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Inhibit duplicates in fold-packages.

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* gnu/packages.scm (fold2): New procedure.
  (fold-packages): Rework to suppress duplicates.
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Mark H Weaver 2013-02-12 20:29:30 -05:00 committed by Ludovic Courtès
parent 790b8e0ebe
commit 9ede36f0ed
1 changed files with 28 additions and 12 deletions
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40
gnu/packages.scm
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@ -1,5 +1,6 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2013 Mark H Weaver <mhw@netris.org>
;;;
;;; This file is part of GNU Guix.
;;;
@ -20,6 +21,7 @@ (define-module (gnu packages)
#:use-module (guix packages)
#:use-module (guix utils)
#:use-module (ice-9 ftw)
#:use-module (ice-9 vlist)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-39)
@ -106,20 +108,34 @@ (define not-slash
(false-if-exception (resolve-interface name))))
(package-files)))
(define (fold2 f seed1 seed2 lst)
(if (null? lst)
(values seed1 seed2)
(call-with-values
(lambda () (f (car lst) seed1 seed2))
(lambda (seed1 seed2)
(fold2 f seed1 seed2 (cdr lst))))))
(define (fold-packages proc init)
"Call (PROC PACKAGE RESULT) for each available package, using INIT as
the initial value of RESULT."
(fold (lambda (module result)
(fold (lambda (var result)
(if (package? var)
(proc var result)
result))
result
(module-map (lambda (sym var)
(false-if-exception (variable-ref var)))
module)))
init
(package-modules)))
the initial value of RESULT. It is guaranteed to never traverse the
same package twice."
(identity ; discard second return value
(fold2 (lambda (module result seen)
(fold2 (lambda (var result seen)
(if (and (package? var)
(not (vhash-assq var seen)))
(values (proc var result)
(vhash-consq var #t seen))
(values result seen)))
result
seen
(module-map (lambda (sym var)
(false-if-exception (variable-ref var)))
module)))
init
vlist-null
(package-modules))))
(define* (find-packages-by-name name #:optional version)
"Return the list of packages with the given NAME. If VERSION is not #f,