[Dev-luatex] Behaviour of \textdir in alignment preambles (Re: \pardir and \textdir etc)

[Taco Hoekwater]

Eythan Weg wrote:
> 
> This snippet still crushes in either dvi or pdf mode:
> 
> \pardir TRT \textdir TRT 
> This is some text
> \textdir TLT 
> and this is too.

The current trunk 'fixes' this crash by simply guarding the statement
that triggered the crash. I am not 100% sure that the program behaviour
is algorithmically correct now, but the pdf output does look ok, so I
will leave it at that (the dvi has overprint again, but with aleph the
result dvi is totally invalid, so I guess I have made progress).

Best wishes,
Taco