shithub: femtolisp

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adding (do ) form

--- a/femtolisp/system.lsp

+++ b/femtolisp/system.lsp

@@ -424,6 +424,25 @@

 			    (cdr clause)))

 		    clauses)))))

+(define-macro (do vars test-spec . commands)

+  (let ((loop (gensym))

+	(test-expr (car test-spec))

+	(vars  (map car  vars))

+	(inits (map cadr vars))

+	(steps (map (lambda (x)

+		      (if (pair? (cddr x))

+			  (caddr x)

+			  (car x)))

+		    vars)))

+    `(letrec ((,loop (lambda ,vars

+		       (if ,test-expr

+			   (begin

+			     ,@(cdr test-spec))

+			   (begin

+			     ,@commands

+			     (,loop ,@steps))))))

+       (,loop ,@inits))))

+

 (define-macro (dotimes var . body)

   (let ((v (car var))

         (cnt (cadr var)))