Add lines (NOT a box) above and below text (similar to verbatim) in a non-verbatim format

Question

This is a follow-on question to a previous question on SE where it was suggested I create a new question.

Question: How to add lines (NOT a box) above and below non-verbatim text while maintaining access to ALL the traditional LaTeX text attributes including but not limited to fontfamily, fontshape (including italics, bolding, etc.), text color, etc.

This would include the ability to control the attributes of the lines above and below (together or separately) including but not limited to the line thickness, separation (above and/or below, together or separately) of the lines from the text, the color(s) of the lines (together or separately, single or progressive), and the fill color(s) (single or progressive) between the lines.

The numerous SE questions and answers I've reviewed do NOT meet the criteria I am looking for.

I've been able to meet a few of the above requirements using a combination of verbatim and fancyvrb in the following MWE:

\documentclass[varwidth]{article}
\usepackage{fancyvrb}
\usepackage{varwidth}
\usepackage{verbatim}
\usepackage{xcolor}
\begin{document}
{\centering
\begin{varwidth}{0.33\linewidth}
\begin{Verbatim}[commandchars=\{}, fontfamily=courier, fontshape=it, numbers=none, frame=lines, framerule=0.7mm, framesep=3mm, rulecolor=\color{red}, fillcolor=\color{yellow}]
\textbf{Source} \textrightarrow \textbf{Migration}
\end{Verbatim}
\end{varwidth}
\par}
\end{document}

which results in:

However, if I try to substitute $\rightsquigarrow$ for \textrightarrow, I get the following LaTeX error:

Undefined control sequence.
<argument> Source $\rightsquigarrow 
                                    $ Migration
l.12 Source $\rightsquigarrow$ Migration

So for some reason, my attempt to insert the equivalent of an Inline Equation results in an error.

Also, my attempt to fill in the space between the two lines (e.g. fillcolor=\color{yellow}) fails when employing the above verbatim and fancyvrb code.

As outlined in the previous question on SE, I am attempting to reproduce the image that appeared in Dr. Thomas F. Sturm's sanitize-umlaut package for verbatim text:

but for straightforward, run-of-the-mill, non-verbatim text (e.g. \textbf{}, $<equation>$, etc.).

I'm looking for a way to present text in the format (displayed above) in Sturm's documentation without the limitations I've encountered when using verbatim based code.

(Special thanks to egreg and Marcel Krüger for their assistance!)

Thanks for reading.

Answer 1

Try this

\documentclass[varwidth]{article}
\usepackage{fancyvrb}
\usepackage{amssymb}
\usepackage{varwidth}
\usepackage{verbatim}
\usepackage{xcolor}
\begin{document}
{\centering
\begin{varwidth}{0.33\linewidth}
\begin{Verbatim}[commandchars=\{}, codes={\catcode`$=3},fontfamily=courier, fontshape=it, numbers=none, frame=lines, framerule=0.7mm, framesep=3mm, rulecolor=\color{red}, fillcolor=\color{yellow}]
\textbf{Source} $\rightsquigarrow$ \textbf{Migration}
\end{Verbatim}
\end{varwidth}
\par}
\end{document}

I made two changes, first is that I loaded \usepackage{amssymb} which provided the \rightsquigarrow symbol. Second is that I enabled math mode with the codes={\catcode`$=3} invocation, as explained in the fancyvrb documentation (section 4.1.17 on Catcode characters):

---

Actually, reading your question again: if you don't want to use verbatim, why use fancyvrb at all? If you just want to draw a box with some lines and colors, use something like mdframed instead. E.g. (I did my best to reproduce the settings you listed for the frames.)

\documentclass[varwidth]{article}
\usepackage{xcolor}
\usepackage{mdframed}
\usepackage{amssymb}
\usepackage{varwidth}
\begin{document}
{\centering
\begin{varwidth}{0.33\linewidth}
        \begin{mdframed}[skipabove=3mm,skipbelow=3mm,linecolor=red,backgroundcolor=yellow,linewidth=0.7mm,leftline=false,rightline=false]
                \textbf{A} $\rightsquigarrow$ \textsc{b}
        \end{mdframed}
\end{varwidth}
\par}
\end{document}

which produces

---

Looking at your previous question and the linked reference file, it seems that you want to use it to create an in-line highlighting effect? In that case you should use tcolorbox instead.

\documentclass{article}
\usepackage{amssymb}
\usepackage[skins]{tcolorbox}
\newtcbox{\myhl}{nobeforeafter,tcbox raise base,toprule=2pt, bottomrule=2pt, leftrule=0pt, rightrule=0pt, top=1mm,bottom=1mm,
  right=1pt,left=1pt,arc=0pt,boxsep=0pt,
  colframe=red,colback=yellow!10!white}
\MakeRobust\myhl
\begin{document}
Some text before \myhl{\textbf{A} $\rightsquigarrow$ \textsc{b}} some text after
\end{document}

Which gives

Update from OP: Latest image of what I was looking for from the beginning:

Perfect! Thank you Willie Wong!!