What does {*} do in TCL?

Question

I have used some TCL, but this construction stumps me.

When $res = \"Table does not exist\", what will the following return?

[list [list {*}$res]]
         


        

Answer 1

Yeah I always find that construction troublesome too. It used be called expand and then they cleverly renamed it to {*} (very memorable!). Anyway I've seen it used to expand a list to make the list contents available.

See this example for an idea of how it works:

% set c [list a b]
a b
% set d [list e f]
e f
% set x [list $c {*}$d]
{a b} e f
% set y [lindex $x 2]
f
% set y [lindex $x 1]
e
% set y [lindex $x 0]
a b