How can I define a key-value command like \hypersetup?

Question

I am quite familiar with switch (\if...\else...\fi) now and read many questions on key-value topic, but I cannot find an example to create the options listing command like \hypersetup, to make

\documentclass[key1=...,key2=...,key3=...]{myclass}

equivalent to

\documentclass{myclass}
\myclssetup{%
    key1 = ...,
    key2 = ...,
    key3 = ...,
    .............
}

None of these keys are boolean, and all these values helps me to do switch into different layout schemes. For instance, key1 is to set one type of cover page and key2 is to set one type of section formats. I do not need to draw something or to set some geometry properties (I don't need values of numerical parameters). I also want some default options pre-set, if the user didn't specify their options.

If I use the kvoptions package, all I know is that I probably need \newif and \DeclareVoidOption (kvoptions package) to create options (values), \define@key (keyval package) and \kvsetkeys command (keyval package) to link values and keys. However, I have been struggling to find similar and simple examples to achieve the function I need.

I think it's important to stress that I am writing a class (not package), and it will be based on another class (like book).

Answer 1

Here's a xkeyval version, with automatic definition of keys and it's keyval macro and a corresponding \if... whether the option is used.

The precise implementation depends on the internal options to be specified what they should do if specified. I assumed, that the class options are to be stored to a macro, say \classoption@myclass@#2 where #2 has the relevant meaning, say paper or width etc.

\documentclass{article}


\usepackage{xkeyval}

\makeatletter

\newcommand{\definemykey}[2]{%
  \expandafter\newif\csname ifmyclassname@#1\endcsname
  \define@key{myclass}{#1}{%
    \expandafter\gdef\csname classoption@myclass@#2\endcsname{##1}
    \global\expandafter\csname myclassname@#1true\endcsname
  }
}

\definemykey{keyA}{KeyA}
\definemykey{keyB}{KeyB}
\definemykey{keyC}{KeyC}


\newcommand{\myclasssetup}[1]{%
  \setkeys{myclass}{#1}%
}

\makeatother


\myclasssetup{keyB={upvote good answers!}, keyC={provide a MWE}}

\begin{document}

\makeatletter
\ifmyclassname@keyA
Yes, it was specified
\else
No, it is missing
\fi


\ifmyclassname@keyB
Yes, it was specified and has the value \textbf{\classoption@myclass@KeyB}
\else
No, it is missing
\fi

\makeatother


\end{document}

Answer 2

Examples for kvoptions among my packages: accsupp, attachfile2, bookmark, enparen, epstopdf-base, grffile, pagegrid, pmboxdraw, rerunfilecheck, resizegather, selinput, zref-xr, ...

A grep -r kvoptions TDS:tex/latex will reveal much more packages.

Example rerunfilecheck:

% Package start
[...]
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{rerunfilecheck}%
  [2011/04/15 v1.7 Rerun checks for auxiliary files (HO)]

% Option setup
\RequirePackage{kvoptions}[2010/02/22]
\SetupKeyvalOptions{%
  family=rerunfilecheck,%
  prefix=ReFiCh@%
}

% The setup command (a convenience wrapper for `\setkeys`:
\newcommand*{\RerunFileCheckSetup}{%
  \setkeys{rerunfilecheck}%
}

% The options
\DeclareBoolOption{mainaux}
\DeclareBoolOption{partaux}
\DeclareBoolOption{starttoc}
\DeclareBoolOption{index}
\DeclareBoolOption{glossary}
\define@key{rerunfilecheck}{aux}[true]{%
  \RerunFileCheckSetup{%
    mainaux={#1},%
    partaux={#1},%
    starttoc={#1},%
    index={#1},%
    glossary={#1}%
  }%
}

% Option processing: first configuration file, then package options
\InputIfFileExists{rerunfilecheck.cfg}{}{}
\ProcessLocalKeyvalOptions*

% Helper macro to disable options
\def\ReFiCh@DisableOption{%
  \DisableKeyvalOption[%
    action=warning,%
    package=rerunfilecheck%
  ]{rerunfilecheck}%
}

[...]

% The options are disabled after they have been used the last time:
\ReFiCh@DisableOption{mainaux}
\ReFiCh@DisableOption{partaux}
\ReFiCh@DisableOption{starttoc}
\ReFiCh@DisableOption{index}
\ReFiCh@DisableOption{glossary}
\ReFiCh@DisableOption{aux}

[...]