Re: About Tcl syntax...

{=}{$a + $b}  is equivalent to what I suggested.. {#}{$a + b}

I think this syntax is nice, in that you could unbrace the expression
in certain places by removing whitespace.
e.g  {=}$a+$b

I think this is one of the 'cleaner' suggestions - and I haven't seen
any comments on why this wouldn't be a good idea.

If we're going down this route how about something like?...

${$a + $b}

...or...

%{$a + $b}

...I think that having braces around the expression makes the grouping
more clear.

Best Regards,
=Adrian=
.