Wrap many math macros into `\ensuremath`

Question

I find it more natural refering to \Phi, \alpha, \sim, etc. outside math mode the same as inside math mode. I.e. writing:

Consider \Phi, \alpha{} and \sim{} in the following equation:
\begin{equation}
    \Phi \sim \alpha
\end{equation}

Instead of:

Consider $\Phi$, $\alpha$ and $\sim$ in the following equation:
\begin{equation}
    \Phi \sim \alpha
\end{equation}

My naive approach is to override all the macros I need with their own variant, following this post, with:

\let\NPhi\Phi % native phi
\def\Phi{\ensuremath{\NPhi}}
\let\Nalpha\alpha % native alpha
\def\alpha{\ensuremath{\Nalpha}}
\let\Nsim\sim
\def\sim{\ensuremath{\Nsim}}
..

But it is quite tedious. How could I loop over that? So that:

\magiccommand{
    Phi,
    alpha,
    sim,
    ..}

would produce the same result?

As usual, any time you will shave off with this macro will be spent when you are trying to debug the weird errors you will get because of this. — percusse, Apr 19 '18 at 16:51
Related Question: When not to use \ensuremath for math macro?. — Peter Grill, Apr 19 '18 at 16:56
What is better? \alpha{} (having to remember to add {}) or just $\alpha$ ? I have no doubt it's the latter. — egreg, Apr 19 '18 at 17:19
@PeterGrill related indeed :) Thanks for that. I don't think it's a problem for such macros with no arguments, though, since there will be no semantic to break. — iago-lito, Apr 20 '18 at 07:31
@egreg I understand. To me, it is not a matter of number of chars or semantics, but a matter of consistency (which I feel LaTeX often lacks). (+ for those in the mood for nitpicking, number of chars wins in the occasional case of \Phi, because of the comma :P) — iago-lito, Apr 20 '18 at 07:34
@iago-lito To the contrary, $\alpha$ is consistent, because \alpha is a math symbol. — egreg, Apr 20 '18 at 08:07
@egreg I agree. My point is that it is consistent within a context with much semantics; i.e. a context where I have to make a distinction between "maths symbols" and "non-maths symbols" (this is why I wrote about "semantics"). As a user, all I want is a \Phi and there is no such math/nomath semantic distinction in my brain. Thus, in my (restrained, semantically-weaker) context, I find \Phi{} more consistent :) — iago-lito, Apr 20 '18 at 08:49
@egreg At the other end of this interesting "semantics vs. consistence" tradeoff, we could also -distinguish- :every: :word: :like: :this: -depending- :on: :whether: :they: -are- :a: :verb: :or: :not:, which would be consistent in a grammar-caring context, and unconsistent in a more relaxed context where all we want is just typing words, what do you think? ^ ^ — iago-lito, Apr 20 '18 at 08:53

Heiko Oberdiek · Accepted Answer · 2018-04-19T16:59:23.140

All you need is a parser for comma separated values. The following example uses \comma@parse of package kvsetkeys. The macro automatically strips spaces at the begin and end of the values.

\documentclass{article}
\usepackage{kvsetkeys}
\makeatletter
\newcommand*{\EnsureMathDef}[1]{%
  % Throw error, if "\N#1" is already defined.
  \expandafter\@ifdefinable\csname N#1\endcsname{%
    % Save old meaning
    \expandafter
    \let\csname N#1\expandafter\endcsname
    \csname #1\endcsname
    % Define new macro
    \expandafter\edef\csname #1\endcsname{%
      \noexpand\ensuremath{%
        \expandafter\noexpand\csname N#1\endcsname
      }%
    }%
  }%
}
\comma@parse{
  Phi,
  alpha,
  sim,
}\EnsureMathDef
\makeatother

\begin{document}
Consider \Phi, \alpha{} and \sim{} in the following equation:
\begin{equation}
    \Phi \sim \alpha
\end{equation}
\end{document}

Without additional package

The macro kernel provides \@for. Line ends must be commented to avoid additional spaces.

\documentclass{article}
\makeatletter
\@for\x:=%
  Phi,%
  alpha,%
  sim%
\do{%
  % Throw error if macro with prefix N is already defined.
  \expandafter\@ifdefinable\csname N\x\endcsname{%
    % Save old meaning
    \expandafter
    \let\csname N\x\expandafter\endcsname
    \csname\x\endcsname
    % Define new macro
    \expandafter\edef\csname\x\endcsname{%
      \noexpand\ensuremath{%
        \expandafter\noexpand\csname N\x\endcsname
      }%
    }%
  }%
}
\makeatother

\begin{document}
Consider \Phi, \alpha{} and \sim{} in the following equation:
\begin{equation}
    \Phi \sim \alpha
\end{equation}
\end{document}

This does work! I like the version with \@for with no additional package, since I don't mind much about trailing %. Thanks a lot :) — iago-lito, Apr 20 '18 at 07:39

Wrap many math macros into `\ensuremath`

1 Answers1

Without additional package

Linked