package: Add --manifest option.

* guix/scripts/package.scm (show-help): Add help text.
  (%options): Add manifest option.
  (guix-package): Add manifest option handler.
* doc/guix.texi ("Invoking guix package"): Document it.
* tests/guix-package.sh: Add test.

1 files changed, 17 insertions, 0 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 53c9fb2d44..9b2e367d0c 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -1068,6 +1068,23 @@ substring ``emacs'':
 $ guix package --upgrade . --do-not-upgrade emacs
 @end example
 
+@item --manifest=@var{file}
+@itemx -m @var{file}
+Create a new @dfn{generation} of the profile from the manifest object
+returned by the Scheme code in @var{file}.
+
+A manifest file may look like this:
+
+@example
+(use-package-modules guile emacs gcc)
+
+(packages->manifest
+ (list guile-2.0
+       emacs
+       ;; Use a specific package output.
+       (list gcc "debug")))
+@end example
+
 @item --roll-back
 Roll back to the previous @dfn{generation} of the profile---i.e., undo
 the last transaction.