X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=scheme-library.scm;h=1a68a10d43a56e08ad417787677fe2629f3809d7;hb=fa6316fc696ddda325b2e2a8af83f4024ddf32bd;hp=dc345cf7e7d688ea11cd1a0b043d092f74814d89;hpb=9b75e5d50017b95ee8d10ade294c6676a1a60af4;p=scheme.forth.jl.git

diff --git a/scheme-library.scm b/scheme-library.scm
index dc345cf..1a68a10 100644
--- a/scheme-library.scm
+++ b/scheme-library.scm
@@ -28,11 +28,26 @@
     (append (reverse (cdr l)) (list (car l)))))
 
 ;; LIBRARY FORMS
-(define-macro (let value . body )
-              (list (list 'lambda (list (car value)) body)) (cdr value))
+
+(define-macro (while condition . body)
+              `(begin
+                 (define (loop)
+                   (if ,condition
+                     (begin ,@body (loop))))
+                 (loop)))
 
 ;; TESTING
 
+(define-macro (backwards . body)
+              (cons 'begin (reverse body)))
+
+; Test for the while macro.
+(define (count)
+  (define counter 10)
+  (while (> counter 0)
+         (display counter) (newline)
+         (set! counter (- counter 1))))
+
 ; Basic iterative summation.  Run this on large numbers to
 ; test garbage collection and tail-call optimization.
 (define (sum n)