With beamer, "Missing { inserted." (regression)

[Vincent Lefevre]

On 2022-02-18 09:05:26 +0000, Joseph Wright wrote:
> On 18/02/2022 03:12, Vincent Lefevre wrote:
> > Even though the behavior was not officially supported, there were
> > no errors without the additional braces and this was simpler and
> > more easily readable, so that it was probably used in practice.
> > I can see that in many of my old .tex files (not all using beamer).
> 
> Lamport's book is entirely clear on the supported syntax for sub- and
> superscripts.

There are other sources that are much less clear, like

  https://en.wikibooks.org/wiki/LaTeX/Mathematics#Powers_and_indices

It currently says that \sfrac needs curly braces:

  $x^{\sfrac{1}{2}}$ % no error

but that using \frac without them is fine:

  $x^\frac{1}{2}$ % no error

I don't think that this is an issue if one has the guarantee that
there will never be a breakage. Otherwise, if this may be like
beamer and \textnormal, curly braces should be recommended.

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Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
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