[NTG-context] \placeformula and $$ doesn't work anymore

[Taco Hoekwater]

Aditya Mahajan wrote:
> 
> This is a bug in doplaceformula. I do not know how to avoid it, but 
> the next code illustrates what is happening.
> 
> \def\dotest{
>    \def\nextnext{$}%
>    \ifx\next\nextnext
>      Inside dispplaceformula\ldots % This always fails
>    \else
>      Inside dodoplaceformula\ldots
>   \fi}
> 
> \def\test{\futurelet\next\dotest}
> 
> \test$$A = B$$
> 
> This prints "Inside dodoplaceformula" even though the next character 
> is \$.
> 
> So, the \next=\nextnext branch never matches. I do not know why this 
> happens, but a more robust check is needed in doplaceformula.

One is a macro, the other a \let character.  This would work:

   \def\dotest{
      \let\nextnext=$
      \ifx\next\nextnext
        Inside dispplaceformula\ldots % This always fails
      \else
        Inside dodoplaceformula\ldots
     \fi}

but the \ifcat is file as well, I think

Taco