Rebol [
    Title: "Set-words"
    File: %set-words.r
    Author: "Ladislav Mecir"
    Date: 2-Jun-2009/16:32:17+2:00
]

set-words: func [
    {Get all set-words from a block}
    block [block!]
    /deep {also search in subblocks/parens}
    /local elem words rule here
] [
    words: make block! length? block
    rule: either deep [
        [
            any [
                set elem set-word! (
                    insert tail words to word! :elem
                ) | here: [block! | paren!] :here into rule | skip
            ]
        ]
    ] [
        [
            any [
                set elem set-word! (
                    insert tail words to word! :elem
                ) | skip
            ]
        ]
    ]
    parse block rule
    words
]