ometa multiword{
    word                  = letter+:w                                               -> {kind: 'word', value: w.join('')},
    scanner               = space* word,
    token :k              = scanner:t ?(t.kind==k)                                  -> t.value,
    isKeyword  :x         = ?multiword._isKeyword(x),

    isKeywordStart :p :q = &(space seq(q) "word":w) {q != '' ? q + ' ' + w : w}:w {p + ' ' + w}:n 
                                (isKeyword(n) -> true | isKeywordStart(p, w) -> true),

    keywordR :p           = "word":w {p!=''?p+' '+w:w}:w (isKeyword(w) -> w | keywordR(w):a -> a),
    keyword               = keywordR(''):k                                          -> [#keyword, k],

    text                  = ("word":k ~isKeyword(k) ~isKeywordStart(k,'') -> k)*:t  -> ['text', t.join(' ')],
    expr                  = keyword:k text:t keyword:e                              -> [k, t, e]
}

multiword.keywords  = {}
keywords = ["one thing", "two or more things"]
for (var idx = 0; idx < keywords.length; idx++){multiword.keywords[keywords[idx]] = true}
multiword._isKeyword = function(k) { return this.keywords.hasOwnProperty(k) }

sentence = 'one thing can have two or more things'

multiword.matchAll(sentence, 'expr')