import: Add stackage importer and updater.

* guix/import/stackage.scm: New file.
* guix/scripts/import/stackage.scm: New file.
* Makefile.am (MODULES): Add new files.
* guix/scripts/import.scm (importers): Add "stackage".
* guix/scripts/refresh.scm (%updaters): Add %stackage-updater.
* doc/guix.texi (Invoking 'guix import'): Document the importer.
  (Invoking 'guix refresh'): Add stackage to option --type valid values.
* guix/import/hackage.scm (guix-package->hackage-name, hackage-fetch,
  hackage-source-url, hackage-cabal-url, hackage-package?): Export them.

3 files changed, 118 insertions, 1 deletions

diff --git a/guix/scripts/import.scm b/guix/scripts/import.scm
index 4d07e0fd69..8c2f705738 100644
--- a/guix/scripts/import.scm
+++ b/guix/scripts/import.scm
@@ -73,7 +73,8 @@ rather than \\n."
 ;;; Entry point.
 ;;;
 
-(define importers '("gnu" "nix" "pypi" "cpan" "hackage" "elpa" "gem" "cran" "crate"))
+(define importers '("gnu" "nix" "pypi" "cpan" "hackage" "stackage" "elpa" "gem"
+                    "cran" "crate"))
 
 (define (resolve-importer name)
   (let ((module (resolve-interface
diff --git a/guix/scripts/import/stackage.scm b/guix/scripts/import/stackage.scm
new file mode 100644
index 0000000000..cf47bff259
--- /dev/null
+++ b/guix/scripts/import/stackage.scm
@@ -0,0 +1,115 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2017 Federico Beffa <beffa@fbengineering.ch>
+;;;
+;;; 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 stackage)
+  #:use-module (guix ui)
+  #:use-module (guix utils)
+  #:use-module (guix packages)
+  #:use-module (guix scripts)
+  #:use-module (guix import stackage)
+  #:use-module (guix scripts import)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-11)
+  #:use-module (srfi srfi-37)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 format)
+  #:export (guix-import-stackage))
+
+
+;;;
+;;; Command-line options.
+;;;
+
+(define %default-options
+  `((lts-version . "")
+    (include-test-dependencies? . #t)))
+
+(define (show-help)
+  (display (_ "Usage: guix import stackage PACKAGE-NAME
+Import and convert the LTS Stackage package for PACKAGE-NAME.\n"))
+  (display (_ "
+  -r VERSION, --lts-version=VERSION
+                               specify the LTS version to use"))
+  (display (_ "
+  -h, --help                   display this help and exit"))
+  (display (_ "
+  -t, --no-test-dependencies   don't include test-only dependencies"))
+  (display (_ "
+  -V, --version                display version information and exit"))
+  (newline)
+  (show-bug-report-information))
+
+(define %options
+  ;; Specification of the command-line options.
+  (cons* (option '(#\h "help") #f #f
+                 (lambda args
+                   (show-help)
+                   (exit 0)))
+         (option '(#\V "version") #f #f
+                 (lambda args
+                   (show-version-and-exit "guix import stackage")))
+         (option '(#\t "no-test-dependencies") #f #f
+                 (lambda (opt name arg result)
+                   (alist-cons 'include-test-dependencies? #f
+                               (alist-delete 'include-test-dependencies?
+                                             result))))
+         (option '(#\r "lts-version") #t #f
+                 (lambda (opt name arg result)
+                   (alist-cons 'lts-version arg
+                               (alist-delete 'lts-version
+                                             result))))
+         %standard-import-options))
+
+
+;;;
+;;; Entry point.
+;;;
+
+(define (guix-import-stackage . 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))
+
+  (let* ((opts (parse-options))
+         (args (filter-map (match-lambda
+                            (('argument . value)
+                             value)
+                            (_ #f))
+                           (reverse opts))))
+    (match args
+      ((package-name)
+       (let ((sexp (stackage->guix-package
+                    package-name
+                    #:include-test-dependencies?
+                    (assoc-ref opts 'include-test-dependencies?)
+                    #:lts-version (assoc-ref opts 'lts-version))))
+         (unless sexp
+           (leave (_ "failed to download cabal file for package '~a'~%")
+                  package-name))
+         sexp))
+      (()
+       (leave (_ "too few arguments~%")))
+      ((many ...)
+       (leave (_ "too many arguments~%"))))))
+
+;;; stackage.scm ends here
diff --git a/guix/scripts/refresh.scm b/guix/scripts/refresh.scm
index 0dd7eee974..4d3c695aaf 100644
--- a/guix/scripts/refresh.scm
+++ b/guix/scripts/refresh.scm
@@ -205,6 +205,7 @@ unavailable optional dependencies such as Guile-JSON."
                  %elpa-updater
                  %cran-updater
                  %bioconductor-updater
+                 ((guix import stackage) => %stackage-updater)
                  %hackage-updater
                  ((guix import cpan) => %cpan-updater)
                  ((guix import pypi) => %pypi-updater)