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Message-ID:  <20110102184949.GA2478@khaled-laptop>
Date:         Sun, 2 Jan 2011 20:49:50 +0200
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From: Khaled Hosny <khaledhosny@EGLUG.ORG>
Subject: Re: LaTeX3 and engines
To: LATEX-L@listserv.uni-heidelberg.de
In-Reply-To:  <4D2067C4.1040909@morningstar2.co.uk>
Precedence: list
Status: R

On Sun, Jan 02, 2011 at 11:55:48AM +0000, Joseph Wright wrote:
> On 01/01/2011 23:07, Khaled Hosny wrote:
> >Even for "western European languages" Unicode and smart fonts (both not
> >supported "natively" pdftex) have been the norm for decades now; 8bit
> >encodings and type1 fonts are obsolete and almost nobody outside tex
> >community is using them. There is a growing body of fonts, for example,
> >that can not be used with pdftex without pre-processing, if at all. The
> >fact that pdftex can do some jobs is just keeping with the status quo
> >and not moving forward, IMO. I think a new system like latex3 can be a
> >good opportunity to get rid of legacy craft that tex have been carrying
> >around over the year; no need to keep supporting it (when every one else
> >is moving away from it) tell the eternity.
> 
> There are a *lot* of documents created using LaTeX2e which do not
> need to go beyond what pdfTeX can do, so there are two sides to
> this. How you see the balance probably depends on your personal
> position.
> 
> Now, speaking personally I also see the point of accepting that
> things move on (it would make life a lot easier in some areas).
> However, LaTeX2e has been successful partly because of the caution
> the Project has always applied to making changes. So any change in
> engine support will need to be backed up by good reasons, not simply
> 'it seems like a good idea' without any clear code to back this up.
> 
> (On the 'support to eternity' question, there are lots of people who
> won't even use LaTeX2e because 'it is not stable enough'. So again
> there is a balance here.)

I still don't see why the kind of people who would stick to type1 and 8
bit encodings (or hackish, half broken utf-8) would be welling to switch
to latex3 since they would be more resistant to any change. (by latex3
here I refer to the, rather hypothetical right now, complete standalone
latex3 system not the programming interface used by some latex2e
packages.)

Again, my main question is: if they can keep doing what they do right
now with pdftex (since luatex should be supporting all of it), why not
give the extra functionality to the people who want/need it; programming
to the least common denominator is just tying the users of new engines
by the limitation of old ones.

I'm not suggesting that any one do any thing, I'm just trying to
understand.

> >>As I said earlier, we decided to require \pdfstrcmp after some
> >>applications came up where the alternatives were a bad idea
> >>(difference in expandability with different supported engines). So
> >>this might change as we develop more code. I can only comment on
> >>what we have now, where there is no strong case for dropping support
> >>for pdfTeX. (Indeed, almost all of the day-to-day testing I do uses
> >>pdfTeX as it remains my default engine. LuaTeX is a lot slower, I'm
> >>afraid, quite apart from questions about bugs introduced by the
> >>ongoing changes.)
> >
> >I'd be interested to know more about this slowness, my own tests shows
> >that luatex 0.60 is just 1.3 to 1.6 as slower as pdftex, not that
> >significant IMO, and that is testing with "stock" format, code written
> >to take advantage of luatex features can be much faster than comparable
> >pdftex code (in context, for example, certain operations are done tens
> >of times faster in luatex than in pdftex).
> 
> I see quite a lot of 'start up' time with LuaTeX, but have never
> done any formal testing. The start up time is important to me as
> most of my test documents are rather short, so the start up is a
> large chunk of the total. Things might well be different with larger
> documents.

AFAIK the startup delay was a misconfiguration of luatex formats in
texlive2009 (and may be before) and it got fixed in texlive2010.

Regards,
 Khaled

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer