Re: Request update of TCL and expect packages

[Charles Wilson <cygwin@cwilson.fastmail.fm>]

Please don't top-post.  Reformatted below.

On 10/27/2011 2:43 PM, Craig Miller wrote:
> On Thu, Oct 27, 2011 at 11:37 AM, Dave <iamdave@glidefree.com> wrote:
>> I hope this isn't a dumb question...

No, it's not a dumb question, but...

>> Since TCL is designed to support multiple versions installed simultaneously,
>> and there are already quite a few Cygwin packages that have dependencies on
>> various versions of libraries, why not have a new TCL85 and EXPECT545
>> packages? Just leave all the other packages that depend on TCL8.4 alone?
>> Perhaps Mr. Miller would volunteer to be the Cygwin package owner for these
>> two new packages. Even if he were to abandon support, the situation would be
>> better since we'd have >much< more modern versions of TCL/EXPECT for Cygwin.
>
> This sounds like a not unreasonable solution (having 2 sets of
> tcl/expect packages). I can see that there might be a confusion factor
> for newbies, so it would be good to get a few more opinions.

Unfortunately, it's not really possible *right now*.  Maybe, going
forward, future versions of (e.g.) tcl8.6 could co-exist with the new
8.5 ones [1].  The problem IIRC is that until recent versions (which
cygwin-tcltk is /not/), all versions of tcl used the same directory to
store their addons.  This means that (old) tcl would "see" and attempt
to load/use the addons built and configured for (new) tcl.  Ditto tk.
Also, as detailed below [1], even then there are other issues with the
dev files that still aren't fixed in upstream. :-(

To make this work (again IIRC) you'd have to backport the relevant
changes to cygwin's ancient tcltk packages, and then rebuild them, as
well as rebuilding the associated addons so that they go into a
non-conflicting location.  That's a lot of effort. I gave it a shot
several years back -- it kinda sorta worked, but not very well.


Now, if the argument is "but I want a GDI version of tk, and you guys
are switching to X!" (rather than "I simply LOVE ancient and obsolete
technology! tcltk-20080420-1/8.4 forever!!eleventy!11!!") -- then...
One alternative would be to build the entire (new) stack with an
alternate prefix (such as /opt/tk-gdi/), with the appropriate patches so
that tk is pure cygwin + GDI (rather than win32ish + GDI, as the
current, ancient, versions are).

I doubt this would have much chance to be added to the distro, but you
can always set up a repo to share this effort, like Yaakov/cygwin-ports
has done.


[1] But Yaakov's package naming choice won't allow that to work
"smoothly".  Basically, the various elements (tcl, tk, itck, etc) would
each need to be "broken up" into subpackages.  Further, /some/ of those
subpackages would need to have "versioned" names -- like we do for
so-called "dll" packages -- while other subpackages would need, e.g.,
alternatives support for conflicting files (e.g. who provides the
unversioned "wish.exe" or "tclsh.exe"?).

However, lest this be taken as a criticism of Yaakov's packages, the
problem is tcl/tk/etc aren't really *set up* for this sort of thing.
You'd need additional patches so that the "build" headers (currently in
/usr/include/*.h) could be moved to (say, /usr/include/tcl8.5/*.h) --
and tcl itself patched so that add-on builds could "find" them there.

It's really a big mess. I posted an attempt at this several years ago,
but it requires a lot of patching and fiddling -- and really should be
handled by upstream.  It's not something distributors -- like Fedora or
cygwin -- should take on themselves.  Until upstream gets its act
together for co-installs...

--
Chuck

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