derivations: 'derivation' and related procedures return a single value.

* guix/derivations.scm (derivation->output-path,
  derivation->output-paths): New procedures.
  (derivation-path->output-path): Use 'derivation->output-path'.
  (derivation-path->output-paths): Use 'derivation->output-paths'.
  (derivation): Accept 'derivation?' objects as inputs.  Return a single
  value.
  (build-derivations): New procedure.
  (compiled-modules): Use 'derivation->output-paths'.
  (build-expression->derivation)[source-path]: Add case for when the
  input matches 'derivation?'.
  [prologue]: Accept 'derivation?' objects in INPUTS.
  [mod-dir, go-dir]: Use 'derivation->output-path'.
* guix/download.scm (url-fetch): Adjust to the single-value return.
* guix/packages.scm (package-output): Use 'derivation->output-path'.
* guix/scripts/build.scm (guix-build): When the argument is
  'derivation-path?', pass it through 'read-derivation'.
  Use 'derivation-file-name' to print out the .drv file names, and to
  register them.  Use 'derivation->output-path' instead of
  'derivation-path->output-path'.
* guix/scripts/package.scm (roll-back): Adjust to the single-value
  return.
  (guix-package): Use 'derivation->output-path'.
* guix/ui.scm (show-what-to-build): Adjust to deal with 'derivation?'
  objects instead of .drv file names.
* gnu/system/grub.scm (grub-configuration-file): Use
  'derivation->output-path' instead of 'derivation-path->output-path'.
* gnu/system/vm.scm (qemu-image, system-qemu-image): Likewise.
* tests/builders.scm, tests/derivations.scm, tests/packages.scm,
  tests/store.scm, tests/union.scm: Adjust to the new calling
  convention.
* doc/guix.texi (Defining Packages, The Store, Derivations): Adjust
  accordingly.

1 files changed, 4 insertions, 4 deletions

diff --git a/tests/builders.scm b/tests/builders.scm
index 1e6b62ee6a..0ed5d74a22 100644
--- a/tests/builders.scm
+++ b/tests/builders.scm
@@ -70,10 +70,10 @@
                      "ftp://ftp.gnu.org/gnu/hello/hello-2.8.tar.gz"))
          (hash     (nix-base32-string->bytevector
                     "0wqd8sjmxfskrflaxywc7gqw7sfawrfvdxd9skxawzfgyy0pzdz6"))
-         (drv-path (url-fetch %store url 'sha256 hash
+         (drv      (url-fetch %store url 'sha256 hash
                               #:guile %bootstrap-guile))
-         (out-path (derivation-path->output-path drv-path)))
-    (and (build-derivations %store (list drv-path))
+         (out-path (derivation->output-path drv)))
+    (and (build-derivations %store (list drv))
          (file-exists? out-path)
          (valid-path? %store out-path))))
 
@@ -93,7 +93,7 @@
                               #:implicit-inputs? #f
                               #:guile %bootstrap-guile
                               #:search-paths %bootstrap-search-paths))
-         (out      (derivation-path->output-path build)))
+         (out      (derivation->output-path build)))
     (and (build-derivations %store (list (pk 'hello-drv build)))
          (valid-path? %store out)
          (file-exists? (string-append out "/bin/hello")))))