From acc950807e0b2c72c8ee9143a4e23558134092bc Mon Sep 17 00:00:00 2001
From: "Patrick J. Burns" <patrick@diyclassics.org>
Date: Sun, 9 Apr 2023 07:06:08 -0400
Subject: [PATCH] Add noun chunking to la syntax iterators

---
 spacy/lang/la/__init__.py               |  2 +
 spacy/lang/la/syntax_iterators.py       | 85 +++++++++++++++++++++++++
 spacy/tests/lang/la/test_noun_chunks.py | 52 +++++++++++++++
 3 files changed, 139 insertions(+)
 create mode 100644 spacy/lang/la/syntax_iterators.py
 create mode 100644 spacy/tests/lang/la/test_noun_chunks.py

diff --git a/spacy/lang/la/__init__.py b/spacy/lang/la/__init__.py
index 15b87c5b9..37164c3f3 100644
--- a/spacy/lang/la/__init__.py
+++ b/spacy/lang/la/__init__.py
@@ -2,12 +2,14 @@ from ...language import Language, BaseDefaults
 from .tokenizer_exceptions import TOKENIZER_EXCEPTIONS
 from .stop_words import STOP_WORDS
 from .lex_attrs import LEX_ATTRS
+from .syntax_iterators import SYNTAX_ITERATORS
 
 
 class LatinDefaults(BaseDefaults):
     tokenizer_exceptions = TOKENIZER_EXCEPTIONS
     stop_words = STOP_WORDS
     lex_attr_getters = LEX_ATTRS
+    syntax_iterators = SYNTAX_ITERATORS
 
 
 class Latin(Language):
diff --git a/spacy/lang/la/syntax_iterators.py b/spacy/lang/la/syntax_iterators.py
new file mode 100644
index 000000000..8e36c051d
--- /dev/null
+++ b/spacy/lang/la/syntax_iterators.py
@@ -0,0 +1,85 @@
+# NB: Modified from da on suggestion from https://github.com/explosion/spaCy/issues/7457#issuecomment-800349751 [PJB]
+
+from typing import Union, Iterator, Tuple
+from ...tokens import Doc, Span
+from ...symbols import NOUN, PROPN, PRON, VERB, AUX
+from ...errors import Errors
+
+
+def noun_chunks(doclike: Union[Doc, Span]) -> Iterator[Tuple[int, int, int]]:
+    def is_verb_token(tok):
+        return tok.pos in [VERB, AUX]
+
+    def get_left_bound(doc, root):
+        left_bound = root
+        for tok in reversed(list(root.lefts)):
+            if tok.dep in np_left_deps:
+                left_bound = tok
+        return left_bound
+
+    def get_right_bound(doc, root):
+        right_bound = root
+        for tok in root.rights:
+            if tok.dep in np_right_deps:
+                right = get_right_bound(doc, tok)
+                if list(
+                    filter(
+                        lambda t: is_verb_token(t) or t.dep in stop_deps,
+                        doc[root.i : right.i],
+                    )
+                ):
+                    break
+                else:
+                    right_bound = right
+        return right_bound
+
+    def get_bounds(doc, root):
+        return get_left_bound(doc, root), get_right_bound(doc, root)
+
+    doc = doclike.doc  # Ensure works on both Doc and Span.
+
+    if not doc.has_annotation("DEP"):
+        raise ValueError(Errors.E029)
+
+    if not len(doc):
+        return
+
+    left_labels = [
+        "det",
+        "fixed",
+        "nmod:poss",
+        "amod",
+        "flat",
+        "goeswith",
+        "nummod",
+        "appos",
+    ]
+    right_labels = [
+        "fixed",
+        "nmod:poss",
+        "amod",
+        "flat",
+        "goeswith",
+        "nummod",
+        "appos",
+        "nmod",
+        "det",
+    ]
+    stop_labels = ["punct"]
+
+    np_label = doc.vocab.strings.add("NP")
+    np_left_deps = [doc.vocab.strings.add(label) for label in left_labels]
+    np_right_deps = [doc.vocab.strings.add(label) for label in right_labels]
+    stop_deps = [doc.vocab.strings.add(label) for label in stop_labels]
+
+    prev_right = -1
+    for token in doclike:
+        if token.pos in [PROPN, NOUN, PRON]:
+            left, right = get_bounds(doc, token)
+            if left.i <= prev_right:
+                continue
+            yield left.i, right.i + 1, np_label
+            prev_right = right.i
+
+
+SYNTAX_ITERATORS = {"noun_chunks": noun_chunks}
diff --git a/spacy/tests/lang/la/test_noun_chunks.py b/spacy/tests/lang/la/test_noun_chunks.py
new file mode 100644
index 000000000..ba8f5658b
--- /dev/null
+++ b/spacy/tests/lang/la/test_noun_chunks.py
@@ -0,0 +1,52 @@
+import pytest
+from spacy.tokens import Doc
+
+
+def test_noun_chunks_is_parsed(la_tokenizer):
+    """Test that noun_chunks raises Value Error for 'la' language if Doc is not parsed.
+    To check this test, we're constructing a Doc
+    with a new Vocab here and forcing is_parsed to 'False'
+    to make sure the noun chunks don't run.
+    """
+    doc = la_tokenizer("Haec est sententia.")
+    with pytest.raises(ValueError):
+        list(doc.noun_chunks)
+
+
+LA_NP_TEST_EXAMPLES = [
+    (
+        "Haec narrantur a poetis de Perseo.",
+        ["DET", "VERB", "ADP", "NOUN", "ADP", "PROPN", "PUNCT"],
+        ["nsubj:pass", "ROOT", "case", "obl", "case", "obl", "punct"],
+        [1, 0, -1, -1, -3, -1, -5],
+        ["poetis", "Perseo"],
+    ),
+    (
+        "Perseus autem in sinu matris dormiebat.",
+        ["NOUN", "ADV", "ADP", "NOUN", "NOUN", "VERB", "PUNCT"],
+        ["nsubj", "discourse", "case", "obl", "nmod", "ROOT", "punct"],
+        [5, 4, 3, -1, -1, 0, -1],
+        ["Perseus", "sinu matris"],
+    ),
+]
+
+
+@pytest.mark.parametrize(
+    "text,pos,deps,heads,expected_noun_chunks", LA_NP_TEST_EXAMPLES
+)
+def test_la_noun_chunks(la_tokenizer, text, pos, deps, heads, expected_noun_chunks):
+    tokens = la_tokenizer(text)
+
+    assert len(heads) == len(pos)
+    doc = Doc(
+        tokens.vocab,
+        words=[t.text for t in tokens],
+        heads=[head + i for i, head in enumerate(heads)],
+        deps=deps,
+        pos=pos,
+    )
+
+    noun_chunks = list(doc.noun_chunks)
+    assert len(noun_chunks) == len(expected_noun_chunks)
+    for i, np in enumerate(noun_chunks):
+        assert np.text == expected_noun_chunks[i]