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[racket] Unreachable line reached

From: Paulo J. Matos (paulo at matos-sorge.com)
Date: Mon Sep 17 13:53:23 EDT 2012		 
On 17/09/12 18:30, Danny Yoo wrote:
>> I have a trivial question but I desperately need a spare pair or eyes (or
>> another brain).
>
> The 'when's here look really suspicious.  You want control flow to go
> exclusively to one or the other path, but when you have 'when' like
> this:
>
>
>      ... (when <test> <body>) <rest>
>
> unless an exception occurs in the <test> or <body>, control flow will
> inevitably go through <rest> as well.  And I suspect you _don't_ want
> that in your use in the snippet.
>

Even before trying your solution (which I am pretty sure it will ok), 
let me ask you to confirm my suspicion.

Initially my idea was:
  (when <cond>
     <stmt>s
     (loop (read-line in)))
  <rest>

If <cond> is true, <rest> will never execute because we are looping with 
read-line.

However, after your email I can see that after (loop (read-line in)) 
finishes <rest> is going to be executed. And this _has_ to be executed 
unless there was a return or exception in the function, but since we are 
in Racket and I am not playing with call/cc, <rest> will be executed no 
matter what.

As you can see, I have been doing imperative languages for too long now. 
Need to get back into racket. :)

Thanks,

-- 
PMatos
Posted on the users mailing list.