The best way to copy a list?

Is using `lmap` the best way to copy a list? For example:

    package require struct::list 1
    set a {a bc def ghij klmno}
    # is the following the best way to copy a list?
    set b [lmap x $a {expr {$x}}]
    puts "a={$a} b={$b} a==b=[struct::list equal $a $b]"

Output:

    a={a bc def ghij klmno} b={a bc def ghij klmno} a==b=1