How to 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}

Answer 2

Like this? Defined a new command \pref, which "prints" "Proposition" and the \ref .

Remarks: also works when you use labels like this environment:label (like fig:drawing), which is useful once you've got many different types of environments.

\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}
%~~~ new ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~% <<==
\newcommand{\pref}[1]{Proposition \ref{#1}}
%===========================================================%
\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}. \
Is this the way you want to make a call to \pref{hello}?% <<==
\end{document}

Result: