[tex-eplain] \sidx not catcode-clean

[Oleg Katsitadze]

On Sun, Apr 23, 2006 at 10:56:11AM -0400, Dorai Sitaram wrote:
> \uncatcodespecials
> \catcode`\{=1
> \catcode`\}=2
> \catcode`\ =10
> % and other exceptions 

I guess we need these other exceptions:

  \catcode`\^^I=10
  \catcode`\^^M=5

to make sure the parameter is not affected by current
definitions of tabs and newlines.

> Preserving the severalness of verbatim spaces in the index serves no
> legible purpose I can think of.

OK, I agree.  Even though incompatibilities would still be
possible, the constructs are so exotic that probably nobody
ever used them.  So we would end up maintaining
compatibility for quirks nobody ever used.

To summarize, we make all indexing macros read TERM and
SUBTERM arguments verbatim (unconditionally, no need for a
call to \verbatimindex{i}), and write them as is to the .idx
file.  For non-silent indexing macros, we use the primitive
\scantokens or its emulation from texinfo.tex, to rescan and
typeset the verbatim arguments.

I'll do this and announce when the new eplain.tex is ready
for testing :).

Thanks,
Oleg