scanl

scanl   f   e   xs

takes a binary function f, a start element e and a list {x1 x2 ...} and returns {e (f e x1) (f (f e x1) x2) ...}

Source code:

    set current_element $e
    set result [list $e]
    foreach x $xs {    
	set current_element [eval_binary $f $current_element $x] 
	lappend result $current_element
    }
    return $result