import: pypi: Support recursive importing.

* guix/import/pypi.scm (guess-requirements): Use upstream names.
(compute-inputs): Return the upstream dependency names as an additional value.
(make-pypi-sexp): Likewise.
(pypi->guix-package): Memoize it.
(pypi-recursive-import): New procedure.
* guix/scripts/import/pypi.scm (show-help, %options): Accept "recursive"
option.
(guix-import-pypi): Use pypi-recursive-import.
* doc/guix.texi (Invoking guix import): Document it.

doc/guix.texi

@@ -6442,6 +6442,14 @@ package:
 guix import pypi itsdangerous
 @end example
 
+@table @code
+@item --recursive
+@itemx -r
+Traverse the dependency graph of the given upstream package recursively
+and generate package expressions for all those packages that are not yet
+in Guix.
+@end table
+
 @item gem
 @cindex gem
 Import metadata from @uref{https://rubygems.org/,

guix/import/pypi.scm

@@ -25,6 +25,7 @@
   #:use-module (ice-9 match)
   #:use-module (ice-9 pretty-print)
   #:use-module (ice-9 regex)
+  #:use-module (ice-9 receive)
   #:use-module ((ice-9 rdelim) #:select (read-line))
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-26)
@@ -47,6 +48,7 @@
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix build-system python)
   #:export (guix-package->pypi-name
+            pypi-recursive-import
             pypi->guix-package
             %pypi-updater))
 
@@ -162,7 +164,7 @@ cannot determine package dependencies"))
                  ((or (string-null? line) (comment? line))
                   (loop result))
                  (else
-                  (loop (cons (python->package-name (clean-requirement line))
+                  (loop (cons (clean-requirement line)
                               result))))))))))
 
   (define (read-wheel-metadata wheel-archive)
@@ -182,9 +184,7 @@ cannot determine package dependencies"))
                                             (hash-ref (list-ref run_requires 0)
                                                        "requires")
                                             '())))
-                     (map (lambda (r)
-                            (python->package-name (clean-requirement r)))
-                          requirements)))))
+                     (map clean-requirement requirements)))))
              (lambda ()
                (delete-file json-file)
                (rmdir dirname))))))
@@ -237,16 +237,21 @@ cannot determine package dependencies"))
 
 (define (compute-inputs source-url wheel-url tarball)
   "Given the SOURCE-URL of an already downloaded TARBALL, return a list of
-name/variable pairs describing the required inputs of this package."
-  (sort
+name/variable pairs describing the required inputs of this package.  Also
+return the unaltered list of upstream dependency names."
+  (let ((dependencies
+         (remove (cut string=? "argparse" <>)
+                 (guess-requirements source-url wheel-url tarball))))
+    (values (sort
              (map (lambda (input)
-           (list input (list 'unquote (string->symbol input))))
-         (remove (cut string=? "python-argparse" <>)
-                 (guess-requirements source-url wheel-url tarball)))
+                    (let ((guix-name (python->package-name input)))
+                      (list guix-name (list 'unquote (string->symbol guix-name)))))
+                  dependencies)
              (lambda args
                (match args
                  (((a _ ...) (b _ ...))
-         (string-ci<? a b))))))
+                  (string-ci<? a b)))))
+            dependencies)))
 
 (define (make-pypi-sexp name version source-url wheel-url home-page synopsis
                         description license)
@@ -255,6 +260,9 @@ VERSION, SOURCE-URL, HOME-PAGE, SYNOPSIS, DESCRIPTION, and LICENSE."
   (call-with-temporary-output-file
    (lambda (temp port)
      (and (url-fetch source-url temp)
+          (receive (input-package-names upstream-dependency-names)
+              (compute-inputs source-url wheel-url temp)
+            (values
              `(package
                 (name ,(python->package-name name))
                 (version ,version)
@@ -269,13 +277,16 @@ VERSION, SOURCE-URL, HOME-PAGE, SYNOPSIS, DESCRIPTION, and LICENSE."
                            (base32
                             ,(guix-hash-url temp)))))
                 (build-system python-build-system)
-             ,@(maybe-inputs (compute-inputs source-url wheel-url temp))
+                ,@(maybe-inputs input-package-names)
                 (home-page ,home-page)
                 (synopsis ,synopsis)
                 (description ,description)
-             (license ,(license->symbol license)))))))
+                (license ,(license->symbol license)))
+             upstream-dependency-names))))))
 
-(define (pypi->guix-package package-name)
+(define pypi->guix-package
+  (memoize
+   (lambda* (package-name)
      "Fetch the metadata for PACKAGE-NAME from pypi.org, and return the
 `package' s-expression corresponding to that package, or #f on failure."
      (let ((package (pypi-fetch package-name)))
@@ -294,7 +305,13 @@ VERSION, SOURCE-URL, HOME-PAGE, SYNOPSIS, DESCRIPTION, and LICENSE."
                     (home-page (assoc-ref* package "info" "home_page"))
                     (license (string->license (assoc-ref* package "info" "license"))))
                 (make-pypi-sexp name version release wheel home-page synopsis
-                             description license))))))
+                                description license))))))))
+
+(define (pypi-recursive-import package-name)
+  (recursive-import package-name #f
+                    #:repo->guix-package (lambda (name repo)
+                                           (pypi->guix-package name))
+                    #:guix-name python->package-name))
 
 (define (string->license str)
   "Convert the string STR into a license object."

guix/scripts/import/pypi.scm

@@ -1,5 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2014 David Thompson <davet@gnu.org>
+;;; Copyright © 2018 Ricardo Wurmus <rekado@elephly.net>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -25,6 +26,7 @@
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-37)
+  #:use-module (srfi srfi-41)
   #:use-module (ice-9 match)
   #:use-module (ice-9 format)
   #:export (guix-import-pypi))
@@ -43,6 +45,8 @@ Import and convert the PyPI package for PACKAGE-NAME.\n"))
   (display (G_ "
   -h, --help             display this help and exit"))
   (display (G_ "
+  -r, --recursive        import packages recursively"))
+  (display (G_ "
   -V, --version          display version information and exit"))
   (newline)
   (show-bug-report-information))
@@ -56,6 +60,9 @@ Import and convert the PyPI package for PACKAGE-NAME.\n"))
          (option '(#\V "version") #f #f
                  (lambda args
                    (show-version-and-exit "guix import pypi")))
+         (option '(#\r "recursive") #f #f
+                 (lambda (opt name arg result)
+                   (alist-cons 'recursive #t result)))
          %standard-import-options))
 
 
@@ -81,11 +88,22 @@ Import and convert the PyPI package for PACKAGE-NAME.\n"))
                            (reverse opts))))
     (match args
       ((package-name)
+       (if (assoc-ref opts 'recursive)
+           ;; Recursive import
+           (map (match-lambda
+                  ((and ('package ('name name) . rest) pkg)
+                   `(define-public ,(string->symbol name)
+                      ,pkg))
+                  (_ #f))
+                (reverse
+                 (stream->list
+                  (pypi-recursive-import package-name))))
+           ;; Single import
            (let ((sexp (pypi->guix-package package-name)))
              (unless sexp
                (leave (G_ "failed to download meta-data for package '~a'~%")
                       package-name))
-         sexp))
+             sexp)))
       (()
        (leave (G_ "too few arguments~%")))
       ((many ...)