[Tex/LaTex] \ref and \nameref with alpha enumerated items

cross-referencingenumitem

Is there a way to keep the enumeration list with (a), (b), etc., and have references provide the complete context like 1.1.1(a)?

enter image description here

The section and sub-section references display as I’d like with 1.1 and 1.1.1 and the name-references works as well, “First” and “And..”. The enumerated item reference shows as 28 but I'd like 1.1.1(ab). And the enumerated item name-reference is wrong (“Also..”), though perhaps that’s intentional. So, the enumerated alpha item reference has two issues: it doesn’t include it’s context; and, it doesn’t honor the enumeration alpha display characteristics.
For my use, a custom command for the references is fine but the command hopefully won't require both the subsection and the item labels, e.g., instead of writing the verbose and error-prone:

\myuglyitemref{subsec:first-and}{itm:faab}

is there some way to define a reference so I can write:

\myawesomeitemref{itm:faab}

which displays 1.1.1(ab)?

\documentclass{report}
\usepackage{alphalph}
\usepackage{enumitem}
\usepackage{nameref}
\makeatletter
\def\enumalphalphcnt#1{\expandafter\@enumalphalphcnt\csname c@#1\endcsname}
\def\@enumalphalphcnt#1{\alphalph{#1}}
\makeatother
\AddEnumerateCounter{\enumalphalphcnt}{\@enumalphalphcnt}{aa}
\renewcommand{\labelenumi}{(\enumalphalphcnt{enumi})}
% my (ugly) item reference
\newcommand{\myuglyitemref}[2]{\ref{#1}\labelenumi}
\begin{document}
\chapter{SOMETHING}The chapter.
\section{First}\label{sec:first}
Section items show with (ab) but referenced with 1.1(ab)
\begin{enumerate}\setcounter{enumi}{27}
\item {First 28} \label{itm:fab} 28th element
\end{enumerate}
\subsection{And...}\label{subsec:first-and}
Subsection items show with (a) but referenced with 1.1.1(a)
\begin{enumerate}\setcounter{enumi}{27}
\item {And 28} \label{itm:faab} 28th element
\end{enumerate}
Correct: \ref{sec:first} and \ref{subsec:first-and}
Correct: ``\nameref{sec:first}'' and ``\nameref{subsec:first-and}''
Incorrect: \ref{itm:fab} and \ref{itm:faab} - should be 1.1(ab) and 1.1.1(ab)
Incorrect: ``\nameref{itm:faab}''
Ugly: \myuglyitemref{subsec:first-and}{itm:faab}

Best Answer

My answer addresses only the cross-referencing of enumerated items, where the appearance of the cross-referenced "numbers" depends on whether the items occur at the section level or the subsection level. (Aside: This site "works" best if postings contain only one major question at a time. That's why I'm not even trying to address the other major question you've raised, viz., how to use \nameref on the "titles" of enumerated items.)

The solution works by modifying the low-level LaTeX macros \theenumi, \labelenumi, and \p@enumi. Observe the use of an \ifnum conditional in the statement that modifies the \p@enumi macro.

In the example below, the hyperref package is loaded merley to highlight which parts of the typeset text are the actual cross-references generated by \ref instructions.

enter image description here

\documentclass{report}
\usepackage{alphalph}

\renewcommand\theenumi{(\alphalph{\value{enumi}})}
\renewcommand\labelenumi{\theenumi}
\makeatletter
\renewcommand\p@enumi{\ifnum\value{subsection}=0{\thesection}\else{\thesubsection}\fi}
\makeatother

\usepackage[colorlinks]{hyperref} %% just for this example

\begin{document}
\chapter{SOMETHING}
The chapter.

\section{First section}\label{sec:first}

Section-level enumerated items: Labels should show as ``(ab)'' and should be cross-referenced as ``1.1(ab)''.

\begin{enumerate}
\setcounter{enumi}{27}
\item 28th element \label{itm:fab} 
\end{enumerate}

\subsection{First subsection}\label{subsec:first-and}
Section-level enumerated items: Labels should show as ``(ba)'' and should be cross-referenced as ``1.1.1(ba)''.

\begin{enumerate}
\setcounter{enumi}{52}
\item 53rd element \label{itm:faab} 
\end{enumerate}

\subsection{Second subsection}

Correct: Section \ref{sec:first} and subsection \ref{subsec:first-and} \dots

\medskip\noindent
Now also correct: Items \ref{itm:fab} and \ref{itm:faab} \dots

\end{document}
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