let (:ok, corpus) = fetch("https://alea.ludus.dev/twc/corpus/raw/branch/main/jarg2912.txt")
let corpus_clean = do corpus > downcase > words

let pattern_len = 5
let corpus_len = count(corpus_clean)
let start_position = random(0, sub(corpus_len, pattern_len))
let starting_ngram = slice_n(corpus_clean, start_position, pattern_len)

fn press! {
  (text, pat, 0, res) -> res
  (text, pat, i) -> press!(text, pat, i, "")
  (text, pat, i, res) -> {
    let ind = random(indices_of(text, last(pat)))
    let new_pat = slice_n(corpus_clean, inc(ind), count(pat))
    let new_res = concat(trim(res), " ", sentence(new_pat))
    press!(text, new_pat, dec(i), new_res)
  }
}

press!(corpus_clean, starting_ngram, 4)