Will Robertson <[log in to unmask]> wrote:

> On 11/02/2010, at 8:42 AM, Philipp Stephani wrote:
> 
> > However, any of these has to be done quickly: If LaTeX 3 won't be
> > finished before LuaTeX, it will be obsolete anyway. 
> 
> LaTeX3 and LuaTeX are orthogonal; one does not deprecate the
> other. Certain aspects of the work the LaTeX3 project have done, such
> as the expl3 macro language, might become less useful when/if LuaTeX
> is the *only* widely used TeX engine. But until then LaTeX3 will not
> assume the presence of a Lua programming environment. 
> 
> LuaTeX will not be backwards compatible with pdfTeX in the generated
> output (i.e., two identical documents may have slightly different
> hyphenation/justification choices and therefore different page
> breaks). While the changes will obviously be rather small, I don't
> think anyone can really predict when pdfTeX will stop being used. 

while this is all true, i don't believe it's the point philipp was
making.

at a certain point, latex 3 will lose the support of people sitting
around waiting for it -- as they get older, they'll conclude there's no
point in taking it up for the productive time left to them.

in parallel, the arrival of "production" luatex is coming along fast,
and some time in 2012[*], one assumes that the bright young things will
be wanting to use it.  if they're switching engine, they might look for
a new package, and if latex 3 isn't around at that time, it will have
missed a window.

i thought philipp was suggesting that the luatex 2012 date may present a
final window of opportunity for latex.  the real point is that there
_needn't_ be a "physical" causal relationship between luatex and latex 3
for the final advent of luatex to kill of the ambitions of latex 3.

robin

[*] d.v.