import: pypi: read requirements from wheels.

* doc/guix.tex (Invoking guix import): Mention that the pypi importer
works better with "unzip".
* guix/import/pypi.scm (latest-wheel-release,
wheel-url->extracted-directory): New procedures.
* tests/pypi.scm (("pypi->guix-package, wheels"): New test.

1 files changed, 3 insertions, 1 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 46d9e77fe64..0a30b52fca9 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -4545,7 +4545,9 @@ Import metadata from the @uref{https://pypi.python.org/, Python Package
 Index}@footnote{This functionality requires Guile-JSON to be installed.
 @xref{Requirements}.}.  Information is taken from the JSON-formatted
 description available at @code{pypi.python.org} and usually includes all
-the relevant information, including package dependencies.
+the relevant information, including package dependencies.  For maximum
+efficiency, it is recommended to install the @command{unzip} utility, so
+that the importer can unzip Python wheels and gather data from them.
 
 The command below imports metadata for the @code{itsdangerous} Python
 package: