uplevel.tcl

#!/usr/bin/env tclsh
proc sum {k m n e} {
    set r 0
    for {set k $m} {$k < $n} {incr k} {
        set r [expr {$r + [uplevel 1 [list set k $k]; uplevel 1 $e]}]
    }
    return $r
}

set test [sum k 1 5 {expr {pow($k, 2)}}]