Part of my reason for being so hellbent upon proliferating tänzer is to improve the state of affairs for Tcl's perception by the wider community. It's a beautiful language, and a well-considered ecosystem. It never really ceased being that as it aged ever so gracefully, so I figure I shall become some larger-than-life PARTY HARD AND LISTEN TO BEAUTIFUL MUSIC! figurehead to spread some cheer and joy in the community and inspire some newfound personal pride in people's works.
+ It combines macro ish text substitution with really, really, really good scoping and loop constructs.
+ A built in event handler is awesome.
+ Tk widgets look just fine for the one off GUI that routinizes a single repetitive task.
+ (Surprisingly) I almost never need float math in a script, one of the things it's not good at.
+ Tcl doesn't try to provide what should be done in C anyway (Python, Perl, Ruby I'm looking at you....)
Wait, you like the upvar stuff?
Also, i know of no other language with macro like substitution along with real local variables.
After being impressed by the "GopherJS" golang to js transpiler, I would love to see a corresponding Tcl/Tk to js transpiler, particularly one with Tk supported as transparently as possible in a browser canvas (or whatever). Greater than 90% of the GUI utilities I write can be handled using Tk's stock widgets. The ability quickly mash together a Tk interface in Tcl/Tk and compile it to js would be a productivity multiplier.
It's almost 2015 and front-ends are still a bear to write and maintain and keeping up with the js framework fads is exhausting. GUI development can and should be as easy as Tk made it ~20 years ago.
https://github.com/aidanhs/emtcl
Drop in on #Tcl on freenode and say hello!