Auto-generating \mathcal, \mathsf, and \mathbb commands in the LaTeX preamble

June 30, 2026

When writing in LaTeX, I have gotten into the habit of using \Acal as short for \mathcal{A}, \Bcal as short for \mathcal{B}, etc., and similarly for \mathsf{}.

It can be tedious to write out \newcommand{\Xcal}{\mathcal{X}} for each letter and then copy this from project to project. Instead, one can place the following in their preamble:

%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%% All the \mathcals %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%
\def\ddefloop#1{
  \ifx
    \ddefloop#1
  \else\ddef{#1}
    \expandafter
    \ddefloop
  \fi}
\def\ddef#1{\expandafter\def\csname #1cal\endcsname{\ensuremath{\mathcal{#1}}}}

\ddefloop
ABCDEFGHIJKLMNOPQRSTUVWXYZ
\ddefloop

To obtain the same for \mathsf{X}, one need only replace #1cal with #1sf and \mathcal{#1} with \mathsf{#1}. Similarly, I tend to use \RR in place of \mathbb{R}, \NN in place of \mathbb{N}, and so on. The analogous command would look something like the following.

%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%% All the \mathbbs %%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%
\def\ddefloop#1{
  \ifx
    \ddefloop#1
  \else\ddef{#1}
    \expandafter
    \ddefloop
  \fi}
\def\ddef#1{\expandafter\def\csname #1#1\endcsname{\ensuremath{\mathbb{#1}}}}

\ddefloop
ABCDEFGHIJKLMNOPQRSTUVWXYZ
\ddefloop