\colorbox does not work inside of \gdef

[rudolf-adamkovic]

I am struggling to define a \highlight macro.

\colorbox works:

\colorbox{#FFE270}{Hi.}

\gdef works:

\gdef{\abs}#1{\lvert #1 \rvert}
\abs{5}

\gdef with \colorbox does not work:

\gdef{\highlight}#1{\colorbox{#FFE270}{#1}}
\highlight{Hi.}

All three macros (KaTeX in iA Writer) render as follows:

<img width="443" alt="Screen Shot 2020-10-03 at 00 23 35" src="https://user-images.githubusercontent.com/1158274/94974366-afad8e00-050e-11eb-971b-08be5206e536.png”>

Am I doing something wrong? Is this supposed to work?

[edemaine]

In TeX, a literal # inside a macro needs to be escaped as ##. Try this:

\gdef{\highlight}#1{\colorbox{##FFE270}{#1}}
\highlight{Hi.}

[rudolf-adamkovic]

That worked. Thank you so much!