From: Hans Hagen <pragma@wxs.nl>
To: ntg-context@ntg.nl
Subject: Re: Unicode question
Date: Thu, 12 Mar 2015 21:52:59 +0100 [thread overview]
Message-ID: <5501FCAB.4090706@wxs.nl> (raw)
In-Reply-To: <CAG5iGsA5sgZ0RV-7DBXGO-w8xwCzHCMzjCB+2bmFo7QsKtdhwg@mail.gmail.com>
On 3/12/2015 9:41 PM, luigi scarso wrote:
>
>
> On Thu, Mar 12, 2015 at 7:55 PM, Hans Hagen <pragma@wxs.nl
> <mailto:pragma@wxs.nl>> wrote:
>
> it's actually a bug ... it is ok to map an invalid character in the
> input to 0xFFFD, halt and continue when permitted, but the method
> used in luatex thereby obscures a valid 0xFFFD in the input
>
> FFFD REPLACEMENT CHARACTER
> • used to replace an incoming character whose
> value is unknown or unrepresentable in
> Unicode
the question is not what to do when an invalid character comes in, in
that case luatex can replace it by 0xFFFD and issue a error as now,
but when the input hasn't an 0xFFFD then luatex should just carry on as
0xFFFD is a *valid* character
it is quite easy for a macro package to trigger an error as
\catcode"FFFD=15
will do thatm but it's impossible for a macro package to intercept the
weird interception by luatex's input handler
> The meaning of FFFD is not "typeset a question mark on a black box" as in �
> (which depends to font in anycase so in principle it's possible to see
> something completely different in a new version of the font)
> but to signal something potentially wrong with a symbol that currently
> in most cases is �.
> Misusing the meaning is not bad di per se, but in this specific case
> I think luatex is correct to be conservative and ask to the user what to do;
> context --batchmode
> typesets the document,
> writes the messages on the log,
> and ends with -1 , so an automatic agent is also alerted.
you cannot force a user to use \batchmode and -1 would abort a wrapper
thereby leading to an invalid document; it means that luatex can never
typeset a document where char 0xFFFD is being typeset and luatex should
not be normative
not accepting 0xFFFD in the input is a bug
Hans
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prev parent reply other threads:[~2015-03-12 20:52 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-12 7:48 Manfred Lotz
2015-03-12 15:41 ` Ulrike Fischer
2015-03-12 16:35 ` Arthur Reutenauer
2015-03-12 18:08 ` Manfred Lotz
2015-03-12 19:04 ` Hans Hagen
2015-03-12 17:57 ` Manfred Lotz
2015-03-12 18:55 ` Hans Hagen
2015-03-12 20:41 ` luigi scarso
2015-03-12 20:52 ` Hans Hagen [this message]
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