Extracting the name of a function (inverse of match.fun("myFun"))

deparse(substitute(fnc)) will get you part way there.

I like to let the user override what substitute might say by
making a new argument out of it:

applyFunc(function(x)x*10, 1:3)

fnc is function(x) x * 10
[1] 10 20 30

applyFunc(function(x)x*10, 1:3, fncString="Times 10")

fnc is Times 10
[1] 10 20 30
This makes is easier to call your function from another one - you
can pass the fncString down through a chain of calls.