[XeTeX] Confused (why are ignored characters not "removed from the input" as per Eijkhout's TeX by Topic ?)
Philip Taylor (Hellenic Institute)
P.Taylor at Hellenic-Institute.Uk
Sun Apr 16 18:44:19 CEST 2023
On 16/04/2023 17:37, Jonathan Kew wrote:
> First note: I see the same result with plain TeX. So not a XeTeX issue.
Agreed, but as I use only XeTeX this seemed the right place to ask. I
did test with PdfTeX (not having plain TeX in my TeXworks armoury) and
PdfTeX did much the same but put a real <tab> in the transcript as
opposed to ^^I.
> Anyway, this is expected behavior. The ^^I isn't part of the offending
> control sequence; it's just the preceding context on the line, which
> is what normally appears in a TeX error message.
OK, so I should have realised that in the absence of a leading "\", ^^I~
could not possibly be a control sequence and therefore the "~" had to be
an active character. That fact had passed me by ...
> Ignored characters are not "removed from the input" (despite anything
> Eijkhout says); they're still present, just ignored.
Having consulted Eijkhout first, I did then search the TeXbook to see if
I could find a definitive statement concerning the treatment of ignored
characters but failed to do so — perhaps I should search the PDF version
rather than the printed ...
--
/Philip Taylor/
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://tug.org/pipermail/xetex/attachments/20230416/d9a7bbfb/attachment.html>
More information about the XeTeX
mailing list.