Re: problem with math: "\left" leads to "udefined symbol" --solved (sort of)

[Hans Hagen <pragma@wxs.nl>]

On 1/24/2017 4:47 PM, j. van den hoff wrote:
> well after incrementally deleting most everything from my document I now
> seem to have a reproducible example:
>
> 8<--------------------------------------------
> \definesynonyms[MySymbol][MySymbols][\meaning]
>    \MySymbol [whaever] {this} {  means }
>
> \starttext
> \startformula
> x = \left ( 1 + 2 \right )
> \stopformula
> \stoptext
> 8<--------------------------------------------
>
> the apparent "culprit" is the presence of the `\definesynonyms' stuff.
> without it the rest (identical to your minimal example) compiles. with
> it it does not... remember that I am really unexperienced with
> `context': at the time (2 years ago), when I first tried this, it
> worked. I now realize (after reading up on the `definesynonyms' syntax
> again ...) that
> in the definition a _command_ has to go into the third bracket.
> seemingly at the time I was just putting a placeholder `\meaning' there
> (never attempting to use it as a command acting on the explanatory text
> for that symbol definition but only wanting a glossary.
>
> the strange thing (for me) is that this worked just fine two years ago,
> now it does produce a very strange error as described. question is why.
>
> but replacing `\meaning' by `\infull' suffices to restore sane behaviour.
>
> while I understand, that I did something stupid (putting a non-existent
> command `\meaning' in the definition), I would have presumed that this
> might trigger an error at that place rather than making `\left ('
> suddenly an undefined control sequence. any explanation what is going on
> here would be greatly appreciated.

\meaning is a primitive ... best use \UpperCase names for such commands 
... imagine that you overload \relax or \hbox or ...

>
>
> On Tue, 24 Jan 2017 15:02:38 +0100, Hans Hagen <pragma@wxs.nl> wrote:
>
>>  this just works here ... so can others confirm it?
>>  \starttext
>>  \startformula
>>     x =  \left ( 1 + 2 \right )
>> \stopformula
>>  \stoptext
>
>


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