# [luatex] \mathchardef\foo=\mathcode`\x

Hans Hagen pragma at wxs.nl
Fri Dec 18 23:30:16 CET 2015

```On 12/18/2015 11:24 PM, David Carlisle wrote:
>> changing the meaning of \mathchardef is also kind of incompatible (who knows who depends on the error message for whatever reason)
>
> changing anything in tex is incompatible with something, as we both know:-)
>
>> anyway, i'll add that fallback but there is no way back and it will not be under some 'option' control
>
> options wouldn't be good, I agree. Just lead to incompatible setups
> and confusion.
>
> as I said in the last message not necessarily flagging for exactly
> that change (I've not had long to think about it really, I'm just
> working down our test failures and analysing the results) but wanted
> to flag the issue and post the macro workaround, so that it could be
> discussed (or at least known about:-)

let's add it and later we can decide to remove it (back to the error) so
that there is time to adapt ...

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