guix-devel/guix/import/utils.scm

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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix import utils)
#:use-module (ice-9 match)
#:use-module (ice-9 regex)
#:use-module (srfi srfi-1)
#:use-module (guix hash)
#:use-module (guix utils)
#:use-module ((guix build download) #:prefix build:)
#:export (factorize-uri
hash-table->alist
flatten
assoc-ref*
url-fetch))
(define (factorize-uri uri version)
"Factorize URI, a package tarball URI as a string, such that any occurrences
of the string VERSION is replaced by the symbol 'version."
(let ((version-rx (make-regexp (regexp-quote version))))
(match (regexp-exec version-rx uri)
(#f
uri)
(_
(let ((indices (fold-matches version-rx uri
'((0))
(lambda (m result)
(match result
(((start) rest ...)
`((,(match:end m))
(,start . ,(match:start m))
,@rest)))))))
(fold (lambda (index result)
(match index
((start)
(cons (substring uri start)
result))
((start . end)
(cons* (substring uri start end)
'version
result))))
'()
indices))))))
(define (hash-table->alist table)
"Return an alist represenation of TABLE."
(map (match-lambda
((key . (lst ...))
(cons key
(map (lambda (x)
(if (hash-table? x)
(hash-table->alist x)
x))
lst)))
((key . (? hash-table? table))
(cons key (hash-table->alist table)))
(pair pair))
(hash-map->list cons table)))
(define (flatten lst)
"Return a list that recursively concatenates all sub-lists of LST."
(fold-right
(match-lambda*
(((sub-list ...) memo)
(append (flatten sub-list) memo))
((elem memo)
(cons elem memo)))
'() lst))
(define (assoc-ref* alist key . rest)
"Return the value for KEY from ALIST. For each additional key specified,
recursively apply the procedure to the sub-list."
(if (null? rest)
(assoc-ref alist key)
(apply assoc-ref* (assoc-ref alist key) rest)))
(define (url-fetch url file-name)
"Save the contents of URL to FILE-NAME. Return #f on failure."
(parameterize ((current-output-port (current-error-port)))
(build:url-fetch url file-name)))