03/06: monads: Add 'lift0'.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit b307c06456eefa10ebe59216599f554dae641cd6
Author: Ludovic Courtès <address@hidden>
Date:   Tue Dec 2 10:10:51 2014 +0100

    monads: Add 'lift0'.
    
    * guix/monads.scm (lift0): New variable.
---
 guix/monads.scm |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/guix/monads.scm b/guix/monads.scm
index 52cb3f5..65683e6 100644
--- a/guix/monads.scm
+++ b/guix/monads.scm
@@ -41,7 +41,7 @@
             mbegin
             mwhen
             munless
-            lift1 lift2 lift3 lift4 lift5 lift6 lift7 lift
+            lift0 lift1 lift2 lift3 lift4 lift5 lift6 lift7 lift
             listm
             foldm
             mapm
@@ -222,6 +222,7 @@ CONDITION is true, return *unspecified* in the current 
monad."
          (with-monad monad
            (return (proc args ...))))))))
 
+(define-lift lift0 ())
 (define-lift lift1 (a))
 (define-lift lift2 (a b))
 (define-lift lift3 (a b c))