issue: Add authors function returning all authors.

* tissue/issue.scm (authors): New public function.

1 files changed, 16 insertions, 0 deletions

diff --git a/tissue/issue.scm b/tissue/issue.scm
index 8d1d11c..91585a7 100644
--- a/tissue/issue.scm
+++ b/tissue/issue.scm
@@ -48,6 +48,7 @@
             post-author
             post-date
             post-relative-date
+            authors
             issues))
 
 (define %aliases
@@ -132,6 +133,21 @@ return #f."
   (time-monotonic->date
    (make-time time-monotonic 0 timestamp)))
 
+(define authors
+  (memoize-thunk
+   (lambda ()
+     "Return a list of all authors who have committed to this git
+repository."
+     (delete-duplicates
+      (map (cut resolve-alias <> (%aliases))
+           (call-with-input-pipe
+            (lambda (port)
+              (port-transduce (tmap (lambda (line)
+                                      (match (string-split line #\tab)
+                                        ((_ author) author))))
+                              rcons get-line port))
+            "git" "shortlog" "--summary"))))))
+
 (define (resolve-alias name aliases)
   "Resolve NAME against ALIASES, a list of aliases. ALIASES should be
 in the form of the argument of the same name to `tissue-configuration'