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"""Backend to parse patents from the United States Patent Office (USPTO).
The parsers included in this module can handle patent grants pubished since 1976 and
patent applications since 2001.
The original files can be found in https://bulkdata.uspto.gov.
"""
import html
import logging
import re
import xml.sax
import xml.sax.xmlreader
from abc import ABC, abstractmethod
from enum import Enum, unique
from io import BytesIO
from pathlib import Path
from typing import Any, Final, Optional, Union
from bs4 import BeautifulSoup, Tag
from docling_core.types.doc import (
DocItem,
DocItemLabel,
DoclingDocument,
DocumentOrigin,
TableCell,
TableData,
TextItem,
)
from docling_core.types.doc.document import LevelNumber
from pydantic import NonNegativeInt
from typing_extensions import Self, TypedDict, override
from docling.backend.abstract_backend import DeclarativeDocumentBackend
from docling.datamodel.base_models import InputFormat
from docling.datamodel.document import InputDocument
_log = logging.getLogger(__name__)
XML_DECLARATION: Final = '<?xml version="1.0" encoding="UTF-8"?>'
@unique
class PatentHeading(Enum):
"""Text of docling headings for tagged sections in USPTO patent documents."""
ABSTRACT = "ABSTRACT", 2
CLAIMS = "CLAIMS", 2
@override
def __new__(cls, value: str, _) -> Self:
obj = object.__new__(cls)
obj._value_ = value
return obj
@override
def __init__(self, _, level: LevelNumber) -> None:
self.level: LevelNumber = level
class PatentUsptoDocumentBackend(DeclarativeDocumentBackend):
@override
def __init__(
self, in_doc: InputDocument, path_or_stream: Union[BytesIO, Path]
) -> None:
super().__init__(in_doc, path_or_stream)
self.patent_content: str = ""
self.parser: Optional[PatentUspto] = None
try:
if isinstance(self.path_or_stream, BytesIO):
while line := self.path_or_stream.readline().decode("utf-8"):
if line.startswith("<!DOCTYPE") or line == "PATN\n":
self._set_parser(line)
self.patent_content += line
elif isinstance(self.path_or_stream, Path):
with open(self.path_or_stream, encoding="utf-8") as file_obj:
while line := file_obj.readline():
if line.startswith("<!DOCTYPE") or line == "PATN\n":
self._set_parser(line)
self.patent_content += line
except Exception as exc:
raise RuntimeError(
f"Could not initialize USPTO backend for file with hash {self.document_hash}."
) from exc
def _set_parser(self, doctype: str) -> None:
doctype_line = doctype.lower()
if doctype == "PATN\n":
self.parser = PatentUsptoGrantAps()
elif "us-patent-application-v4" in doctype_line:
self.parser = PatentUsptoIce()
elif "us-patent-grant-v4" in doctype_line:
self.parser = PatentUsptoIce()
elif "us-grant-025" in doctype_line:
self.parser = PatentUsptoGrantV2()
elif all(
item in doctype_line
for item in ("patent-application-publication", "pap-v1")
):
self.parser = PatentUsptoAppV1()
else:
self.parser = None
@override
def is_valid(self) -> bool:
return bool(self.patent_content) and bool(self.parser)
@classmethod
@override
def supports_pagination(cls) -> bool:
return False
@override
def unload(self) -> None:
return
@classmethod
@override
def supported_formats(cls) -> set[InputFormat]:
return {InputFormat.XML_USPTO}
@override
def convert(self) -> DoclingDocument:
if self.parser is not None:
doc = self.parser.parse(self.patent_content)
if doc is None:
raise RuntimeError(
f"Failed to convert doc (hash={self.document_hash}, "
f"name={self.file.name})."
)
doc.name = self.file.name or "file"
mime_type = (
"text/plain"
if isinstance(self.parser, PatentUsptoGrantAps)
else "application/xml"
)
doc.origin = DocumentOrigin(
mimetype=mime_type,
binary_hash=self.document_hash,
filename=self.file.name or "file",
)
return doc
else:
raise RuntimeError(
f"Cannot convert doc (hash={self.document_hash}, "
f"name={self.file.name}) because the backend failed to init."
)
class PatentUspto(ABC):
"""Parser of patent documents from the US Patent Office."""
@abstractmethod
def parse(self, patent_content: str) -> Optional[DoclingDocument]:
"""Parse a USPTO patent.
Parameters:
patent_content: The content of a single patent in a USPTO file.
Returns:
The patent parsed as a docling document.
"""
pass
class PatentUsptoIce(PatentUspto):
"""Parser of patent documents from the US Patent Office (ICE).
The compatible formats are:
- Patent Grant Full Text Data/XML Version 4.x ICE (from January 2005)
- Patent Application Full Text Data/XML Version 4.x ICE (from January 2005)
"""
def __init__(self) -> None:
"""Build an instance of PatentUsptoIce class."""
self.handler = PatentUsptoIce.PatentHandler()
self.pattern = re.compile(r"^(<table .*?</table>)", re.MULTILINE | re.DOTALL)
def parse(self, patent_content: str) -> Optional[DoclingDocument]:
try:
xml.sax.parseString(patent_content, self.handler)
except xml.sax._exceptions.SAXParseException as exc_sax:
_log.error(f"Error in parsing USPTO document: {exc_sax}")
return None
doc = self.handler.doc
if doc:
raw_tables = re.findall(self.pattern, patent_content)
parsed_tables: list[TableData] = []
_log.debug(f"Found {len(raw_tables)} tables to be parsed with XmlTable.")
for table in raw_tables:
table_parser = XmlTable(XML_DECLARATION + "\n" + table)
try:
table_data = table_parser.parse()
if table_data:
parsed_tables.append(table_data)
except Exception as exc_table:
_log.error(f"Error in parsing USPTO tables: {exc_table}")
if len(parsed_tables) != len(doc.tables):
_log.error(
f"Number of referenced ({len(doc.tables)}) and parsed "
f"({len(parsed_tables)}) tables differ."
)
else:
for idx, item in enumerate(parsed_tables):
doc.tables[idx].data = item
return doc
class PatentHandler(xml.sax.handler.ContentHandler):
"""SAX ContentHandler for patent documents."""
APP_DOC_ELEMENT: Final = "us-patent-application"
GRANT_DOC_ELEMENT: Final = "us-patent-grant"
@unique
class Element(Enum):
"""Represents an element of interest in the patent application document."""
