## String#splice

    require 'facets/string/splice'

    a = "HELLO"
    a.splice(1).assert == "E"
    a.assert == "HLLO"

range

    a = "HELLO"
    a.splice(1..2).assert == "EL"
    a.assert == "HLO"

store

    a = "HELLO"
    a.splice(1, "X")
    a.assert == "HXLLO"

This could be done if class of 2nd arg is checked.

    #Unit :splice_length
    #  a = "HELLO"
    #  a.splice(1,2).assert == "EL"
    #  a.assert == "HLO"
    #end

