def wavycase(text)
    make_letter_uppercase = false
    text.chars.map {|character|
        if is_letter?(character) then
            make_letter_uppercase = !make_letter_uppercase
            wavycase_character(make_letter_uppercase, character)
        else
            character
        end
    }.join("")
end

def is_letter?(character)
    character =~ /[[:alpha:]]/
end

def wavycase_character(make_letter_uppercase, character)
    if make_letter_uppercase then
        character.upcase
    else
        character.downcase
    end
end