packages: Add 'package-definition-location'.

Suggested by Maxime Devos <maximedevos@telenet.be>.

* guix/packages.scm (current-definition-location): New syntax parameter.
(define-public*): New macro.
(<package>)[definition-location]: New field.
(package-definition-location): New procedure.
* tests/packages.scm ("package-definition-location"): New test.

1 files changed, 11 insertions, 0 deletions

diff --git a/tests/packages.scm b/tests/packages.scm
index 2a290bc353..3756877270 100644
--- a/tests/packages.scm
+++ b/tests/packages.scm
@@ -236,6 +236,17 @@
                 (eq? item new)))
              (null? (manifest-transaction-remove tx)))))))
 
+(test-assert "package-definition-location"
+  (let ((location   (package-location hello))
+        (definition (package-definition-location hello)))
+    ;; Check for the usual layout of (define-public hello (package ...)).
+    (and (string=? (location-file location)
+                   (location-file definition))
+         (= 0 (location-column definition))
+         (= 2 (location-column location))
+         (= (location-line definition)
+            (- (location-line location) 1)))))
+
 (test-assert "package-field-location"
   (let ()
     (define (goto port line column)