gistfile1.pl

function to_regex(array,    regex, property, value) {
    regex = ""
    for (property in array) {
         value = array[property]
         gsub(/\W/, "\\\\&", value)
         regex = regex value "|"
    }
    return "(" substr(regex, 1, length(regex) - 1) ")"
}
BEGIN {
    words[1] = "a"
    words[2] = "an"
    words[3] = "table"
    words[4] = "table?"
    regex = to_regex(words)
    print regex
    string = "Is an apple lying on a table?"
    gsub(regex, "<&>", string)
    print string
}