ABSTRACT = "abstract", True
TITLE = "invention-title", True
CLAIMS = "claims", False
CLAIM = "claim", False
CLAIM_TEXT = "claim-text", True
PARAGRAPH = "p", True
HEADING = "heading", True
DESCRIPTION = "description", False
TABLE = "table", False # to track its position, without text
DRAWINGS = "description-of-drawings", True
STYLE_SUPERSCRIPT = "sup", True
STYLE_SUBSCRIPT = "sub", True
MATHS = "maths", False # to avoid keeping formulas
@override
def __new__(cls, value: str, _) -> Self:
obj = object.__new__(cls)
obj._value_ = value
return obj
@override
def __init__(self, _, is_text: bool) -> None:
self.is_text: bool = is_text
@override
def __init__(self) -> None:
"""Build an instance of the patent handler."""
# Current patent being parsed
self.doc: Optional[DoclingDocument] = None
# Keep track of docling hierarchy level
self.level: LevelNumber = 1
# Keep track of docling parents by level
self.parents: dict[LevelNumber, Optional[DocItem]] = {1: None}
# Content to retain for the current patent
self.property: list[str]
self.claim: str
self.claims: list[str]
self.abstract: str
self.text: str
self._clean_data()
# To handle mathematical styling
self.style_html = HtmlEntity()
@override
def startElement(self, tag, attributes): # noqa: N802
"""Signal the start of an element.
Args:
tag: The element tag.
attributes: The element attributes.
"""
if tag in (
self.APP_DOC_ELEMENT,
self.GRANT_DOC_ELEMENT,
):
self.doc = DoclingDocument(name="file")
self.text = ""
self._start_registered_elements(tag, attributes)
@override
def skippedEntity(self, name): # noqa: N802
"""Receive notification of a skipped entity.
HTML entities will be skipped by the parser. This method will unescape them
and add them to the text.
Args:
name: Entity name.
"""
if self.property:
elm_val = self.property[-1]
element = self.Element(elm_val)
if element.is_text:
escaped = self.style_html.get_greek_from_iso8879(f"&{name};")
unescaped = html.unescape(escaped)
if unescaped == escaped:
_log.debug(f"Unrecognized HTML entity: {name}")
return
if element in (
self.Element.STYLE_SUPERSCRIPT,
self.Element.STYLE_SUBSCRIPT,
):
# superscripts and subscripts need to be under text elements
if len(self.property) < 2:
return
parent_val = self.property[-2]
parent = self.Element(parent_val)
if parent.is_text:
self.text += self._apply_style(unescaped, elm_val)
else:
self.text += unescaped
@override
def endElement(self, tag): # noqa: N802
"""Signal the end of an element.
Args:
tag: The element tag.
"""
if tag in (
self.APP_DOC_ELEMENT,
self.GRANT_DOC_ELEMENT,
):
self._clean_data()
self._end_registered_element(tag)
@override
def characters(self, content):
"""Receive notification of character data.
Args:
content: Data reported by the handler.
"""
if self.property:
elm_val = self.property[-1]
element = self.Element(elm_val)
if element.is_text:
if element in (
self.Element.STYLE_SUPERSCRIPT,
self.Element.STYLE_SUBSCRIPT,
):
# superscripts and subscripts need to be under text elements
if len(self.property) < 2:
return
parent_val = self.property[-2]
parent = self.Element(parent_val)
if parent.is_text:
self.text += self._apply_style(content, elm_val)
else:
self.text += content
def _start_registered_elements(
self, tag: str, attributes: xml.sax.xmlreader.AttributesImpl
) -> None:
if tag in [member.value for member in self.Element]:
# special case for claims: claim lines may start before the
# previous one is closed
if (
tag == self.Element.CLAIM_TEXT.value
and self.property
and self.property[-1] == tag
and self.text.strip()
):
self.claim += " " + self.text.strip()
self.text = ""
elif tag == self.Element.HEADING.value:
level_attr: str = attributes.get("level", "")
new_level: int = int(level_attr) if level_attr.isnumeric() else 1
max_level = min(self.parents.keys())
# increase heading level with 1 for title, if any
self.level = (
new_level + 1 if (new_level + 1) in self.parents else max_level
)
self.property.append(tag)
def _end_registered_element(self, tag: str) -> None:
if tag in [item.value for item in self.Element] and self.property:
current_tag = self.property.pop()
self._add_property(current_tag, self.text.strip())
def _add_property(self, name: str, text: str) -> None:
if not name or not self.doc:
return
if name == self.Element.TITLE.value:
if text:
self.parents[self.level + 1] = self.doc.add_title(
parent=self.parents[self.level],
text=text,
)
self.level += 1
self.text = ""
elif name == self.Element.ABSTRACT.value:
if self.abstract:
heading_text = PatentHeading.ABSTRACT.value
heading_level = (
PatentHeading.ABSTRACT.level
if PatentHeading.ABSTRACT.level in self.parents
else 1
)
abstract_item = self.doc.add_heading(
heading_text,
level=heading_level,
parent=self.parents[heading_level],
)
self.doc.add_text(
label=DocItemLabel.PARAGRAPH,
text=self.abstract,
parent=abstract_item,
)
elif name == self.Element.CLAIM_TEXT.value:
text = re.sub("\\s+", " ", text).strip()
if text:
self.claim += " " + text
self.text = ""
elif name == self.Element.CLAIM.value and self.claim:
self.claims.append(self.claim.strip())
self.claim = ""
elif name == self.Element.CLAIMS.value and self.claims:
heading_text = PatentHeading.CLAIMS.value
heading_level = (
PatentHeading.CLAIMS.level
if PatentHeading.CLAIMS.level in self.parents
else 1
)
claims_item = self.doc.add_heading(
heading_text,
level=heading_level,
parent=self.parents[heading_level],
)
for text in self.claims:
self.doc.add_text(
label=DocItemLabel.PARAGRAPH, text=text, parent=claims_item
)
elif name == self.Element.PARAGRAPH.value and text:
# remmove blank spaces added in paragraphs
text = re.sub("\\s+", " ", text)
if self.Element.ABSTRACT.value in self.property:
self.abstract = (
(self.abstract + " " + text) if self.abstract else text
)
else:
self.doc.add_text(
label=DocItemLabel.PARAGRAPH,
text=text,
parent=self.parents[self.level],
)
self.text = ""
elif name == self.Element.HEADING.value and text:
self.parents[self.level + 1] = self.doc.add_heading(
text=text,
level=self.level,
parent=self.parents[self.level],
)
self.level += 1
self.text = ""
elif name == self.Element.TABLE.value:
# set an empty table as placeholder
empty_table = TableData(num_rows=0, num_cols=0, table_cells=[])
self.doc.add_table(
data=empty_table,
parent=self.parents[self.level],
)
def _apply_style(self, text: str, style_tag: str) -> str:
"""Apply an HTML style to text.
