[PATCH] Add Method#curry
There is already Proc#curry, but to curry a method you need to go through to_proc. This patch adds
Method#curry which delegates to
Looking forward to seeing this discussed.
Updated by plexus (Arne Brasseur) almost 6 years ago
- File 0001-Implement-Method-curry-which-delegates-to-to_proc.cu.patch 0001-Implement-Method-curry-which-delegates-to-to_proc.cu.patch added
Updated the patch with documentation. There's an interesting side effect to be considered.
Method#to_proc returns a lambda that checks its arity.
Proc#curry takes an optional
arity argument. If this doesn't match the method's arity then the result can not be called.
def two_args(a,b) end curried = method(:two_args).to_proc.curry(1) curried.(1) # -:4:in `curry': wrong number of arguments (1 for 2) (ArgumentError) # from -:4:in `<main>' curried.(1, 2) # -:4:in `curry': wrong number of arguments (1 for 2) (ArgumentError) # from -:4:in `<main>' curried.(1, 2, 3) # -:4:in `curry': wrong number of arguments (1 for 2) (ArgumentError) # from -:4:in `<main>'
In the case of a method with variable arguments the arity argument is important though, because otherwise the currying has no effect.
def varargs(*args) args end curried = method(:varargs).to_proc.curry curried.(1) # =>  curried.(1,2) # => [1, 2] curried = method(:varargs).to_proc.curry(3) curried.(1) # => #<Proc:0x007f0cb8fc6fe0 (lambda)> curried.(1).(2).(3) # => [1, 2, 3]
I think it would make sense for a
Method#curry method to raise an error or at least give a warning when passing the wrong arity to a fixed-arity function.
Updated by nobu (Nobuyoshi Nakada) almost 6 years ago
- Status changed from Open to Closed
- % Done changed from 0 to 100
Applied in changeset r46461.
proc.c: Implement Method#curry
- proc.c (rb_method_curry): Implement Method#curry, which delegates to to_proc.curry. [ruby-core:62212] [Feature #9783]