guess the number

package require Tk

namespace eval guess {
    variable max 100
    variable min 1
    variable count -1
    variable guess 0
    namespace export *
}

proc guess::gui {} {
    pack [label .g]
    pack [frame .c] -pady 5
    pack [button .c.l -text "Lower" -command guess::lower] -side left -padx 3
    pack [button .c.h -text "Higher" -command guess::higher] -side left -padx 3
    pack [button .c.ok -text "Done" -command guess::done] -side left -padx 3
    guess::next
}

proc guess::next {} {
    variable min
    variable max
    variable guess
    variable count
    incr count
    set guess [expr {($max+$min)/2}]
    .g conf -text "The number is: $guess ?"
}

proc guess::higher {} {
    variable guess
    variable min $guess
    guess::next
}

proc guess::lower {} {
    variable guess
    variable max $guess
    guess::next
}

proc guess::done {} {
    variable count
    .g conf -text "Guessed it in $count tries."
    .c.ok conf -text Exit -command exit
}

guess::gui