1 files changed, 124 insertions, 0 deletions
diff --git a/guix/scripts/import.scm b/guix/scripts/import.scm
new file mode 100644
index 0000000000..0bc6926c66
--- /dev/null
+++ b/guix/scripts/import.scm
@@ -0,0 +1,124 @@
+;;; 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 scripts import)
+  #:use-module (guix ui)
+  #:use-module (guix snix)
+  #:use-module (guix utils)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-11)
+  #:use-module (srfi srfi-26)
+  #:use-module (srfi srfi-37)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 pretty-print)
+  #:export (guix-import))
+
+
+;;;
+;;; Helper.
+;;;
+
+(define (newline-rewriting-port output)
+  "Return an output port that rewrites strings containing the \\n escape
+to an actual newline.  This works around the behavior of `pretty-print'
+and `write', which output these as \\n instead of actual newlines,
+whereas we want the `description' field to contain actual newlines
+rather than \\n."
+  (define (write-string str)
+    (let loop ((chars (string->list str)))
+      (match chars
+        (()
+         #t)
+        ((#\\ #\n rest ...)
+         (newline output)
+         (loop rest))
+        ((chr rest ...)
+         (write-char chr output)
+         (loop rest)))))
+
+  (make-soft-port (vector (cut write-char <>)
+                          write-string
+                          (lambda _ #t)           ; flush
+                          #f
+                          (lambda _ #t)           ; close
+                          #f)
+                  "w"))
+
+
+;;;
+;;; Command-line options.
+;;;
+
+(define %default-options
+  '())
+
+(define (show-help)
+  (display (_ "Usage: guix import NIXPKGS ATTRIBUTE
+Import and convert the Nix expression ATTRIBUTE of NIXPKGS.\n"))
+  (display (_ "
+  -h, --help             display this help and exit"))
+  (display (_ "
+  -V, --version          display version information and exit"))
+  (newline)
+  (show-bug-report-information))
+
+(define %options
+  ;; Specification of the command-line options.
+  (list (option '(#\h "help") #f #f
+                (lambda args
+                  (show-help)
+                  (exit 0)))
+        (option '(#\V "version") #f #f
+                (lambda args
+                  (show-version-and-exit "guix-import")))))
+
+
+;;;
+;;; Entry point.
+;;;
+
+(define (guix-import . args)
+  (define (parse-options)
+    ;; Return the alist of option values.
+    (args-fold args %options
+               (lambda (opt name arg result)
+                 (leave (_ "~A: unrecognized option~%") name))
+               (lambda (arg result)
+                 (alist-cons 'argument arg result))
+               %default-options))
+
+  (install-locale)
+  (textdomain "guix")
+  (setvbuf (current-output-port) _IOLBF)
+  (setvbuf (current-error-port) _IOLBF)
+
+  (let* ((opts (parse-options))
+         (args (filter-map (match-lambda
+                            (('argument . value)
+                             value)
+                            (_ #f))
+                           (reverse opts))))
+    (match args
+      ((nixpkgs attribute)
+       (let-values (((expr loc)
+                     (nixpkgs->guix-package nixpkgs attribute)))
+         (format #t ";; converted from ~a:~a~%~%"
+                 (location-file loc) (location-line loc))
+         (pretty-print expr (newline-rewriting-port (current-output-port)))))
+      (_
+       (leave (_ "wrong number of arguments~%"))))))