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monads: Fix 'liftN' fallback case.

Reported by Andy Wingo <wingo@igalia.com>.

* guix/monads.scm (define-lift) <fallback case>: Add missing #'.  Remove
  extra formal parameter.
* tests/monads.scm ("lift"): Add test with 'lift1' as a procedure.
wip-container
Ludovic Courtès 7 years ago
parent
commit
dbbc248aee
  1. 8
      guix/monads.scm
  2. 4
      tests/monads.scm

8
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))

4
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))

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