Basic doubt in tcl

Hi All
I have one confusion
set a ss
puts {$a} ;# it will print $a (no substitution)

by this i get feeling anything in braces does not substitute by its
value
then why does expr {$a * 3} work? or same thing in catch command.

Sorry if it is an stupid question.
If any tutorial available on command execution mechanism in tcl please
give me link.
.

Relevant Pages

  • Re: Basic doubt in tcl
    ... by this i get feeling anything in braces does not substitute by its ... Or, to expand a little, that's what expr does. ...
    (comp.lang.tcl)
  • Basic doubt in tcl
    ... by this i get feeling anything in braces does not substitute by its ... then why does expr work? ... If any tutorial available on command execution mechanism in tcl please ...
    (comp.lang.tcl)