stdlib changes

stdlib/stdlib.lsp

@@ -1,19 +1,11 @@
 ; not a bool
 (defun not (x) (if x 0 1))
 
-; negate a number
-(defun neg (n) (- 0 n))
-
-; is a number positive?
 (defun is-pos? (n) (> n 0))
-
-; is a number negative?
 (defun is-neg? (n) (< n 0))
 
-; decrement a number
+(defun neg (n) (- 0 n))
 (defun dec (n) (- n 1))
-
-; increment a number
 (defun inc (n) (+ n 1))
 
 
@@ -34,6 +26,20 @@
 (defun string-downcase (str) 
     (string-case str "lower"))
 
+
+(defun string-join (lst sep)
+(do
+	(define rslt "")
+	(define i 0)
+	(for e lst
+        (if (= i 0)
+			(define rslt (display e))
+			(define rslt (+ rslt (display sep) (display e))))
+		(define i (inc i)))
+	rslt
+	))
+
+
 ; pause for interval of seconds
 (defun sleep (time) 
   (system-cmd (+ "sleep " (string time))))
@@ -46,7 +52,7 @@
 (defun third (l) (index l 2))
 (defun fourth (l) (index l 3))
 (defun fifth (l) (index l 4))
-(defun nth (i l) (index l (- i 1))
+(defun nth (i l) (index l (- i 1)))
 
 ; return 1 when list contains item otherwise 0
 (defun member (lst itm) 
@@ -81,6 +87,8 @@
 (defun make-list (size)
     (make-list-of size nil))
 
+(defun empty-list? (lst) (and (= (type lst) "list") (= (len lst) 0)))
+
 (defun uniq (lst)
     (do
         (define rslt '())    
@@ -106,7 +114,6 @@
                         (define rslt (push rslt ee))))
                 (define rslt (push rslt e))
             ))
-
         rslt
     ))