Thanks Neil and Richard !<div><br></div><div>Now that I look at your solutions, it looks so straightforward. Can't believe it didn't occur to me. <br><div><br></div><div><br><br><div class="gmail_quote">On Sat, Apr 30, 2011 at 7:31 AM, Neil Van Dyke <span dir="ltr"><<a href="mailto:neil@neilvandyke.org">neil@neilvandyke.org</a>></span> wrote:<br> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">nikhil wrote at 04/30/2011 03:16 AM:<div class="im"><br> <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> In my case, I have an incoming function which takes 4 arguments and I need to generate a function which takes in 5 args when a condition satisfies, if not then the original 4 args .<br> </blockquote> <br></div> >From looking at the example you provided, two ways come to mind immediately. Either way is fine. Which you use depends on the circumstances, including code maintainability.<br> <br> #lang racket<br> <br> (define (f? x)<br> ;; This is just a placeholder for "f?".<br> #t)<br> <br> (define (condition?)<br> ;; This is just a placeholder for "condition?".<br> (zero? (random 2)))<br> <br> ;; This uses ",@" splicing.<br> (define (parse-func-1 exp)<br> (let ((x1 'x1) (x2 'x2) (x3 'x3) (x4 'x4))<div class="im"><br> (cond<br> [(f? exp)<br> `(FF<br> ,x1<br> ,x2<br> ,@(if (condition?)<br> '(xNEW)<br> '())<br> ,x3<br></div> ,x4)])))<br> <br> ;; This moves the "if" higher up.<br> (define (parse-func-2 exp)<br> (let ((x1 'x1) (x2 'x2) (x3 'x3) (x4 'x4))<br> (cond<br> [(f? exp)<br> (if (condition?)<br> `(FF<div class="im"><br> ,x1<br> ,x2<br> xNEW<br> ,x3<br> ,x4)<br></div> `(FF<br> ,x1<br> ,x2<br> ,x3<br> ,x4))])))<br><font color="#888888"> <br> <br> <br> -- <br> <a href="http://www.neilvandyke.org/" target="_blank">http://www.neilvandyke.org/</a><br> </font></blockquote></div><br></div></div>