Args:
text: A string containing plain text.
style_tag: An HTML tag name for styling text. If the tag name is not
recognized as one of the supported styles, the method will return
the original `text`.
Returns:
A string after applying the style.
"""
formatted = text
if style_tag == self.Element.STYLE_SUPERSCRIPT.value:
formatted = html.unescape(self.style_html.get_superscript(text))
elif style_tag == self.Element.STYLE_SUBSCRIPT.value:
formatted = html.unescape(self.style_html.get_subscript(text))
return formatted
def _clean_data(self) -> None:
"""Reset the variables from stream data."""
self.property = []
self.claim = ""
self.claims = []
self.abstract = ""
class PatentUsptoGrantV2(PatentUspto):
"""Parser of patent documents from the US Patent Office (grants v2.5).
The compatible format is:
- Patent Grant Full Text Data/XML Version 2.5 (from January 2002 till December 2004)
"""
@override
def __init__(self) -> None:
"""Build an instance of PatentUsptoGrantV2 class."""
self.handler = PatentUsptoGrantV2.PatentHandler()
self.pattern = re.compile(r"^(<table .*?</table>)", re.MULTILINE | re.DOTALL)
@override
def parse(self, patent_content: str) -> Optional[DoclingDocument]:
try:
xml.sax.parseString(patent_content, self.handler)
except xml.sax._exceptions.SAXParseException as exc_sax:
_log.error(f"Error in parsing USPTO document: {exc_sax}")
return None
doc = self.handler.doc
if doc:
raw_tables = re.findall(self.pattern, patent_content)
parsed_tables: list[TableData] = []
_log.debug(f"Found {len(raw_tables)} tables to be parsed with XmlTable.")
for table in raw_tables:
table_parser = XmlTable(XML_DECLARATION + "\n" + table)
try:
table_data = table_parser.parse()
if table_data:
parsed_tables.append(table_data)
except Exception as exc_table:
_log.error(f"Error in parsing USPTO tables: {exc_table}")
if len(parsed_tables) != len(doc.tables):
_log.error(
f"Number of referenced ({len(doc.tables)}) and parsed "
f"({len(parsed_tables)}) tables differ."
)
else:
for idx, item in enumerate(parsed_tables):
doc.tables[idx].data = item
return doc
class PatentHandler(xml.sax.handler.ContentHandler):
"""SAX ContentHandler for patent documents."""
GRANT_DOC_ELEMENT: Final = "PATDOC"
CLAIM_STATEMENT: Final = "What is claimed is:"
@unique
class Element(Enum):
"""Represents an element of interest in the patent application document."""
PDAT = "PDAT", True # any type of data
ABSTRACT = ("SDOAB", False)
SDOCL = ("SDOCL", False)
TITLE = ("B540", False)
CLAIMS = ("CL", False)
CLAIM = ("CLM", False)
PARAGRAPH = ("PARA", True)
HEADING = ("H", True)
DRAWINGS = ("DRWDESC", False)
STYLE_SUPERSCRIPT = ("SP", False)
STYLE_SUBSCRIPT = ("SB", False)
STYLE_ITALIC = ("ITALIC", False)
CWU = ("CWU", False) # avoid tables, chemicals, formulas
TABLE = ("table", False) # to keep track of table positions
@override
def __new__(cls, value: str, _) -> Self:
obj = object.__new__(cls)
obj._value_ = value
return obj
@override
def __init__(self, _, is_text: bool) -> None:
self.is_text: bool = is_text
@override
def __init__(self) -> None:
"""Build an instance of the patent handler."""
# Current patent being parsed
self.doc: Optional[DoclingDocument] = None
# Keep track of docling hierarchy level
self.level: LevelNumber = 1
# Keep track of docling parents by level
self.parents: dict[LevelNumber, Optional[DocItem]] = {1: None}
# Content to retain for the current patent
self.property: list[str]
self.claim: str
self.claims: list[str]
self.paragraph: str
self.abstract: str
self._clean_data()
# To handle mathematical styling
self.style_html = HtmlEntity()
@override
def startElement(self, tag, attributes): # noqa: N802
"""Signal the start of an element.
Args:
tag: The element tag.
attributes: The element attributes.
"""
if tag == self.GRANT_DOC_ELEMENT:
self.doc = DoclingDocument(name="file")
self.text = ""
self._start_registered_elements(tag, attributes)
@override
def skippedEntity(self, name): # noqa: N802
"""Receive notification of a skipped entity.
HTML entities will be skipped by the parser. This method will unescape them
and add them to the text.
Args:
name: Entity name.
"""
if self.property:
elm_val = self.property[-1]
element = self.Element(elm_val)
if element.is_text:
escaped = self.style_html.get_greek_from_iso8879(f"&{name};")
unescaped = html.unescape(escaped)
if unescaped == escaped:
logging.debug("Unrecognized HTML entity: " + name)
return
if element in (
self.Element.STYLE_SUPERSCRIPT,
self.Element.STYLE_SUBSCRIPT,
):
# superscripts and subscripts need to be under text elements
if len(self.property) < 2:
return
parent_val = self.property[-2]
parent = self.Element(parent_val)
if parent.is_text:
self.text += self._apply_style(unescaped, elm_val)
else:
self.text += unescaped
@override
def endElement(self, tag): # noqa: N802
"""Signal the end of an element.
Args:
tag: The element tag.
"""
if tag == self.GRANT_DOC_ELEMENT:
self._clean_data()
self._end_registered_element(tag)
@override
def characters(self, content):
"""Receive notification of character data.
Args:
content: Data reported by the handler.
