# Copyright NeMo (https://github.com/NVIDIA/NeMo). All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import pynini
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from fun_text_processing.text_normalization.en.graph_utils import GraphFst
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from pynini.lib import pynutil
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class FractionFst(GraphFst):
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"""
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Finite state transducer for classifying fraction
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"23 4/6" ->
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fraction { integer: "drei und zwanzig" numerator: "vier" denominator: "sechs" preserve_order: true }
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Args:
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cardinal: cardinal GraphFst
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deterministic: if True will provide a single transduction option,
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for False multiple transduction are generated (used for audio-based normalization)
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"""
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def __init__(self, cardinal, deterministic: bool = True):
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super().__init__(name="fraction", kind="classify", deterministic=deterministic)
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cardinal_graph = cardinal.graph
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self.optional_graph_negative = pynini.closure(
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pynutil.insert("negative: ") + pynini.cross("-", "\"true\" "), 0, 1
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)
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self.integer = pynutil.insert("integer_part: \"") + cardinal_graph + pynutil.insert("\"")
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self.numerator = (
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pynutil.insert("numerator: \"") + cardinal_graph + pynini.cross(pynini.union("/", " / "), "\" ")
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)
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self.denominator = pynutil.insert("denominator: \"") + cardinal_graph + pynutil.insert("\"")
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self.graph = (
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self.optional_graph_negative
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+ pynini.closure(self.integer + pynini.accep(" "), 0, 1)
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+ self.numerator
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+ self.denominator
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)
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graph = self.graph + pynutil.insert(" preserve_order: true")
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final_graph = self.add_tokens(graph)
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self.fst = final_graph.optimize()
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