rules.datalog

top_words_starting_with[word, prefix, text_id, count] :=
    *Word{ word, count, text_id },
    prefix[prefix],
    starts_with(word, prefix)

texts_with_word_starting_with[text_id, word, count, url, prefix] :=
    *Text{ text_id, url },
    *Word{ word, text_id , count},
    prefix[prefix],
    starts_with(word, prefix)

words_ending_with[word, suffix, text_id, count] :=
    *Word{ word, count, text_id },
    suffix[suffix],
    ends_with(word, suffix)

texts_with_word_ending_with[text_id, word, count, url, suffix] :=
    *Text{ text_id, url },
    *Word{ word, text_id, count },
    suffix[suffix],
    ends_with(word, suffix)

words_containing[word, substr, text_id, count] :=
    *Word{ word, count, text_id },
    substring[substr],
    str_includes(word, substr)

texts_containing[text_id, substr, url] :=
    *Text{ text_id, url, text },
    substring[substr],
    str_includes(text, substr)

word_ends[word, suffix, text_id] :=
    *Word{ word, text_id },
    suffix[suffix],
    ends_with(word, suffix)