[PATCHES] import: pypi: Move generally useful procedures to utils module.

[David Thompson]

Building off of the new and improved Ruby build system, here are two
patches that add a handy RubyGems importer.

>From b60252c0c52f8ab4b096c00238acab9798ee64f4 Mon Sep 17 00:00:00 2001
From: David Thompson <address@hidden>
Date: Sun, 16 Aug 2015 21:09:19 -0400
Subject: [PATCH 1/2] import: pypi: Move generally useful procedures to utils
 module.

* guix/import/pypi.scm (make-pypi-sexp): Factorize license to symbol
  conversion code.
  (string->license, snake-case, guix-hash-url): Move from here...
* guix/import/utils.scm: ... to here.
  (license->symbol): New procedure.
---
 guix/import/pypi.scm  | 29 +----------------------------
 guix/import/utils.scm | 43 ++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 43 insertions(+), 29 deletions(-)

diff --git a/guix/import/pypi.scm b/guix/import/pypi.scm
index 10d5bad..06d21fe 100644
--- a/guix/import/pypi.scm
+++ b/guix/import/pypi.scm
@@ -31,8 +31,6 @@
   #:use-module (guix utils)
   #:use-module (guix import utils)
   #:use-module (guix import json)
-  #:use-module (guix base32)
-  #:use-module (guix hash)
   #:use-module (guix packages)
   #:use-module (guix licenses)
   #:use-module (guix build-system python)
@@ -49,16 +47,6 @@ DELIMETER."
     ((elem . rest)
      (cons* elem delimiter (join rest delimiter)))))
 
-(define string->license
-  (match-lambda
-   ("GNU LGPL" lgpl2.0)
-   ("GPL" gpl3)
-   ((or "BSD" "BSD License") bsd-3)
-   ((or "MIT" "MIT license" "Expat license") expat)
-   ("Public domain" public-domain)
-   ("Apache License, Version 2.0" asl2.0)
-   (_ #f)))
-
 (define (pypi-fetch name)
   "Return an alist representation of the PyPI metadata for the package NAME,
 or #f on failure."
@@ -75,15 +63,6 @@ or #f on failure."
                (assoc-ref* pypi-package "info" "name")
                (assoc-ref* pypi-package "info" "version")))))
 
-(define (snake-case str)
-  "Return a downcased version of the string STR where underscores are replaced
-with dashes."
-  (string-join (string-split (string-downcase str) #\_) "-"))
-
-(define (guix-hash-url filename)
-  "Return the hash of FILENAME in nix-base32 format."
-  (bytevector->nix-base32-string  (file-sha256 filename)))
-
 (define (python->package-name name)
   "Given the NAME of a package on PyPI, return a Guix-compliant name for the
 package."
@@ -205,13 +184,7 @@ VERSION, SOURCE-URL, HOME-PAGE, SYNOPSIS, DESCRIPTION, and 
LICENSE."
              (home-page ,home-page)
              (synopsis ,synopsis)
              (description ,description)
-             (license ,(assoc-ref `((,lgpl2.0 . lgpl2.0)
-                                    (,gpl3 . gpl3)
-                                    (,bsd-3 . bsd-3)
-                                    (,expat . expat)
-                                    (,public-domain . public-domain)
-                                    (,asl2.0 . asl2.0))
-                                  license)))))))
+             (license ,(license->symbol license)))))))
 
 (define (pypi->guix-package package-name)
   "Fetch the metadata for PACKAGE-NAME from pypi.python.org, and return the
diff --git a/guix/import/utils.scm b/guix/import/utils.scm
index 969491d..0734fa1 100644
--- a/guix/import/utils.scm
+++ b/guix/import/utils.scm
@@ -21,6 +21,8 @@
   #:use-module (ice-9 regex)
   #:use-module (srfi srfi-1)
   #:use-module (guix hash)
+  #:use-module (guix base32)
+  #:use-module (guix licenses)
   #:use-module (guix utils)
   #:use-module ((guix build download) #:prefix build:)
   #:export (factorize-uri
@@ -29,7 +31,13 @@
             flatten
             assoc-ref*
 
