2013-04-21: added a helper function for nth. Problem with wisp: tail calls are

added a helper function for nth. Problem with wisp: tail calls are *very* convenient, so I really want to use them.

diff --git a/wisp.w b/wisp.w
--- a/wisp.w
+++ b/wisp.w
@@ -1,4 +1,4 @@
-#!/usr/bin/env guilewisp 
+#!/usr/bin/env guile
 ; !#
 
 ; Test
@@ -6,14 +6,14 @@
 display "Hello World!"
 newline
 
+define : nth idx form
+    list-ref form idx
+
 let 
     :
         origfile 
-            open-file 
-                list-ref 
-                    command-line
-                    . 1
-                . "r"
+            open-file : nth 1 : command-line
+                . "r" ; mode
     
     let : : nextchar : read-char origfile
         while : not : eof-object? nextchar