45 lines
1.4 KiB
Python
45 lines
1.4 KiB
Python
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# coding=utf-8
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"""Helpers for working with fstrings (python3.6+)."""
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# Copyright 2019 Google LLC
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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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# https://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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from __future__ import absolute_import
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from __future__ import division
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from __future__ import print_function
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import ast
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_FSTRING_VAL_PLACEHOLDER = '__pasta_fstring_val_{index}__'
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def get_formatted_values(joined_str):
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"""Get all FormattedValues from a JoinedStr, in order."""
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return [v for v in joined_str.values if isinstance(v, ast.FormattedValue)]
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def placeholder(val_index):
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"""Get the placeholder token for a FormattedValue in an fstring."""
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return _FSTRING_VAL_PLACEHOLDER.format(index=val_index)
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def perform_replacements(fstr, values):
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"""Replace placeholders in an fstring with subexpressions."""
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for i, value in enumerate(values):
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fstr = fstr.replace(_wrap(placeholder(i)), _wrap(value))
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return fstr
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def _wrap(s):
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return '{%s}' % s
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