[racket] unwrapping a list

From: Eli Barzilay (eli at barzilay.org)
Date: Mon Jun 11 15:30:16 EDT 2012

A few minutes ago, Jordan Schatz wrote:
> 
> Is there a way to unwrap or explode a list? I don't see it in the
> docs, but it seems like it would be a common thing.
> 
> This is what I want to do:
> 
> (define-values (year month day)
>   (regexp-split #rx"/" "2012/06/06"))
> 
> But regexp-split returns a list, not values, so I'd like to "unwrap"
> the list and just have the values...

    (match-define (list year month day)
      (regexp-split #rx"/" "2012/06/06"))

> (let ([year month day (regexp-split #rx"/" "2012/06/06")])
>   )
> Would be handy too...

    (match-let ([(list year month date)
                 (regexp-split #rx"/" "2012/06/06")])
      year)

-- 
          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                    http://barzilay.org/                   Maze is Life!

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