Use cleveref (or other alternatives) with a custom theorem environment to reference

Question

In this post Custom theorem numbering there is an explanation by egreg that shows how to implement this. Now I would like to be able to reference so that I would not have to type lemma/proposition etc. right before \ref{} when referring to a particular \label{} because by using \ref{} it only gives the numbering. However, using the cref{} from the cleveref package only gives question marks on the page after compilation (which I'm not surprised about since it's a package independent of the code given by egreg). How does one solve this problem?

\documentclass[11pt]{article}

\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsthm}
%\usepackage{xparse}
\usepackage{mathtools}
\usepackage{ulem}
\usepackage{enumerate}
\usepackage{xcolor}

\usepackage[shortlabels]{enumitem} 
\usepackage{cleveref} 

%===========================================================%
%The code below customises theorem numbering
%===========================================================%
\newtheorem{innercustomgeneric}{\customgenericname}  
\providecommand{\customgenericname}{}
\newcommand{\newcustomtheorem}[2]{%
  \newenvironment{#1}[1]
  {%
   \renewcommand\customgenericname{#2}%
   \renewcommand\theinnercustomgeneric{##1}%
   \innercustomgeneric
  }
  {\endinnercustomgeneric}
}


\newcustomtheorem{customdefinition}{Definition}
\newcustomtheorem{customlemma}{Lemma}
\newcustomtheorem{customproposition}{Proposition}
%===========================================================%

\begin{document}

\begin{customproposition}{5.2} \label{hello}
blah blah 
\end{customproposition}

I want to Proposition \ref{hello} without 
having to type proposition 
at the beginning of \ref{hello}.



\end{document}

Is there an efficient and clean way to do this? Either via cleveref or other alternatives by writing a particular code to reference \label{} without having to write "Proposition" in front of the reference?

Answer 1

Add the cleveref type and alias the counter.

\documentclass[11pt]{article}

\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsthm}
%\usepackage{xparse}
\usepackage{mathtools}
\usepackage{ulem}
\usepackage{enumerate}
\usepackage{xcolor}

\usepackage[shortlabels]{enumitem} 
\usepackage{cleveref} 

%===========================================================%
%The code below customises theorem numbering
%===========================================================%
\newtheorem{innercustomgeneric}{\customgenericname}  
\providecommand{\customgenericname}{}
\newcommand{\newcustomtheorem}[2]{%
  \crefname{#2}{#2}{#2s}%
  \newenvironment{#1}[1]
  {%
   \renewcommand\customgenericname{#2}%
   \crefalias{innercustomgeneric}{#2}%
   \renewcommand\theinnercustomgeneric{##1}%
   \innercustomgeneric
  }
  {\endinnercustomgeneric}
}


\newcustomtheorem{customdefinition}{Definition}
\newcustomtheorem{customlemma}{Lemma}
\newcustomtheorem{customproposition}{Proposition}
%===========================================================%

\begin{document}

\begin{customproposition}{5.2} \label{hello}
blah blah 
\end{customproposition}

\begin{customdefinition}{12.4} \label{helloagain}
blah blah 
\end{customdefinition}

I want \cref{hello} without having to type ``proposition''.

Also \cref{helloagain}.

\end{document}