monads: Add 'package->cross-derivation' and #:target for 'package-file'.

* guix/monads.scm (package-file): Add #:target keyword parameter and
  honor it.
  (package->cross-derivation): New procedure.
* tests/monads.scm ("package-file + package->cross-derivation"): New test.
* doc/guix.texi (The Store Monad): Update 'package-file' documentation.
  Add 'package->cross-derivation'.

1 files changed, 11 insertions, 0 deletions

diff --git a/tests/monads.scm b/tests/monads.scm
index ea3e4006ab..78a014ea6a 100644
--- a/tests/monads.scm
+++ b/tests/monads.scm
@@ -24,6 +24,7 @@
                 #:select (package-derivation %current-system))
   #:use-module (gnu packages)
   #:use-module (gnu packages bootstrap)
+  #:use-module ((gnu packages base) #:select (coreutils))
   #:use-module (ice-9 match)
   #:use-module (rnrs io ports)
   #:use-module (srfi srfi-1)
@@ -108,6 +109,16 @@
                       guile)))
     #:guile-for-build (package-derivation %store %bootstrap-guile)))
 
+(test-assert "package-file + package->cross-derivation"
+  (run-with-store %store
+    (mlet* %store-monad ((file (package-file coreutils "bin/ls"
+                                             #:target "foo64-gnu"))
+                         (xcu  (package->cross-derivation coreutils
+                                                          "foo64-gnu")))
+      (let ((output (derivation->output-path xcu)))
+        (return (string=? file (string-append output "/bin/ls")))))
+    #:guile-for-build (package-derivation %store %bootstrap-guile)))
+
 (test-assert "interned-file"
   (run-with-store %store
     (mlet* %store-monad ((file -> (search-path %load-path "guix.scm"))