diff options
Diffstat (limited to 'guix/monads.scm')
| -rw-r--r-- | guix/monads.scm | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/guix/monads.scm b/guix/monads.scm index 2ab3fb94f0..d9580a7f8e 100644 --- a/guix/monads.scm +++ b/guix/monads.scm @@ -38,6 +38,7 @@ with-monad mlet mlet* + mbegin lift1 lift2 lift3 lift4 lift5 lift6 lift7 lift listm foldm @@ -171,6 +172,19 @@ form is (VAR -> VAL), bind VAR to the non-monadic value VAL in the same way as (let ((var temp) ...) body ...))))))) +(define-syntax mbegin + (syntax-rules () + "Bind the given monadic expressions in sequence, returning the result of +the last one." + ((_ monad mexp) + (with-monad monad + mexp)) + ((_ monad mexp rest ...) + (with-monad monad + (>>= mexp + (lambda (unused-value) + (mbegin monad rest ...))))))) + (define-syntax define-lift (syntax-rules () ((_ liftn (args ...)) |