Vtyjkyuk

I was trying to redefine texttt command to make it have background color using package soul. But it seems that it is harder than I thought.

My initial code is

documentclassarticle
usepackagexcolor, soul
colorletmycolorred!30
sethlcolormycolor

letoldtexttttexttt
renewcommandtexttt[1]
 hloldtexttt#1


begindocument

textttcan we highlight

enddocument

But it won't run, the error message is:

Argument of texttt has an extra }.

I searched and found this post. The post suggests to use soulregister command. So I add the following line before begindocument:

soulregistertexttt1

But the error persists. I also found this post, which further suggests to use DeclareRobustCommand. Now my code is

documentclassarticle
usepackagexcolor, soul
colorletmycolorred!30
sethlcolormycolor

letoldtexttttexttt
% renewcommandtexttt[1]
% hloldtexttt#1
% 

DeclareRobustCommandtexttt[1]
 hloldtexttt#1

soulregistertexttt1

begindocument

textttcan we highlight

enddocument

But it doesn't work. The error message is

TeX capacity exceeded, sorry [grouping levels=255]

It seems like rabbit hole of issues. Can you point out what has gone wrong? How to fix this seemingly simple problem?

Edit:

I am using Pandoc to convert Markdown file to PDF. The underlying LaTeX command for Markdown inline code is texttt. But there is no background color. That is why I want to combine soul and texttt.

I have tried the solution of @egreg and @daleif. They both work for standard alone tex code.

documentclassarticle
usepackagexcolor, soul

colorletmycolorred!30
sethlcolormycolor

letoldtexttttexttt

% renewcommandtexttt[1]
% ttfamilyhl#1
% 

DeclareRobustCommandtexttt[1]%
 hlttfamily#1%


begindocument

textttcan we highlight

enddocument

But if I put it in a file head.tex and compile Markdown to PDF, there are still errors. The content of head.tex is:

usepackagexcolor, soul

colorletmycolorred!30
sethlcolormycolor

letoldtexttttexttt
DeclareRobustCommandtexttt[1]%
 hlttfamily#1%

Content of test.md is

`some inline words`

If I try to generate PDF using the new header:

pandoc -H head.tex -s test.md -o test.pdf

there occurs another error:

Package soul Error: Reconstruction failed.

The soul macros are rather special, it works on a macro level this cannot handle that the contents has "macros" in it.

I would not overload texttt like that, make a special macro for it.

BTW: This works ttfamilyhl#1

The working of texttt is essentially absorbing its argument and issuing ttfamily.

documentclassarticle
usepackagexcolor, soul

colorletmycolorred!30
sethlcolormycolor

DeclareRobustCommandtexttt[1]%
 hlttfamily#1%


begindocument

textttcan we highlight

enddocument

On the other hand, it would be better to use a different command:

documentclassarticle
usepackagexcolor, soul

colorletmycolorred!30
sethlcolormycolor

DeclareRobustCommandhltt[1]%
 hlttfamily#1%


begindocument

hlttcan we highlight

enddocument

Don't forget to protect the end-of-lines.