Re: [Tcllib-devel] TBWidget Branch (please help on cvs organisation)

[Andreas K. <and...@ac...>]

Donald G Porter wrote:
> Jeff Hobbs wrote:
>>> Concerning compatibility: I agree it is hard to keep compatible with old 
>>> Tk releases. I'm really used to operators such as {*}, eq, ne,... and I 
>>> don't realize anymore they only exist since Tcl 8.5. I really think we 
>>> should move forward - after all bug fixing on Tk 8.4 has also stopped. 
>>> People who keep using 8.4, can also keep using BWidget 1.9.
> 
> If you drop support for an older Tcl or Tk, be sure to use filtering
> in the index script so that if your new BWidget release gets installed
> within reach of one of those older Tcl or Tk libraries, they continue
> to get the older BWidget version they can use, and not the new one that
> will fail.

Don is talking about code like

	andreask@gila:~/lsf/tcllib/modules> cat amazon-s3/pkgIndex.tcl
	# pkgIndex.tcl --
	# Copyright (c) 2006 Darren New
	# This is for the Amazon S3 web service packages.

	if {![package vsatisfies [package provide Tcl] 8.5]} {return}

	package ifneeded xsxp 1.0 [list source [file join $dir xsxp.tcl]]
	package ifneeded S3 1.0.0 [list source [file join $dir S3.tcl]]

I.e. code which prevents the registration of the package if the Tcl core 
running the script is not up to snuff to support the package.

That way an older Tcl will not even see the newer package, and keep using the 
older one. Assuming that both are installed.


Andreas