gexp: Add 'lower-object'.

* guix/gexp.scm (lower-object): New procedure.
  (lower-inputs, lower-references, gexp->sexp): Use it.
* tests/gexp.scm ("lower-object"): New test.
* doc/guix.texi (G-Expressions): Document it.

1 files changed, 7 insertions, 0 deletions

diff --git a/tests/gexp.scm b/tests/gexp.scm
index 0749811ea8..492f3d6d89 100644
--- a/tests/gexp.scm
+++ b/tests/gexp.scm
@@ -654,6 +654,13 @@
     (parameterize ((%current-target-system "fooooo"))
       (derivation? (run-with-store %store mval)))))
 
+(test-assertm "lower-object"
+  (mlet %store-monad ((drv1 (lower-object %bootstrap-guile))
+                      (drv2 (lower-object (package-source coreutils)))
+                      (item (lower-object (plain-file "foo" "Hello!"))))
+    (return (and (derivation? drv1) (derivation? drv2)
+                 (store-path? item)))))
+
 (test-assert "printer"
   (string-match "^#<gexp \\(string-append .*#<package coreutils.*\
  \"/bin/uname\"\\) [[:xdigit:]]+>$"