''[Darren New] wrote in [the comp.lang.tcl newsgroup] on 2002-01-16:''

Something someone here said made me think of this. Talk about changing
the syntax of a language...


 proc where {what} {
    set caller [info level -1]
    set body [info body $caller]
    set body [split $body \n]
    foreach line $body {
        if {-1 != [string first $what $line]} {
            # Or do more complicated processing
            puts $line
        }
    }
    return -code return
 }

 proc here {} {
    where zip
    zippidy doo dah
    zippidy ahy
    Oh my my what a wonderful day.
    zippy the pinhead says
    drink plenty of fluids
 }

 here
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As ''where'' returns ''-code return'' (and thus terminates its caller as well), anything after it is not seen by the Tcl parser. Instead, ''where'' "eats" its caller's body and does with it what it pleases... Amazing food for thought. ([RS])
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[Arts and crafts of Tcl-Tk programming]