04/04: monads: Fix 'liftN' fallback case.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit dbbc248aeef1bc3b5d76268782acff43e9d71d57
Author: Ludovic Courtès <address@hidden>
Date:   Fri Sep 4 18:31:06 2015 +0200

    monads: Fix 'liftN' fallback case.
    
    Reported by Andy Wingo <address@hidden>.
    
    * guix/monads.scm (define-lift) <fallback case>: Add missing #'.  Remove
      extra formal parameter.
    * tests/monads.scm ("lift"): Add test with 'lift1' as a procedure.
---
 guix/monads.scm  |    8 ++++----
 tests/monads.scm |    4 +++-
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/guix/monads.scm b/guix/monads.scm
index 61cd533..0b0ad23 100644
--- a/guix/monads.scm
+++ b/guix/monads.scm
@@ -239,10 +239,10 @@ CONDITION is true, return *unspecified* in the current 
monad."
             (identifier? #'id)
             ;; Slow path: Return a closure-returning procedure (we don't
             ;; guarantee (eq? LIFTN LIFTN), but that's fine.)
-            (lambda (liftn proc monad)
-              (lambda (args ...)
-                (with-monad monad
-                  (return (proc args ...))))))))))))
+            #'(lambda (proc monad)
+                (lambda (args ...)
+                  (with-monad monad
+                    (return (proc args ...))))))))))))
 
 (define-lift lift0 ())
 (define-lift lift1 (a))
diff --git a/tests/monads.scm b/tests/monads.scm
index d3ef065..62a07a2 100644
--- a/tests/monads.scm
+++ b/tests/monads.scm
@@ -95,10 +95,12 @@
 
 (test-assert "lift"
   (every (lambda (monad run)
-           (let ((f (lift1 1+ monad)))
+           (let ((f (lift1 1+ monad))
+                 (g (apply lift1 1+ (list monad))))
              (with-monad monad
                (let ((number (random 777)))
                  (= (run (>>= (return number) f))
+                    (run (>>= (return number) g))
                     (1+ number))))))
          %monads
          %monad-run))