"""
if self.property:
elm_val = self.property[-1]
element = self.Element(elm_val)
if element.is_text:
if element in (
self.Element.STYLE_SUPERSCRIPT,
self.Element.STYLE_SUBSCRIPT,
):
# superscripts and subscripts need to be under text elements
if len(self.property) < 2:
return
parent_val = self.property[-2]
parent = self.Element(parent_val)
if parent.is_text:
self.text += self._apply_style(content, elm_val)
else:
self.text += content
def _start_registered_elements(
self, tag: str, attributes: xml.sax.xmlreader.AttributesImpl
) -> None:
if tag in [member.value for member in self.Element]:
if (
tag == self.Element.HEADING.value
and not self.Element.SDOCL.value in self.property
):
level_attr: str = attributes.get("LVL", "")
new_level: int = int(level_attr) if level_attr.isnumeric() else 1
max_level = min(self.parents.keys())
# increase heading level with 1 for title, if any
self.level = (
new_level + 1 if (new_level + 1) in self.parents else max_level
)
self.property.append(tag)
def _end_registered_element(self, tag: str) -> None:
if tag in [elm.value for elm in self.Element] and self.property:
current_tag = self.property.pop()
self._add_property(current_tag, self.text)
def _add_property(self, name: str, text: str) -> None:
if not name or not self.doc:
return
if name == self.Element.PDAT.value and text:
if not self.property:
self.text = ""
return
wrapper = self.property[-1]
text = self._apply_style(text, wrapper)
if self.Element.TITLE.value in self.property and text.strip():
title = text.strip()
self.parents[self.level + 1] = self.doc.add_title(
parent=self.parents[self.level],
text=title,
)
self.level += 1
elif self.Element.ABSTRACT.value in self.property:
self.abstract += text
elif self.Element.CLAIM.value in self.property:
self.claim += text
# Paragraph text not in claims or abstract
elif (
self.Element.PARAGRAPH.value in self.property
and self.Element.CLAIM.value not in self.property
and self.Element.ABSTRACT.value not in self.property
):
self.paragraph += text
# headers except claims statement
elif (
self.Element.HEADING.value in self.property
and not self.Element.SDOCL.value in self.property
and text.strip()
):
self.parents[self.level + 1] = self.doc.add_heading(
text=text.strip(),
level=self.level,
parent=self.parents[self.level],
)
self.level += 1
self.text = ""
elif name == self.Element.CLAIM.value and self.claim.strip():
self.claims.append(self.claim.strip())
self.claim = ""
elif name == self.Element.CLAIMS.value and self.claims:
heading_text = PatentHeading.CLAIMS.value
heading_level = (
PatentHeading.CLAIMS.level
if PatentHeading.CLAIMS.level in self.parents
else 1
)
claims_item = self.doc.add_heading(
heading_text,
level=heading_level,
parent=self.parents[heading_level],
)
for text in self.claims:
self.doc.add_text(
label=DocItemLabel.PARAGRAPH, text=text, parent=claims_item
)
elif name == self.Element.ABSTRACT.value and self.abstract.strip():
abstract = self.abstract.strip()
heading_text = PatentHeading.ABSTRACT.value
heading_level = (
PatentHeading.ABSTRACT.level
if PatentHeading.ABSTRACT.level in self.parents
else 1
)
abstract_item = self.doc.add_heading(
heading_text,
level=heading_level,
parent=self.parents[heading_level],
)
self.doc.add_text(
label=DocItemLabel.PARAGRAPH, text=abstract, parent=abstract_item
)
elif name == self.Element.PARAGRAPH.value:
paragraph = self.paragraph.strip()
if paragraph and self.Element.CLAIM.value not in self.property:
self.doc.add_text(
label=DocItemLabel.PARAGRAPH,
text=paragraph,
parent=self.parents[self.level],
)
elif self.Element.CLAIM.value in self.property:
# we may need a space after a paragraph in claim text
self.claim += " "
self.paragraph = ""
elif name == self.Element.TABLE.value:
# set an empty table as placeholder
empty_table = TableData(num_rows=0, num_cols=0, table_cells=[])
self.doc.add_table(
data=empty_table,
parent=self.parents[self.level],
)
def _apply_style(self, text: str, style_tag: str) -> str:
"""Apply an HTML style to text.
Args:
text: A string containing plain text.
style_tag: An HTML tag name for styling text. If the tag name is not
recognized as one of the supported styles, the method will return
the original `text`.
Returns:
A string after applying the style.
"""
formatted = text
if style_tag == self.Element.STYLE_SUPERSCRIPT.value:
formatted = html.unescape(self.style_html.get_superscript(text))
elif style_tag == self.Element.STYLE_SUBSCRIPT.value:
formatted = html.unescape(self.style_html.get_subscript(text))
elif style_tag == self.Element.STYLE_ITALIC.value:
formatted = html.unescape(self.style_html.get_math_italic(text))
return formatted
def _clean_data(self) -> None:
"""Reset the variables from stream data."""
self.text = ""
self.property = []
self.claim = ""
self.claims = []
self.paragraph = ""
self.abstract = ""
class PatentUsptoGrantAps(PatentUspto):
"""Parser of patents documents from the US Patent Office (grants APS).
The compatible format is:
- Patent Grant Full Text Data/APS (from January 1976 till December 2001)
"""
@unique
class Section(Enum):
"""Represent a section in a patent APS document."""
ABSTRACT = "ABST"
SUMMARY = "BSUM"
DETAILS = "DETD"
CLAIMS = "CLMS"
DRAWINGS = "DRWD"
@unique
class Field(Enum):
"""Represent a field in a patent APS document."""
DOC_NUMBER = "WKU"
TITLE = "TTL"
PARAGRAPH = "PAR"
PARAGRAPH_1 = "PA1"
PARAGRAPH_2 = "PA2"
PARAGRAPH_3 = "PA3"
TEXT = "PAL"
CAPTION = "PAC"
NUMBER = "NUM"
NAME = "NAM"
IPC = "ICL"
ISSUED = "ISD"
FILED = "APD"
PATENT_NUMBER = "PNO"
APPLICATION_NUMBER = "APN"
APPLICATION_TYPE = "APT"
COUNTRY = "CNT"
@override
def __init__(self) -> None:
"""Build an instance of PatentUsptoGrantAps class."""
self.doc: Optional[DoclingDocument] = None
# Keep track of docling hierarchy level
self.level: LevelNumber = 1
# Keep track of docling parents by level
self.parents: dict[LevelNumber, Optional[DocItem]] = {1: None}
def get_last_text_item(self) -> Optional[TextItem]:
"""Get the last text item at the current document level.
Returns:
The text item or None, if the current level parent has no children."""
if self.doc:
parent = self.parents[self.level]
children = parent.children if parent is not None else []
else:
return None
text_list: list[TextItem] = [
item
for item in self.doc.texts
if isinstance(item, TextItem) and item.get_ref() in children
]
if text_list:
return text_list[-1]
else:
return None
def store_section(self, section: str) -> None:
"""Store the section heading in the docling document.
Only the predefined sections from PatentHeading will be handled.
