The package cleveref has two types of references, \cref for lowercase and \Cref for uppercase. Does the package provide a way to define more types? If not, how may you define one yourself?
As an example, one may want to define abbreviated versions of the references, such that the code:
\documentclass{article}
\usepackage{fontspec, amsthm, hyperref}
\usepackage[nameinlink]{cleveref}
\newtheorem{theorem}{Theorem}
% Defining \abbrcref
% Defining \abbrCref
% Defining \abbrcrefformat
% Defining \abbrCrefformat
\crefformat{theorem}{#2theorem #1#3}
\Crefformat{theorem}{#2Theorem #1#3}
\abbrcrefformat{theorem}{#2th.#1#3}
\abbrCrefformat{theorem}{#2Th.#1#3}
\begin{document}
\begin{theorem}
\label{sometheorem}
\end{theorem}
\cref{sometheorem}, \Cref{sometheorem}, \abbrcref{sometheorem}, \abbrCref{sometheorem}
\end{document}
Would produce:
How would one go about doing that?

