how to bind input argument to function

[razetime]

I am trying to convert a ruby lambda to equivalent J-uby here: Try it online!

my problem is at :% & :& where i'm trying to derive f.(x) = :% & x. I'm not sure how to perform that.

[razetime]

as a side note, :* & (~:*) does not work in place of :* & (~:**&2).