gnu: Add python-editdistance.

* gnu/packages/textutils.scm (python-editdistance): New variable.

gnu/packages/textutils.scm

@@ -38,6 +38,7 @@
   #:use-module (guix build-system gnu)
   #:use-module (guix build-system cmake)
   #:use-module (guix build-system trivial)
+  #:use-module (guix build-system python)
   #:use-module (gnu packages)
   #:use-module (gnu packages autotools)
   #:use-module (gnu packages compression)
@@ -623,3 +624,39 @@ completely with the standard @code{javax.swing.text} package.  It is fast and
 efficient, and can be used in any application that needs to edit or view
 source code.")
     (license license:bsd-3)))
+
+;; We use the sources from git instead of the tarball from pypi, because the
+;; latter does not include the Cython source file from which bycython.cpp is
+;; generated.
+(define-public python-editdistance
+  (let ((commit "3ea84a7dd3258c76aa3be851ef3d50e59c886846")
+        (revision "1"))
+    (package
+      (name "python-editdistance")
+      (version (string-append "0.3.1-" revision "." (string-take commit 7)))
+      (source
+       (origin
+         (method git-fetch)
+         (uri (git-reference
+               (url "https://github.com/aflc/editdistance.git")
+               (commit commit)))
+         (sha256
+          (base32
+           "1l43svsv12crvzphrgi6x435z6xg8m086c64armp8wzb4l8ccm7g"))))
+      (build-system python-build-system)
+      (arguments
+       `(#:phases
+         (modify-phases %standard-phases
+           (add-after 'unpack 'build-cython-code
+             (lambda _
+               (with-directory-excursion "editdistance"
+                 (delete-file "bycython.cpp")
+                 (zero? (system* "cython" "--cplus" "bycython.pyx"))))))))
+      (native-inputs
+       `(("python-cython" ,python-cython)))
+      (home-page "https://www.github.com/aflc/editdistance")
+      (synopsis "Fast implementation of the edit distance (Levenshtein distance)")
+      (description
+       "This library simply implements Levenshtein distance algorithm with C++
+and Cython.")
+      (license license:expat))))