im_prune_org_chart

im_prune_org_chart   tree

deletes all leaves where currently_employed_p is set to vacant position

Source code:

    set result [list [head $tree]]
    # First, recursively process the sub-trees.
    foreach subtree [tail $tree] {
	set new_subtree [im_prune_org_chart $subtree]
	if { ![null_p $new_subtree] } {
	    lappend result $new_subtree
	}
    }
    # Now, delete vacant leaves.
    # We also delete vacant inner nodes that have only one child.
    # 1. if the tree only consists of one vacant node
    #    -> return an empty tree
    # 2. if the tree has a vacant root and only one child
    #    -> return the child 
    # 3. otherwise
    #    -> return the tree 
    if { [thd [head $result]] == "f" } {
	switch [llength $result] {
	    1       { return [list] }
	    2       { return [snd $result] }
	    default { return $result }
	}
    } else {
	return $result
    }