Which of these is better and why?

    button .b
    rename .b .b:cmd
    proc .b { args } "eval [list WidgetHandler .b] \$args"

or

    button .b
    rename .b .b:cmd
    interp alias {} .b {} WidgetHandler .b

[MS] prefers the second, for both clarity and performance reasons (no string parsing at run time).