[Richard Suchenwirth] 2007-09-28 - Since Tcl 8.5 gives us the [apply] command, it is possible to remodel part (or even all?) of the [proc] functionality in its terms, in a devilish cascade of [interp alias] and [apply]:

 interp alias {} proc {} \
    apply {{name argl body} {interp alias {} $name {} apply [list $argl $body]}}

We define an alias named [proc], which overrides the built-in command, to apply to a {name argl body} triplet a codelet that defines an alias ''name'' to apply to the ''argl'' the ''body''. Whew...

Testing (should print 49/a-b-c, did for me):
 proc square {x {y ""}} {if {$y eq ""} {set y $x}; expr {$x*$y}}
 proc foo args {join $args -}

 puts [square 7]/[foo a b c]

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