The other sections are created by the Field.CAPTION field.
Args:
section: A patent section name."""
heading: PatentHeading
if self.doc is None:
return
elif section == self.Section.ABSTRACT.value:
heading = PatentHeading.ABSTRACT
elif section == self.Section.CLAIMS.value:
heading = PatentHeading.CLAIMS
else:
return None
self.level = heading.level if heading.level in self.parents else 1
self.parents[self.level + 1] = self.doc.add_heading(
heading.value,
level=self.level,
parent=self.parents[self.level],
)
self.level += 1
def store_content(self, section: str, field: str, value: str) -> None:
"""Store the key value within a document section in the docling document.
Args:
section: A patent section name.
field: A field name.
value: A field value name.
"""
if (
not self.doc
or not field
or field not in [item.value for item in PatentUsptoGrantAps.Field]
):
return
if field == self.Field.TITLE.value:
self.parents[self.level + 1] = self.doc.add_title(
parent=self.parents[self.level], text=value
)
self.level += 1
elif field == self.Field.TEXT.value and section == self.Section.ABSTRACT.value:
abst_item = self.get_last_text_item()
if abst_item:
abst_item.text += " " + value
else:
self.doc.add_text(
label=DocItemLabel.PARAGRAPH,
text=value,
parent=self.parents[self.level],
)
elif field == self.Field.NUMBER.value and section == self.Section.CLAIMS.value:
self.doc.add_text(
label=DocItemLabel.PARAGRAPH,
text="",
parent=self.parents[self.level],
)
elif (
field
in (
self.Field.PARAGRAPH.value,
self.Field.PARAGRAPH_1.value,
self.Field.PARAGRAPH_2.value,
self.Field.PARAGRAPH_3.value,
)
and section == self.Section.CLAIMS.value
):
last_claim = self.get_last_text_item()
if last_claim is None:
last_claim = self.doc.add_text(
label=DocItemLabel.PARAGRAPH,
text="",
parent=self.parents[self.level],
)
last_claim.text += f" {value}" if last_claim.text else value
elif field == self.Field.CAPTION.value and section in (
self.Section.SUMMARY.value,
self.Section.DETAILS.value,
self.Section.DRAWINGS.value,
):
# captions are siblings of abstract since no level info is provided
head_item = PatentHeading.ABSTRACT
self.level = head_item.level if head_item.level in self.parents else 1
self.parents[self.level + 1] = self.doc.add_heading(
value,
level=self.level,
parent=self.parents[self.level],
)
self.level += 1
elif field in (
self.Field.PARAGRAPH.value,
self.Field.PARAGRAPH_1.value,
self.Field.PARAGRAPH_2.value,
self.Field.PARAGRAPH_3.value,
) and section in (
self.Section.SUMMARY.value,
self.Section.DETAILS.value,
self.Section.DRAWINGS.value,
):
self.doc.add_text(
label=DocItemLabel.PARAGRAPH,
text=value,
parent=self.parents[self.level],
)
def parse(self, patent_content: str) -> Optional[DoclingDocument]:
self.doc = self.doc = DoclingDocument(name="file")
section: str = ""
key: str = ""
value: str = ""
line_num = 0
for line in patent_content.splitlines():
cols = re.split("\\s{2,}", line, maxsplit=1)
if key and value and (len(cols) == 1 or (len(cols) == 2 and cols[0])):
self.store_content(section, key, value)
key = ""
value = ""
if len(cols) == 1: # section title
section = cols[0]
self.store_section(section)
_log.debug(f"Parsing section {section}")
elif len(cols) == 2: # key value
if cols[0]: # key present
key = cols[0]
value = cols[1]
elif not re.match(r"^##STR\d+##$", cols[1]): # line continues
value += " " + cols[1]
line_num += 1
if key and value:
self.store_content(section, key, value)
# TODO: parse tables
return self.doc
class PatentUsptoAppV1(PatentUspto):
"""Parser of patent documents from the US Patent Office (applications v1.x)
The compatible format is:
- Patent Application Full Text Data/XML Version 1.x (from March 2001 till December
2004)
"""
@override
def __init__(self) -> None:
"""Build an instance of PatentUsptoAppV1 class."""
self.handler = PatentUsptoAppV1.PatentHandler()
self.pattern = re.compile(r"^(<table .*?</table>)", re.MULTILINE | re.DOTALL)
@override
def parse(self, patent_content: str) -> Optional[DoclingDocument]:
try:
xml.sax.parseString(patent_content, self.handler)
except xml.sax._exceptions.SAXParseException as exc_sax:
_log.error(f"Error in parsing USPTO document: {exc_sax}")
return None
doc = self.handler.doc
if doc:
raw_tables = re.findall(self.pattern, patent_content)
parsed_tables: list[TableData] = []
_log.debug(f"Found {len(raw_tables)} tables to be parsed with XmlTable.")
for table in raw_tables:
table_parser = XmlTable(XML_DECLARATION + "\n" + table)
try:
table_data = table_parser.parse()
if table_data:
parsed_tables.append(table_data)
except Exception as exc_table:
_log.error(f"Error in parsing USPTO tables: {exc_table}")
if len(parsed_tables) != len(doc.tables):
_log.error(
f"Number of referenced ({len(doc.tables)}) and parsed "
f"({len(parsed_tables)}) tables differ."
)
else:
for idx, item in enumerate(parsed_tables):
doc.tables[idx].data = item
return doc
class PatentHandler(xml.sax.handler.ContentHandler):
"""SAX ContentHandler for patent documents."""
APP_DOC_ELEMENT: Final = "patent-application-publication"
@unique
class Element(Enum):
"""Represents an element of interest in the patent application document."""
DRAWINGS = "brief-description-of-drawings", False
ABSTRACT = "subdoc-abstract", False
TITLE = "title-of-invention", True
CLAIMS = "subdoc-claims", False
CLAIM = "claim", False
CLAIM_TEXT = "claim-text", True
NUMBER = ("number", False)
PARAGRAPH = "paragraph", True
HEADING = "heading", True
STYLE_SUPERSCRIPT = "superscript", True
STYLE_SUBSCRIPT = "subscript", True
# do not store text of a table, since it can be within paragraph
TABLE = "table", False
# do not store text of a formula, since it can be within paragraph
MATH = "math-cwu", False
@override
def __new__(cls, value: str, _) -> Self:
obj = object.__new__(cls)
obj._value_ = value
return obj
@override
def __init__(self, _, is_text: bool) -> None:
self.is_text: bool = is_text
@override
def __init__(self) -> None:
"""Build an instance of the patent handler."""