-            url-fetch))
+            url-fetch
+            guix-hash-url
+
+            string->license
+            license->symbol
+
+            snake-case))
 
 (define (factorize-uri uri version)
   "Factorize URI, a package tarball URI as a string, such that any occurrences
@@ -95,3 +103,36 @@ recursively apply the procedure to the sub-list."
   "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)))
+
+(define (guix-hash-url filename)
+  "Return the hash of FILENAME in nix-base32 format."
+  (bytevector->nix-base32-string (file-sha256 filename)))
+
+(define (string->license str)
+  "Convert the string STR into a license object."
+  (match str
+    ("GNU LGPL" lgpl2.0)
+    ("GPL" gpl3)
+    ((or "BSD" "BSD License") bsd-3)
+    ((or "MIT" "MIT license" "Expat license") expat)
+    ("Public domain" public-domain)
+    ((or "Apache License, Version 2.0" "Apache 2.0") asl2.0)
+    (_ #f)))
+
+(define (license->symbol license)
+  "Convert license to a symbol representing the variable the object is bound
+to in the (guix licenses) module, or #f if there is no such known license."
+  ;; TODO: Traverse list public variables in (guix licenses) instead so we
+  ;; don't have to maintain a list manualy.
+  (assoc-ref `((,lgpl2.0 . lgpl2.0)
+               (,gpl3 . gpl3)
+               (,bsd-3 . bsd-3)
+               (,expat . expat)
+               (,public-domain . public-domain)
+               (,asl2.0 . asl2.0))
+             license))
+
+(define (snake-case str)
+  "Return a downcased version of the string STR where underscores are replaced
+with dashes."
+  (string-join (string-split (string-downcase str) #\_) "-"))
-- 
2.4.3

>From 683a434d7ee88667a218dd1494f1fee53c83fb5a Mon Sep 17 00:00:00 2001
From: David Thompson <address@hidden>
Date: Sun, 16 Aug 2015 21:15:45 -0400
Subject: [PATCH 2/2] import: Add Ruby gem importer.

* gnu/scripts/import.scm (importers): Add "gem".
* gnu/import/gem.scm: New file.
* gnu/scripts/import/gem.scm: New file.
* Makefile.am (MODULES): Add them.
---
 Makefile.am                 |  3 +-
 guix/import/gem.scm         | 97 +++++++++++++++++++++++++++++++++++++++++++++
 guix/scripts/import.scm     |  2 +-
 guix/scripts/import/gem.scm | 91 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 191 insertions(+), 2 deletions(-)
 create mode 100644 guix/import/gem.scm
 create mode 100644 guix/scripts/import/gem.scm

diff --git a/Makefile.am b/Makefile.am
index ada4cbe..f9203ec 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -213,7 +213,8 @@ MODULES +=                                  \
   guix/import/pypi.scm                         \
   guix/scripts/import/pypi.scm                 \
   guix/import/cpan.scm                         \
-  guix/scripts/import/cpan.scm
+  guix/scripts/import/gem.scm                  \
+  guix/import/gem.scm
 
