The top level of parenthesis-es is left out, the other levels replaced by brackets :). But joking aside, I greatly enjoy both Lisp and Tcl as languages.
A huge, seriously annoying problem with TCL is lack of deterministic cleanup for resources. If you don't manually close a filehandle, for example, it will leak. Doing this sort of bookkeeping in 2015 is infuriating.
This illustrates how you can use Tcl to ensure that files get closed even when errors happen by combining catch, close and return (from the Tcl manual):
proc withOpenFile {filename channelVar script} {
upvar 1 $channelVar chan
set chan [open $filename]
catch {
uplevel 1 $script
} result options
close $chan
return -options $options $result
}
You could easily wrap the middle uplevel in a catch block to handle exceptions, and this sort of "with" construct is pretty common in a lot of very popular languages today.
While it would be nice if this were baked into the language, it's pretty astonishing how extensible Tcl is without even having to touch the realm of C extensions.
I think this precisely one of Tcl's strengths. Few other languages apart from Lisp and Tcl lets you write your own control flow syntax from within the language (and at runtime).
Garbage collecting languages will free memory, but that's all they're good for. C++ destructors will let you close a filehandle, but I know of no other language that will deterministically clean up non-memory resources.
So: What language(s) did you have in mind that do this right?
Lisp for example has unwind-protect, which is guaranteed to run the unwind code when you leave its scope in which way whatever (be it an exception or a return). So this is a reliable way of running clean-up code at the end of a code block.
Not for tcloo objects, channels and file handles. I don't think you get it. In sane languages like C++ you can expect a destructor to call itself no matter where a function exited.
Cool...now I get to play. Perl does it because it goes out of scope once the sub is run. I am pretty sure you can tell TclOO to do the same thing (play time) if it already doesn't do that.
In the end, they all make trade offs depending on the "whim" of the language designer.