# Current patent being parsed
self.doc: Optional[DoclingDocument] = None
# Keep track of docling hierarchy level
self.level: LevelNumber = 1
# Keep track of docling parents by level
self.parents: dict[LevelNumber, Optional[DocItem]] = {1: None}
# Content to retain for the current patent
self.property: list[str]
self.claim: str
self.claims: list[str]
self.abstract: str
self.text: str
self._clean_data()
# To handle mathematical styling
self.style_html = HtmlEntity()
@override
def startElement(self, tag, attributes): # noqa: N802
"""Signal the start of an element.
Args:
tag: The element tag.
attributes: The element attributes.
"""
if tag == self.APP_DOC_ELEMENT:
self.doc = DoclingDocument(name="file")
self.text = ""
self._start_registered_elements(tag, attributes)
@override
def skippedEntity(self, name): # noqa: N802
"""Receive notification of a skipped entity.
HTML entities will be skipped by the parser. This method will unescape them
and add them to the text.
Args:
name: Entity name.
"""
if self.property:
elm_val = self.property[-1]
element = self.Element(elm_val)
if element.is_text:
escaped = self.style_html.get_greek_from_iso8879(f"&{name};")
unescaped = html.unescape(escaped)
if unescaped == escaped:
logging.debug("Unrecognized HTML entity: " + name)
return
if element in (
self.Element.STYLE_SUPERSCRIPT,
self.Element.STYLE_SUBSCRIPT,
):
# superscripts and subscripts need to be under text elements
if len(self.property) < 2:
return
parent_val = self.property[-2]
parent = self.Element(parent_val)
if parent.is_text:
self.text += self._apply_style(unescaped, elm_val)
else:
self.text += unescaped
@override
def endElement(self, tag): # noqa: N802
"""Signal the end of an element.
Args:
tag: The element tag.
"""
if tag == self.APP_DOC_ELEMENT:
self._clean_data()
self._end_registered_element(tag)
@override
def characters(self, content):
"""Receive notification of character data.
Args:
content: Data reported by the handler.
"""
if self.property:
elm_val = self.property[-1]
element = self.Element(elm_val)
if element.is_text:
if element in (
self.Element.STYLE_SUPERSCRIPT,
self.Element.STYLE_SUBSCRIPT,
):
# superscripts and subscripts need to be under text elements
if len(self.property) < 2:
return
parent_val = self.property[-2]
parent = self.Element(parent_val)
if parent.is_text:
self.text += self._apply_style(content, elm_val)
else:
self.text += content
def _start_registered_elements(
self, tag: str, attributes: xml.sax.xmlreader.AttributesImpl
) -> None:
if tag in [member.value for member in self.Element]:
# special case for claims: claim lines may start before the
# previous one is closed
if (
tag == self.Element.CLAIM_TEXT.value
and self.property
and self.property[-1] == tag
and self.text.strip()
):
self.claim += " " + self.text.strip("\n")
self.text = ""
elif tag == self.Element.HEADING.value:
level_attr: str = attributes.get("lvl", "")
new_level: int = int(level_attr) if level_attr.isnumeric() else 1
max_level = min(self.parents.keys())
# increase heading level with 1 for title, if any
self.level = (
new_level + 1 if (new_level + 1) in self.parents else max_level
)
self.property.append(tag)
def _end_registered_element(self, tag: str) -> None:
if tag in [elm.value for elm in self.Element] and self.property:
current_tag = self.property.pop()
self._add_property(current_tag, self.text)
def _add_property(self, name: str, text: str) -> None:
if not name or not self.doc:
return
if name == self.Element.TITLE.value:
title = text.strip()
if title:
self.parents[self.level + 1] = self.doc.add_text(
parent=self.parents[self.level],
label=DocItemLabel.TITLE,
text=title,
)
self.level += 1
self.text = ""
elif name == self.Element.ABSTRACT.value:
abstract = self.abstract.strip()
if abstract:
heading_text = PatentHeading.ABSTRACT.value
heading_level = (
PatentHeading.ABSTRACT.level
if PatentHeading.ABSTRACT.level in self.parents
else 1
)
abstract_item = self.doc.add_heading(
heading_text,
level=heading_level,
parent=self.parents[heading_level],
)
self.doc.add_text(
label=DocItemLabel.PARAGRAPH,
text=self.abstract,
parent=abstract_item,
)
self.abstract = ""
self.text = ""
elif name == self.Element.CLAIM_TEXT.value:
if text:
self.claim += self.text.strip("\n")
self.text = ""
elif name == self.Element.CLAIM.value:
claim = self.claim.strip()
if claim:
self.claims.append(claim)
self.claim = ""
elif name == self.Element.CLAIMS.value and self.claims:
heading_text = PatentHeading.CLAIMS.value
heading_level = (
PatentHeading.CLAIMS.level
if PatentHeading.CLAIMS.level in self.parents
else 1
)
claims_item = self.doc.add_heading(
heading_text,
level=heading_level,
parent=self.parents[heading_level],
)
for text in self.claims:
self.doc.add_text(
label=DocItemLabel.PARAGRAPH, text=text, parent=claims_item
)
elif name in (
self.Element.PARAGRAPH.value,
self.Element.HEADING.value,
):
if text and self.Element.ABSTRACT.value in self.property:
self.abstract = (self.abstract + text) if self.abstract else text
elif text.strip():
text = re.sub("\\s+", " ", text).strip()
if name == self.Element.HEADING.value:
self.parents[self.level + 1] = self.doc.add_heading(
text=text,
level=self.level,
parent=self.parents[self.level],
)
self.level += 1
else:
self.doc.add_text(
label=DocItemLabel.PARAGRAPH,
text=text,
parent=self.parents[self.level],
)
self.text = ""
elif name == self.Element.TABLE.value:
# set an empty table as placeholder
empty_table = TableData(num_rows=0, num_cols=0, table_cells=[])
self.doc.add_table(
data=empty_table,
parent=self.parents[self.level],
)
def _apply_style(self, text: str, style_tag: str) -> str:
"""Apply an HTML style to text.
Args:
text: A string containing plain text.
style_tag: An HTML tag name for styling text. If the tag name is not
recognized as one of the supported styles, the method will return
the original `text`.
Returns:
A string after applying the style.