 SCM_TESTS +=                                   \
   tests/pypi.scm                               \
diff --git a/guix/import/gem.scm b/guix/import/gem.scm
new file mode 100644
index 0000000..a0115f5
--- /dev/null
+++ b/guix/import/gem.scm
@@ -0,0 +1,97 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 David Thompson <address@hidden>
+;;;
+;;; 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 gem)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 pretty-print)
+  #:use-module (json)
+  #:use-module (web uri)
+  #:use-module (guix utils)
+  #:use-module (guix import utils)
+  #:use-module (guix import json)
+  #:use-module (guix packages)
+  #:use-module (guix licenses)
+  #:export (gem->guix-package))
+
+(define (rubygems-fetch name)
+  "Return an alist representation of the RubyGems metadata for the package 
NAME,
+or #f on failure."
+  (json-fetch
+   (string-append "https://rubygems.org/api/v1/gems/"; name ".json")))
+
+(define (ruby-package-name name)
+  "Given the NAME of a package on RubyGems, return a Guix-compliant name for
+the package."
+  (if (string-prefix? "ruby-" name)
+      (snake-case name)
+      (string-append "ruby-" (snake-case name))))
+
+(define (make-gem-sexp name version source-url home-page description
+                       dependencies licenses)
+  "Return the `package' s-expression for a Ruby package with the given NAME,
+VERSION, SOURCE-URL, HOME-PAGE, DESCRIPTION, DEPENDENCIES, and LICENSES."
+  (call-with-temporary-output-file
+   (lambda (temp port)
+     (and (url-fetch source-url temp)
+          `(package
+             (name ,(ruby-package-name name))
+             (version ,version)
+             (source (origin
+                       (method url-fetch)
+                       (uri (rubygems-uri ,name version))
+                       (sha256
+                        (base32
+                         ,(guix-hash-url temp)))))
+             (build-system ruby-build-system)
+             ,@(if (null? dependencies)
+                   '()
+                   `(propagated-inputs
+                     (,'quasiquote
+                      ,(map (lambda (name)
+                              `(,name
+                                (,'unquote
+                                 ,(string->symbol name))))
+                            dependencies))))
+             (synopsis ,description) ; nothing better to use
+             (description ,description)
+             (home-page ,home-page)
+             (license ,(match licenses
+                         ((license) (license->symbol license))
+                         (_ (map license->symbol licenses)))))))))
+
+(define (gem->guix-package package-name)
+  "Fetch the metadata for PACKAGE-NAME from rubygems.org, and return the
+`package' s-expression corresponding to that package, or #f on failure."
+  (let ((package (rubygems-fetch package-name)))
+    (and package
+         (let ((name         (assoc-ref package "name"))
+               (version      (assoc-ref package "version"))
+               (source-url   (assoc-ref package "gem_uri"))
+               (description  (assoc-ref package "info"))
+               (home-page    (assoc-ref package "homepage_uri"))
+               (dependencies (map (lambda (dep)
+                                    (let ((name (assoc-ref dep "name")))
+                                      (if (string=? name "bundler")
+                                          "bundler" ; special case, no prefix
+                                          (ruby-package-name name))))
+                                  (assoc-ref* package "dependencies"
+                                              "runtime")))
+               (licenses     (map string->license
+                                  (assoc-ref package "licenses"))))
+           (make-gem-sexp name version source-url home-page
+                          description dependencies licenses)))))
diff --git a/guix/scripts/import.scm b/guix/scripts/import.scm
index d0bdec1..6cd762a 100644
--- a/guix/scripts/import.scm
+++ b/guix/scripts/import.scm
@@ -73,7 +73,7 @@ rather than \\n."
 ;;; Entry point.
 ;;;
 
-(define importers '("gnu" "nix" "pypi" "cpan" "hackage" "elpa"))
+(define importers '("gnu" "nix" "pypi" "cpan" "hackage" "elpa" "gem"))
 
 (define (resolve-importer name)
   (let ((module (resolve-interface
diff --git a/guix/scripts/import/gem.scm b/guix/scripts/import/gem.scm
new file mode 100644
index 0000000..9f8094f
--- /dev/null
+++ b/guix/scripts/import/gem.scm
@@ -0,0 +1,91 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 David Thompson <address@hidden>
+;;;
+;;; 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 gem)
+  #:use-module (guix ui)
+  #:use-module (guix utils)
+  #:use-module (guix import gem)
+  #: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-gem))
+
+
+;;;
+;;; Command-line options.
+;;;
+
+(define %default-options
+  '())
+
+(define (show-help)
+  (display (_ "Usage: guix import gem PACKAGE-NAME
+Import and convert the RubyGems package for PACKAGE-NAME.\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.
+  (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 pypi")))
+         %standard-import-options))
+
+
+;;;
+;;; Entry point.
+;;;
+
+(define (guix-import-gem . 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 (gem->guix-package package-name)))
+         (unless sexp
+           (leave (_ "failed to download meta-data for package '~a'~%")
+                  package-name))
+         sexp))
+      (()
+       (leave (_ "too few arguments~%")))
+      ((many ...)
+       (leave (_ "too many arguments~%"))))))
-- 
2.4.3

-- 
David Thompson
GPG Key: 0FF1D807