--- stack/stack.c	2003/08/08 14:20:49	1.132
+++ stack/stack.c	2003/08/13 11:58:00	1.135
@@ -23,7 +23,7 @@
 
 #include "stack.h"
 
-const char* start_message= "Stack version $Revision: 1.132 $\n\
+const char* start_message= "Stack version $Revision: 1.135 $\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\
@@ -50,9 +50,28 @@
 }
 
 
-void printerr(const char* in_string)
+void printerr(environment *env)
 {
-  fprintf(stderr, "Err: %s\n", in_string);
+  char *in_string;
+
+  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;
+  default:
+    in_string= "Unknown error";
+    break;
+  }
+
+  fprintf(stderr, "\"%s\":\nErr: %s\n", env->errsymb, in_string);
 }
 
 
@@ -167,6 +186,7 @@
 	break;
       case port:
       case empty:
+      case unknown:
       case integer:
       case tfloat:
       case func:
@@ -364,9 +384,7 @@
   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;
@@ -414,7 +432,6 @@
   }
 
   push_val(env, new_value);
-  unprotect(new_value); unprotect(new_fvalue);
 }
 
 
@@ -433,6 +450,13 @@
       return;
     }
     break;
+  case unknown:
+    if(fprintf(stream, "UNKNOWN") < 0){
+      perror("print_val");
+      env->err= 5;
+      return;
+    }
+    break;
   case integer:
     if(fprintf(stream, "%d", val->content.i) < 0){
       perror("print_val");
@@ -580,13 +604,10 @@
 extern void swap(environment *env)
 {
   value *temp= env->head;
-  
-  if(env->head->type == empty || CDR(env->head)->type == empty) {
-    printerr("Too Few Arguments");
-    env->err=1;
-    return;
-  }
 
+  if(check_args(env, unknown, unknown, empty))
+    return printerr(env);
+  
   env->head= CDR(env->head);
   CDR(temp)= CDR(env->head);
   CDR(env->head)= temp;
@@ -598,24 +619,15 @@
 {
   value *val;
 
-  if(env->head->type==empty) {
-    printerr("Too Few Arguments");
-    env->err= 1;
-    return;
-  }
-
-  if(CAR(env->head)->type!=symb) {
-    printerr("Bad Argument Type");
-    env->err= 2;
-    return;
-  }
+  if(check_args(env, symb, empty))
+    return printerr(env);
 
   val= CAR(env->head)->content.sym->val;
   if(val == NULL){
-    printerr("Unbound Variable");
     env->err= 3;
-    return;
+    return printerr(env);
   }
+
   push_val(env, val);		/* Return the symbol's bound value */
   swap(env);
   if(env->err) return;
@@ -636,15 +648,13 @@
 
   gc_maybe(env);
 
-  if(env->head->type==empty) {
-    printerr("Too Few Arguments");
-    env->err= 1;
-    return;
-  }
+  if(check_args(env, unknown, empty))
+    return printerr(env);
 
   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(CAR(env->head)->type!=symb){ /* don't recurse symbols */
@@ -656,7 +666,7 @@
   case func:
     in_func= CAR(env->head)->content.func;
     env->head= CDR(env->head);
-    return in_func(env);
+    return in_func((void*)env);
 
     /* If it's a list */
   case tcons:
@@ -682,9 +692,8 @@
       if (CDR(iterator)->type == empty || CDR(iterator)->type == tcons) 
 	iterator= CDR(iterator);
       else {
-	printerr("Bad Argument Type"); /* Improper list */
-	env->err= 2;
-	return;
+	env->err= 2; /* Improper list */
+	return printerr(env); 
       }
     }
     unprotect(temp_val);
@@ -696,6 +705,7 @@
   case tfloat:
   case string:
   case port:
+  case unknown:
     return;
   }
 }
@@ -752,7 +762,7 @@
   }
 
   if(myenv.interactive)
-    printf(start_message);
+    puts(start_message);
 
   while(1) {
     if(myenv.in_string==NULL) {
@@ -803,6 +813,7 @@
   case func:
   case symb:
   case empty:
+  case unknown:
   case port:
     new_value->content= old_value->content;
     break;
@@ -846,20 +857,11 @@
 {
   value *old_head, *new_head, *item;
 
-  if(env->head->type==empty) {
-    printerr("Too Few Arguments");
-    env->err= 1;
-    return;
-  }
-
   if(CAR(env->head)->type==empty)
     return;			/* Don't reverse an empty list */
 
-  if(CAR(env->head)->type!=tcons) {
-    printerr("Bad Argument Type");
-    env->err= 2;
-    return;
-  }
+  if(check_args(env, tcons, empty))
+    return printerr(env);
 
   old_head= CAR(env->head);
   new_head= new_val(env);
@@ -996,3 +998,44 @@
   if(depth)
     return readstream(env, env->inputstream);
 }
+
+
+int check_args(environment *env, ...)
+{
+  va_list ap;
+  enum type_enum mytype;
+
+  value *iter= env->head;
+  int errval= 0;
+
+  va_start(ap, env);
+  while(1) {
+    mytype= va_arg(ap, enum type_enum);
+    //    fprintf(stderr, "%s\n", env->errsymb); 
+
+    if(mytype==empty)
+      break;
+    
+    if(iter->type==empty || iter==NULL) {
+      errval= 1;
+      break;
+    }
+
+    if(mytype==unknown) {
+      iter=CDR(iter);
+      continue;
+    }
+
+    if(CAR(iter)->type!=mytype) {
+      errval= 2;
+      break;
+    }
+
+    iter= CDR(iter);
+  }
+
+  va_end(ap);
+
+  env->err= errval;
+  return errval;
+}