[racket] Printing multiple stmts in cond

(if (condition? data)
    (FF x1 x2 xNEW x3 x4)
    (f x1 x2 x3 x4))

The result of one of them is returned.

rac


On Apr 30, 2011, at 1:16 AM, nikhil wrote:

> Ok. Here's what I am trying to do.
> 
> I am parsing incoming racket code and generating back racket code. 
> 
> 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 .
> 
> Something like,
> 
> Input--> 
> (f x1 x2 x3 x4)
> 
> Output-->
> (FF x1 x2 xNEW x3 x4)
> 
> --------------------------------------------------
> 
> (define (parse-func exp)
>    (cond
> ............
> 
>    [(f? exp)
>        `(FF
>          ,x1
>          ,x2
>          ,(if (condition?)
>               xNEW)
>        
>          ,x3
>          ,x4)]
> 
> (The above is just pseudo-code) As shown above, when the if condition fails I just want 4 args. But a default #<void> is passed instead when used with cond. 
> 
> I am new to racket and functional programing in general, so I am not able to express my problem very accurately :(
> Hope the above example is clear enough to explain what I am doing. 
> 
> 
> 
> On Sat, Apr 30, 2011 at 7:00 AM, Neil Van Dyke <neil at neilvandyke.org> wrote:
> nikhil wrote at 04/30/2011 02:52 AM:
> 
> Basically, I dont want to execute an else stmt or return multiple values. I just want to return "stmt1" if condition satisfies and dont do anything if false. No returning #<void> or anything.
> 
> An expression always produces at least one value, even if the value is the void value.  (Usually, a REPL will hide a returned void value from you, but a void value is still being returned, which can be confusing.)
> 
> If you can show *why* you don't want to produce *any* value, then people can show you different ways to write that code.
> 
> -- 
> http://www.neilvandyke.org/
> 
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