mirror of https://github.com/explosion/spaCy.git
130 lines
4.9 KiB
Cython
130 lines
4.9 KiB
Cython
# coding: utf8
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# cython: infer_types=True
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# cython: bounds_check=False
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# cython: profile=True
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from __future__ import unicode_literals
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from libc.string cimport memcpy, memset
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from .doc cimport Doc, set_children_from_heads, token_by_start, token_by_end
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from .span cimport Span
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from .token cimport Token
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from ..lexeme cimport Lexeme, EMPTY_LEXEME
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from ..structs cimport LexemeC, TokenC
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from ..attrs cimport *
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cdef class Retokenizer:
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'''Helper class for doc.retokenize() context manager.'''
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cdef Doc doc
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cdef list merges
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cdef list splits
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def __init__(self, doc):
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self.doc = doc
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self.merges = []
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self.splits = []
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def merge(self, Span span, attrs=None):
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'''Mark a span for merging. The attrs will be applied to the resulting
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token.'''
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self.merges.append((span.start_char, span.end_char, attrs))
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def split(self, Token token, orths, attrs=None):
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'''Mark a Token for splitting, into the specified orths. The attrs
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will be applied to each subtoken.'''
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self.splits.append((token.start_char, orths, attrs))
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def __enter__(self):
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self.merges = []
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self.splits = []
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return self
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def __exit__(self, *args):
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# Do the actual merging here
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for start_char, end_char, attrs in self.merges:
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start = token_by_start(self.doc.c, self.doc.length, start_char)
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end = token_by_end(self.doc.c, self.doc.length, end_char)
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_merge(self.doc, start, end+1, attrs)
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for start_char, orths, attrs in self.splits:
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raise NotImplementedError
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def _merge(Doc doc, int start, int end, attributes):
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"""Retokenize the document, such that the span at
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`doc.text[start_idx : end_idx]` is merged into a single token. If
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`start_idx` and `end_idx `do not mark start and end token boundaries,
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the document remains unchanged.
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start_idx (int): Character index of the start of the slice to merge.
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end_idx (int): Character index after the end of the slice to merge.
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**attributes: Attributes to assign to the merged token. By default,
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attributes are inherited from the syntactic root of the span.
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RETURNS (Token): The newly merged token, or `None` if the start and end
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indices did not fall at token boundaries.
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"""
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cdef Span span = doc[start:end]
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cdef int start_char = span.start_char
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cdef int end_char = span.end_char
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# Get LexemeC for newly merged token
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new_orth = ''.join([t.text_with_ws for t in span])
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if span[-1].whitespace_:
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new_orth = new_orth[:-len(span[-1].whitespace_)]
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cdef const LexemeC* lex = doc.vocab.get(doc.mem, new_orth)
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# House the new merged token where it starts
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cdef TokenC* token = &doc.c[start]
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token.spacy = doc.c[end-1].spacy
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for attr_name, attr_value in attributes.items():
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if attr_name == TAG:
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doc.vocab.morphology.assign_tag(token, attr_value)
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else:
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Token.set_struct_attr(token, attr_name, attr_value)
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# Make sure ent_iob remains consistent
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if doc.c[end].ent_iob == 1 and token.ent_iob in (0, 2):
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if token.ent_type == doc.c[end].ent_type:
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token.ent_iob = 3
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else:
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# If they're not the same entity type, let them be two entities
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doc.c[end].ent_iob = 3
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# Begin by setting all the head indices to absolute token positions
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# This is easier to work with for now than the offsets
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# Before thinking of something simpler, beware the case where a
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# dependency bridges over the entity. Here the alignment of the
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# tokens changes.
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span_root = span.root.i
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token.dep = span.root.dep
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# We update token.lex after keeping span root and dep, since
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# setting token.lex will change span.start and span.end properties
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# as it modifies the character offsets in the doc
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token.lex = lex
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for i in range(doc.length):
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doc.c[i].head += i
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# Set the head of the merged token, and its dep relation, from the Span
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token.head = doc.c[span_root].head
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# Adjust deps before shrinking tokens
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# Tokens which point into the merged token should now point to it
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# Subtract the offset from all tokens which point to >= end
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offset = (end - start) - 1
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for i in range(doc.length):
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head_idx = doc.c[i].head
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if start <= head_idx < end:
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doc.c[i].head = start
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elif head_idx >= end:
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doc.c[i].head -= offset
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# Now compress the token array
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for i in range(end, doc.length):
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doc.c[i - offset] = doc.c[i]
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for i in range(doc.length - offset, doc.length):
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memset(&doc.c[i], 0, sizeof(TokenC))
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doc.c[i].lex = &EMPTY_LEXEME
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doc.length -= offset
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for i in range(doc.length):
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# ...And, set heads back to a relative position
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doc.c[i].head -= i
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# Set the left/right children, left/right edges
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set_children_from_heads(doc.c, doc.length)
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# Clear the cached Python objects
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# Return the merged Python object
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return doc[start]
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