Inhibit duplicates in fold-packages.

* gnu/packages.scm (fold2): New procedure.
  (fold-packages): Rework to suppress duplicates.
This commit is contained in:
Mark H Weaver 2013-02-12 20:29:30 -05:00 committed by Ludovic Courtès
parent 790b8e0ebe
commit 9ede36f0ed

View file

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