"""
formatted = html.unescape(text)
if style_tag == self.Element.STYLE_SUPERSCRIPT.value:
formatted = html.unescape(self.style_html.get_superscript(formatted))
elif style_tag == self.Element.STYLE_SUBSCRIPT.value:
formatted = html.unescape(self.style_html.get_subscript(formatted))
return formatted
def _clean_data(self):
"""Reset the variables from stream data."""
self.property = []
self.abstract = ""
self.claim = ""
self.claims = []
self.text = ""
class XmlTable:
"""Provide a table parser for xml tables in USPTO patent documents.
The OASIS Open XML Exchange Table Model can be downloaded from:
http://oasis-open.org/specs/soextblx.dtd
"""
class MinColInfoType(TypedDict):
offset: list[int]
colwidth: list[int]
class ColInfoType(MinColInfoType):
cell_range: list[int]
cell_offst: list[int]
def __init__(self, input: str) -> None:
"""Initialize the table parser with the xml content.
Args:
input: The xml content.
"""
self.max_nbr_messages = 2
self.nbr_messages = 0
self.empty_text = ""
self._soup = BeautifulSoup(input, features="xml")
def _create_tg_range(self, tgs: list[dict[str, Any]]) -> dict[int, ColInfoType]:
"""Create a unified range along the table groups.
Args:
tgs: Table group column specifications.
Returns:
Unified group column specifications.
"""
colinfo: dict[int, XmlTable.ColInfoType] = {}
if len(tgs) == 0:
return colinfo
for itg, tg in enumerate(tgs):
colinfo[itg] = {
"offset": [],
"colwidth": [],
"cell_range": [],
"cell_offst": [0],
}
offst = 0
for info in tg["colinfo"]:
cw = info["colwidth"]
cw = re.sub("pt", "", cw, flags=re.I)
cw = re.sub("mm", "", cw, flags=re.I)
try:
cw = int(cw)
except BaseException:
cw = float(cw)
colinfo[itg]["colwidth"].append(cw)
colinfo[itg]["offset"].append(offst)
offst += cw
colinfo[itg]["offset"].append(offst)
min_colinfo: XmlTable.MinColInfoType = {"offset": [], "colwidth": []}
min_colinfo["offset"] = colinfo[0]["offset"]
offset_w0 = []
for itg, col in colinfo.items():
# keep track of col with 0 width
for ic, cw in enumerate(col["colwidth"]):
if cw == 0:
offset_w0.append(col["offset"][ic])
min_colinfo["offset"] = sorted(
list(set(col["offset"] + min_colinfo["offset"]))
)
# add back the 0 width cols to offset list
offset_w0 = list(set(offset_w0))
min_colinfo["offset"] = sorted(min_colinfo["offset"] + offset_w0)
for i in range(len(min_colinfo["offset"]) - 1):
min_colinfo["colwidth"].append(
min_colinfo["offset"][i + 1] - min_colinfo["offset"][i]
)
for itg, col in colinfo.items():
i = 1
range_ = 1
for min_i in range(1, len(min_colinfo["offset"])):
min_offst = min_colinfo["offset"][min_i]
offst = col["offset"][i]
if min_offst == offst:
if (
len(col["offset"]) == i + 1
and len(min_colinfo["offset"]) > min_i + 1
):
range_ += 1
else:
col["cell_range"].append(range_)
col["cell_offst"].append(col["cell_offst"][-1] + range_)
range_ = 1
i += 1
elif min_offst < offst:
range_ += 1
else:
_log.debug("A USPTO XML table has wrong offsets.")
return {}
return colinfo
def _get_max_ncols(self, tgs_info: dict[int, ColInfoType]) -> NonNegativeInt:
"""Get the maximum number of columns across table groups.
Args:
tgs_info: Unified group column specifications.
Return:
The maximum number of columns.
"""
ncols_max = 0
for rowinfo in tgs_info.values():
ncols_max = max(ncols_max, len(rowinfo["colwidth"]))
return ncols_max
def _parse_table(self, table: Tag) -> TableData:
"""Parse the content of a table tag.
Args:
The table element.
Returns:
A docling table object.
"""
tgs_align = []
tg_secs = table.find_all("tgroup")
if tg_secs:
for tg_sec in tg_secs:
ncols = tg_sec.get("cols", None)
if ncols:
ncols = int(ncols)
tg_align = {"ncols": ncols, "colinfo": []}
cs_secs = tg_sec.find_all("colspec")
if cs_secs:
for cs_sec in cs_secs:
colname = cs_sec.get("colname", None)
colwidth = cs_sec.get("colwidth", None)
tg_align["colinfo"].append(
{"colname": colname, "colwidth": colwidth}
)
tgs_align.append(tg_align)
# create unified range along the table groups
tgs_range = self._create_tg_range(tgs_align)
# if the structure is broken, return an empty table
if not tgs_range:
dl_table = TableData(num_rows=0, num_cols=0, table_cells=[])
return dl_table
ncols_max = self._get_max_ncols(tgs_range)
# extract table data
table_data: list[TableCell] = []
i_row_global = 0
is_row_empty: bool = True
tg_secs = table.find_all("tgroup")
if tg_secs:
for itg, tg_sec in enumerate(tg_secs):
tg_range = tgs_range[itg]
row_secs = tg_sec.find_all(["row", "tr"])
if row_secs:
for row_sec in row_secs:
entry_secs = row_sec.find_all(["entry", "td"])
is_header: bool = row_sec.parent.name in ["thead"]
ncols = 0
local_row: list[TableCell] = []
is_row_empty = True
if entry_secs:
wrong_nbr_cols = False
for ientry, entry_sec in enumerate(entry_secs):
text = entry_sec.get_text().strip()
# start-end
namest = entry_sec.attrs.get("namest", None)
nameend = entry_sec.attrs.get("nameend", None)
if isinstance(namest, str) and namest.isnumeric():
namest = int(namest)
else:
namest = ientry + 1
if isinstance(nameend, str) and nameend.isnumeric():
nameend = int(nameend)
shift = 0
else:
nameend = ientry + 2
shift = 1
if nameend > len(tg_range["cell_offst"]):
wrong_nbr_cols = True
self.nbr_messages += 1
if self.nbr_messages <= self.max_nbr_messages:
_log.debug(
"USPTO table has # entries != # columns"
)
break
range_ = [
tg_range["cell_offst"][namest - 1],
tg_range["cell_offst"][nameend - 1] - shift,
]
# add row and replicate cell if needed
cell_text = text if text else self.empty_text
if cell_text != self.empty_text:
is_row_empty = False
for irep in range(range_[0], range_[1] + 1):
ncols += 1
local_row.append(
TableCell(
column_header=is_header,
text=cell_text,
start_row_offset_idx=i_row_global,
end_row_offset_idx=i_row_global + 1,
row_span=1,
start_col_offset_idx=range_[0],
end_col_offset_idx=range_[1] + 1,
col_span=range_[1] - range_[0] + 1,
)
)
if wrong_nbr_cols:
# keep empty text, not to introduce noise
local_row = []
ncols = 0
# add empty cell up to ncols_max
for irep in range(ncols, ncols_max):
local_row.append(
TableCell(
column_header=is_header,
text=self.empty_text,
start_row_offset_idx=i_row_global,
end_row_offset_idx=i_row_global + 1,
row_span=1,
start_col_offset_idx=irep,
end_col_offset_idx=irep + 1,
col_span=1,
)
)
# do not add empty rows
if not is_row_empty:
table_data.extend(local_row)
i_row_global += 1
dl_table = TableData(
num_rows=i_row_global, num_cols=ncols_max, table_cells=table_data
)
return dl_table
def parse(self) -> Optional[TableData]:
"""Parse the first table from an xml content.
