Variants vs. new ports for different version

[Frank Schima]

Hi all,


What's the best practice for handling ports with different versions?

For example, take tcl/tk <http://www.tcl.tk/software/tcltk/>.  
Currently it is up to version 8.5.2 and the port files for tcl and tk  
are both using that. However, the 8.4 tree is also still updated.  
MacPorts does not support the 8.4.x versions. But blt, for one,  
conflicts with tcl/tk 8.5.2 and needs 8.4.x to be used.

I was planning to add support for tcl and tk 8.4.19. Is it alright to  
just add a variant on the ports for the 8.4.x version? Obviously the  
other way is to create new tcl84 and tk84 Portfiles.

The advantage to using a variant is that there are more than one other  
ports that depend on tcl/tk and so they, in theory, would not need to  
be changed. However, in the case of blt, it would need to depend on  
the 8.4.x variant of tcl and tk. It's not clear to me from reading the  
wiki if it's possible to depend on a specific variant. Can someone  
kindly explain if that's possible?

Furthermore, it appears that it is not possible to install both 8.5.x  
and 8.4.x versions of tcl and tk at the same time. So only one should  
be allowed.

Are there other ports like this and what has been done?


Cheers!
Frank