app.ddlog

chunk?(
    @key sent_id bigint,
    @key word_id bigint,
    tag text
).
tags(tag text).

# input data ##################################################################
words_raw(
  sent_id bigint,
  word_id bigint,
  word text,
  pos text,
  true_tag text
).

words(
  sent_id bigint,
  word_id bigint,
  word text,
  pos text,
  true_tag text,
  tag text
).

# supervision / scope of tags #################################################
chunk(s, word, tag) = (
  if tag = tag_supervised then TRUE
                          else NULL
  end
) :-
  words(s, word, _, pos, _, tag_supervised),
  tags(tag).

# TODO the following if-then-else can go directly to the supervision rule once DDlog supports true unification (tag_supervised = if ... end in the body)
words(sent_id, word_id, word, pos, true_tag,
             if true_tag = "B-UCP"        then NULL
        else if true_tag = "I-UCP"        then NULL
        else if strpos(true_tag, "-") > 0 then split_part(true_tag, "-", 2)
        else if true_tag = "O"            then "O"
        else                                   NULL
        end) :-
  words_raw(sent_id, word_id, word, pos, true_tag).

# features ####################################################################
word_features(
  sent_id bigint,
  word_id bigint,
  feature text
).

function ext_features
  over (sent_id bigint, word_id1 bigint, word1 text, pos1 text, word2 text, pos2 text)
  returns rows like word_features
  implementation "udf/ext_features.py" handles tsv lines.

word_features +=
  ext_features(s, w1, word1, pos1, word2, pos2) :-
  words(s, w1, word1, pos1, _, _),
  words(s, w2, word2, pos2, _, _),
  [w1 = w2 + 1],
  word1 IS NOT NULL.

@weight(f, tag)
chunk(s, w, tag) :- word_features(s, w, f).

# linear chains ###############################################################
@weight(tag1, tag2)
chunk(s, w1, tag1) ^ chunk(s, w2, tag2) :- w2 = w1 + 1.

# skip chain ##################################################################
@weight(tag1, tag2)
chunk(s, w1, tag1) ^ chunk(s, w2, tag2) :- w1 < w2.