Returns:
A docling table data.
"""
section = self._soup.find("table")
if section is not None:
table = self._parse_table(section)
if table.num_rows == 0 or table.num_cols == 0:
_log.warning("The parsed USPTO table is empty")
return table
else:
return None
class HtmlEntity:
"""Provide utility functions to get the HTML entities of styled characters.
This class has been developped from:
https://unicode-table.com/en/html-entities/
https://www.w3.org/TR/WD-math-970515/table03.html
"""
def __init__(self):
"""Initialize this class by loading the HTML entity dictionaries."""
self.superscript = str.maketrans(
{
"1": "¹",
"2": "²",
"3": "³",
"4": "⁴",
"5": "⁵",
"6": "⁶",
"7": "⁷",
"8": "⁸",
"9": "⁹",
"0": "⁰",
"+": "⁺",
"-": "⁻",
"−": "⁻",
"=": "⁼",
"(": "⁽",
")": "⁾",
"a": "ª",
"o": "º",
"i": "ⁱ",
"n": "ⁿ",
}
)
self.subscript = str.maketrans(
{
"1": "₁",
"2": "₂",
"3": "₃",
"4": "₄",
"5": "₅",
"6": "₆",
"7": "₇",
"8": "₈",
"9": "₉",
"0": "₀",
"+": "₊",
"-": "₋",
"−": "₋",
"=": "₌",
"(": "₍",
")": "₎",
"a": "ₐ",
"e": "ₑ",
"o": "ₒ",
"x": "ₓ",
}
)
self.mathematical_italic = str.maketrans(
{
"A": "𝐴",
"B": "𝐵",
"C": "𝐶",
"D": "𝐷",
"E": "𝐸",
"F": "𝐹",
"G": "𝐺",
"H": "𝐻",
"I": "𝐼",
"J": "𝐽",
"K": "𝐾",
"L": "𝐿",
"M": "𝑀",
"N": "𝑁",
"O": "𝑂",
"P": "𝑃",
"Q": "𝑄",
"R": "𝑅",
"S": "𝑆",
"T": "𝑇",
"U": "𝑈",
"V": "𝑉",
"W": "𝑊",
"Y": "𝑌",
"Z": "𝑍",
"a": "𝑎",
"b": "𝑏",
"c": "𝑐",
"d": "𝑑",
"e": "𝑒",
"f": "𝑓",
"g": "𝑔",
"h": "𝑕",
"i": "𝑖",
"j": "𝑗",
"k": "𝑘",
"l": "𝑙",
"m": "𝑚",
"n": "𝑛",
"o": "𝑜",
"p": "𝑝",
"q": "𝑞",
"r": "𝑟",
"s": "𝑠",
"t": "𝑡",
"u": "𝑢",
"v": "𝑣",
"w": "𝑤",
"x": "𝑥",
"y": "𝑦",
"z": "𝑧",
}
)
self.lookup_iso8879 = {
"&Agr;": "Α",
"&Bgr;": "Β",
"&Ggr;": "Γ",
"&Dgr;": "Δ",
"&Egr;": "Ε",
"&Zgr;": "Ζ",
"&EEgr;": "Η",
"&THgr;": "Θ",
"&Igr;": "Ι",
"&Kgr;": "Κ",
"&Lgr;": "Λ",
"&Mgr;": "Μ",
"&Ngr;": "Ν",
"&Xgr;": "Ξ",
"&Ogr;": "Ο",
"&Pgr;": "Π",
"&Rgr;": "Ρ",
"&Sgr;": "Σ",
"&Tgr;": "Τ",
"&Ugr;": "Υ",
"&PHgr;": "Φ",
"&KHgr;": "Χ",
"&PSgr;": "Ψ",
"&OHgr;": "Ω",
"&agr;": "α",
"&bgr;": "β",
"&ggr;": "γ",
"&dgr;": "δ",
"&egr;": "ε",
"&zgr;": "ζ",
"&eegr;": "η",
"&thgr;": "θ",
"&igr;": "ι",
"&kgr;": "κ",
"&lgr;": "λ",
"&mgr;": "μ",
"&ngr;": "ν",
"&xgr;": "ξ",
"&ogr;": "ο",
"&pgr;": "π",
"&rgr;": "ρ",
"&sgr;": "ς",
"&tgr;": "τ",
"&ugr;": "υ",
"&phgr;": "φ",
"&khgr;": "χ",
"&psgr;": "ψ",
"&ohgr;": "ω",
}
def get_superscript(self, text: str) -> str:
"""Get a text in superscript as HTML entities.
Args:
text: The text to transform.
Returns:
The text in superscript as HTML entities.
"""
return text.translate(self.superscript)
def get_subscript(self, text: str) -> str:
"""Get a text in subscript as HTML entities.
Args:
The text to transform.
Returns:
The text in subscript as HTML entities.
"""
return text.translate(self.subscript)
def get_math_italic(self, text: str) -> str:
"""Get a text in italic as HTML entities.
Args:
The text to transform.
Returns:
The text in italics as HTML entities.
"""
return text.translate(self.mathematical_italic)
def get_greek_from_iso8879(self, text: str) -> str:
"""Get an HTML entity of a greek letter in ISO 8879.
Args:
The text to transform, as an ISO 8879 entitiy.
Returns:
The HTML entity representing a greek letter. If the input text is not
supported, the original text is returned.
"""
return self.lookup_iso8879.get(text, text)
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