I've decided that I must become more adept at TeX if I'm to become proficient with LaTeX. While this is probably obvious to most readers who pass by, my ability to muddle through has hidden this small but important truth. As an example, consider:
% \doublebox
\def\doublebox{\VerbBox\@doublebox}
\def\@doublebox#1{%
\begingroup
\setbox\@fancybox\hbox{{#1}}%
\fboxrule=.75\fboxrule
\setbox\@fancybox\hbox{\fbox{\box\@fancybox}}%
\fboxrule=2\fboxrule
\fboxsep=\fboxrule
\advance\fboxsep .5pt
\fbox{\box\@fancybox}%
\endgroup}
This is a snippet from fancybox.sty by Timothy Van Zandt. I wish to clone and improve it (at least by my lights) by adding control over inner and outer rule width, likewise separation as well. To this small wish list I want to add color on a per rule basis. So what's the problem you say? The problem is that I don't understand the above well enough to modify it. In a nutshell, I don't see a way to add parameters to \doublebox in a way that gets through to \@doublebox. For that matter I'm not really sure I understand the calling sequence. As an example consider my title page that I use as a test bed:
\documentclass{article}
\usepackage{modfancybox}
\usepackage{nth}
\begin{document}
\newlength{\fb}
\setlength{\fb}{5.625ex}
\addtolength{\fb}{1pt}
\newlength{\myl}
\setlength{\myl}{\textwidth}
\addtolength{\myl}{-\fb}
\thispagestyle{empty}
\thisfancypage{%
\setlength{\fboxrule}{.75ex}
\setlength{\fboxsep}{10pt}
\doublebox
}{}
\parbox{\myl}{%
\null\vfil
\vskip 60pt
\centering
{\huge A HISTORY OF\\
THE\\
MYERS\\
OVERSTREET\\
and\\
GRAY\\
FAMILIES\\}
\vskip 2em
{\large
\lineskip .75em
\textit{\nth{1} Edition By}: Jourdan George Myers \par
\textit{\nth{2} Edition Edited By}: Hugh Shannon Myers \par
\vskip 1.5em}
{\large 1st. Edition \\December 27, 1983 \\2nd. Edition \\\today \par}
{\small vrs.\input{version}$\alpha$}
\vskip 1in
``It is not Abraham -- It is Abram''
}
\end{document}
The heart of all of this seems to be:
\thisfancypage{%
\setlength{\fboxrule}{.75ex}
\setlength{\fboxsep}{10pt}
\doublebox
}{}
Which somehow seems to pull in the \parbox that follows. Given the setup of \thisfancypage, this certainly makes sense. It also makes it rational to hard-wire the 3 values I want better control over :) That said, I still want my cake and to eat it as well. Adding color seems to be the least of my concerns as there are a number of ways to handle that. And now that I think about it, I could also create the various new lengths to add the control that I want. But that isn't really a solution that works in the long term. I can only get that by increasing my knowledge.
So TLTR: How to a create a parametric version of \doublebox? And what is happening in \thisfancypage? My hope is to be able to get far enough to not only create a newer \doubleboxP but even perhaps a \Nbox as well. For those who dislike such things as somehow violating current typographic standards I apologize, but my likes relate more to the 19th century than to the 21st century :)
\def\doublebox{\VerbBox\@doublebox},\VerbBoxgets\@doubleboxas argument as a macro to execute after it has boxed the content. You should be able to simply write e.g.\def\doublebox#1{\VerbBox{\@doublebox{#1}}}or\newcommand\doublebox[1][]{\VerbBox{\@doublebox{#1}}}. However, the look-ahead code for optional arguments will fix the catcode of the first character which follows, which might be an issue. – Martin Scharrer♦ Jan 26 at 8:37