Sorting a list alphabetically by a Macro output

Question

this is an extended question taken by Alphabetically display the items in itemize

The solution posted by Werner is amazing. But what I need is to sort by a value of a macro. For example \foo{Label} is a function that take Label as argument and give you SortLabel as string.

\foo{Label1} %Will print SortLabel1
\foo{Label2} %Will print SortLabel2    
\foo{Label3} %Will print SortLabel3

\begin{sortedlist}
    \sortitem[\foo{Label1}]{Bar1}
    \sortitem[\foo{Label2}]{Bar2}
    \sortitem[\foo{Label3}]{Bar3}
\end{sortedlist}

Tryed to use \expandafter, but seems that datatool can store only by \foo{Label1} and can't sort for SortLabel1....

To be more specific, the function \foo for me is \glossentryname{} that give me the name of a glossary entry. Maybe this could be the reason that expansion doesn't work. Here's a MnWE

\documentclass{article}
\usepackage{datatool}% http://ctan.org/pkg/datatool
\usepackage{glossaries, glossary-tree}
\makeglossaries

%%%%Sorted Functions%%%%
\newcommand{\sortitem}[1]{%
  \DTLnewrow{list}% Create a new entry
  \def\tmp{\DTLnewdbentry{list}{description}}%
  \expandafter\tmp\expandafter{#1}% Add entry as description
}
\newenvironment{sortedlist}{%
  \DTLifdbexists{list}{\DTLcleardb{list}}{\DTLnewdb{list}}% Create new/discard old list
}{%
  \DTLsort{description}{list}% Sort list
  \begin{itemize}%
    \DTLforeach*{list}{\theDesc=description}{%
      \item \theDesc}% Print each item
  \end{itemize}%
}

%%%The Glossary Part%%%%%
\longnewglossaryentry{MVARglossary}{name=MVAR}{
The Description of glossary (not useful at the moment)
}


\begin{document}

Default:
\begin{itemize}
  \item ISDYNSTP:  Is dynamic time step used ?
  \item ISCDCA:
  \item MVAR
  \item IS2TL
\end{itemize}

\def\foo{ISDYNSTP:  Is dynamic time step used ?}
\def\bar{\glossaryname{MVARglossary}}

\glossentryname{MVARglossary}

\bar

Sorted:
\begin{sortedlist}
  \sortitem{\foo}
  \sortitem{ISCDCA:}
  \sortitem{\bar}
  \sortitem{\glossentryname{MVARglossary}}
  \sortitem{IS2TL}
\end{sortedlist}

\end{document}

suggests?

Answer 1

Here, I modified Werner's solution by editing \sortitem as

\newcommand{\sortitem}[1]{%
  \DTLnewrow{list}% Create a new entry
  \def\tmp{\DTLnewdbentry{list}{description}}%
  \expandafter\tmp\expandafter{#1}% Add entry as description
}

in order to expand the argument being processed. Then, in the MWE, I can pass \foo as an item to be sorted (where \foo is a definition unrelated to glossary entry names).

The next problem was that \glossentryname is not expandable. So I employed the existing \glsentryname macro instead (originally, I had made a limited version of \glossentryname, that is expandable, but Nicola pointed out that also plays with the font). I then created a macro \sortgloss{<label>} that will invoke \sortitem on the expanded gloss-entry-name.

Here is the MWE (EDITED to take Nicola's suggestion at using the existing expandable \glsentryname rather than create a new expandable macro)

\documentclass{article}
\usepackage{glossaries}
\usepackage[T1]{fontenc}

\usepackage{datatool}% http://ctan.org/pkg/datatool
\makeatletter
\newcommand{\sortitem}[1]{%
  \DTLnewrow{list}% Create a new entry
  \def\tmp{\DTLnewdbentry{list}{description}}%
  \expandafter\tmp\expandafter{#1}% Add entry as description
}
\makeatother
\newenvironment{sortedlist}{%
  \DTLifdbexists{list}{\DTLcleardb{list}}{\DTLnewdb{list}}% Create new/discard old list
}{%
  \DTLsort{description}{list}% Sort list
  \begin{itemize}%
    \DTLforeach*{list}{\theDesc=description}{%
      \item \theDesc}% Print each item
  \end{itemize}%
}

\makeatletter
\newcommand\sortgloss[1]{%
  \protected@edef\x@glossname{\glsentryname{#1}}%
  \sortitem{\x@glossname}%
}
\makeatother
\begin{document}

Default:
\begin{itemize}
  \item ISDYNSTP:  Is dynamic time step used ?
  \item ISCDCA:
  \item MVAR
  \item IS2TL
\end{itemize}

\newacronym{MVx}{MVAR}{Many Virgins Act Responsibly}


\def\foo{ISDYNSTP:  Is dynamic time step used ?}

Sorted:
\begin{sortedlist}
  \sortitem{\foo}
  \sortitem{ISCDCA:}
  \sortgloss{MVx}
  \sortitem{IS2TL}
\end{sortedlist}


\end{document}

The output is the same as Werner's:

Alternately, if one were to define \sortitem to fully expand its argument:

\makeatletter
\newcommand{\sortitem}[1]{%
  \DTLnewrow{list}% Create a new entry
  \protected@edef\tmpA{#1}%
  \def\tmp{\DTLnewdbentry{list}{description}}%
  \expandafter\tmp\expandafter{\tmpA}% Add entry as description
}
\makeatother

then one would be free to invoke it as \sortitem{\glsentryname{MVx}} rather than \sortgloss{MVx}, if consistency of invocation syntax were important.