Is the notation for values of a derivative at some point that I used in this question commonly accepted and understandable? Is there a more preferred one?
For those who familiar with Mathematica — I used the notation
to represent an equivalent of Mathematica expression
Derivative[1, 0][BesselJ][1/2, x] or, equivalently,
Function[ν, BesselJ[ν, x]]'[1/2].