.i;
-    toss(env); if(env->err) return;
-    push_int(env, b%a);
+  va_start(ap, num_args);
+  for(i=1; i<=num_args; i++) {
+    mytype= va_arg(ap, enum type_enum);
+    //    fprintf(stderr, "%s\n", env->errsymb); 
 
-    return;
-  }
+    if(iter->type==empty || iter==NULL) {
+      errval= 1;
+      break;
+    }
 
-  printerr("Bad Argument Type");
-  env->err=2;
-}
+    if(mytype!=unknown && CAR(iter)->type!=mytype) {
+      errval= 2;
+      break;
+    }
 
-/* "div" */
-extern void sx_646976(environment *env)
-{
-  int a, b;
-  
-  if((env->head)==NULL || env->head->next==NULL) {
-    printerr("Too Few Arguments");
-    env->err= 1;
-    return;
+    iter= CDR(iter);
   }
 
-  if(env->head->item->type==integer
-     && env->head->next->item->type==integer) {
-    a= env->head->item->content.i;
-    toss(env); if(env->err) return;
-    b= env->head->item->content.i;
-    toss(env); if(env->err) return;
-    push_int(env, (int)b/a);
-
-    return;
-  }
+  va_end(ap);
 
-  printerr("Bad Argument Type");
-  env->err= 2;
+  env->err= errval;
+  return errval;
 }