Source code for en_us_normalization.production.verbalize.roman

Copyright 2022 Balacoon
Copyright (c) 2021, NVIDIA CORPORATION.  All rights reserved.
Copyright 2015 and onwards Google, Inc.

Verbalizes roman numbers

import pynini
from en_us_normalization.production.verbalize.cardinal import CardinalFst
from en_us_normalization.production.verbalize.ordinal import OrdinalFst
from pynini.lib import pynutil

from learn_to_normalize.grammar_utils.base_fst import BaseFst
from learn_to_normalize.grammar_utils.shortcuts import NOT_BAR, insert_space

[docs]class RomanFst(BaseFst): """ Finite state transducer for verbalizing roman numerals. By default, romans are expanded as cardinals. But for some prefixes, they should be expanded as ordinals (for ex. georg the first). This distinction happens during tagging, verbalizer just applies expansion depending on the field name (count or order). Prefixes are coming from pre-defined list and do not require verbalization. Examples of input/output strings: - roman|count:25| -> twenty five - roman|prefix:chapter|count:26| -> chapter twenty six - roman|prefix:george|order:1| -> george the first """
[docs] def __init__(self, cardinal: CardinalFst = None, ordinal: OrdinalFst = None): """ constructor for roman numerals verbalizer Parameters ---------- cardinal: CardinalFst reusing cardinal verbalizer, this is the one mostly applied ordinal: OrdinalFst reusing ordinal verbalizer. applied only with specific prefixes """ super().__init__(name="roman") if cardinal is None: cardinal = CardinalFst() if ordinal is None: ordinal = OrdinalFst(cardinal) prefix = ( pynutil.delete("prefix:") + pynini.closure(NOT_BAR) + pynutil.delete("|") + insert_space ) # prefix is optional optional_prefix = pynini.closure(prefix, 0, 1) cardinal_roman = ( pynutil.delete("count:") + cardinal.get_cardinal_expanding_fst() ) ordinal_roman = ( pynutil.insert("the ") + pynutil.delete("order:") + ordinal.get_ordinal_expanding_fst() ) graph = cardinal_roman | ordinal_roman graph = optional_prefix + graph + pynutil.delete("|") self._single_fst = self.delete_tokens(graph).optimize()