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From: Nikita Karetnikov <nikita@karetnikov.org>
To: "Ludovic Courtès" <ludo@gnu.org>
Cc: bug-guix@gnu.org
Subject: Re: Faster!
Date: Mon, 04 Feb 2013 14:12:20 -0500	[thread overview]
Message-ID: <87fw1byjti.fsf@karetnikov.org> (raw)
In-Reply-To: <87622dgfgj.fsf@gnu.org> ("Ludovic Courtès"'s message of "(unknown date)")

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While we are at it, will it be better to rewrite 'fold-packages' and
similar things (like 'search') using streams?

For example:

  #:use-module (ice-9 streams)

[...]

(define (fold-packages-lazy proc init)
  "Call (PROC PACKAGE RESULT) for each available package, using INIT as
the initial value of RESULT."
  (stream-fold
   (lambda (module result)
     (stream-fold (lambda (var result)
                    (if (package? var)
                        (proc var result)
                        result))
                  result
                  (list->stream
                   (module-map (lambda (sym var)
                                 (false-if-exception (variable-ref var)))
                               module))))
   init
   (list->stream (package-modules))))

'time' shows that the above is a bit slower than the current version.
Will it be faster when we have more packages?  What about memory?

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  reply	other threads:[~2013-02-04 19:12 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-29 23:15 Faster! Ludovic Courtès
2013-01-30 20:47 ` Faster! Andreas Enge
2013-01-30 21:04   ` Faster! Ludovic Courtès
2013-01-30 21:17     ` Faster! Andreas Enge
2013-01-30 22:04       ` Faster! Ludovic Courtès
2013-01-30 22:09         ` Faster! Andreas Enge
2013-01-30 22:51           ` Faster! Ludovic Courtès
2013-01-31 22:22             ` Faster! Ludovic Courtès
2013-02-04 19:12               ` Nikita Karetnikov [this message]
2013-02-04 21:37                 ` Faster! Ludovic Courtès
2013-03-16 16:43     ` Faster! Ludovic Courtès

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