# Manuel Eggimann <meggimann@iis.ee.ethz.ch>
#
# Copyright (C) 2021-2022 ETH Zürich
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from copy import deepcopy
from lark import Token
from lark.exceptions import UnexpectedInput
from lark.lark import Lark
from lark.tree import Tree
from lark.visitors import Transformer, v_args
from padrick.Model.TemplatedIndexGrammar import TemplatedIdxToStringTransformer, TemplatedIdxEvaluator, templated_index_grammar
grammar = r"""
?start: (idx_template | TEXT)*
TEXT: /[^{}]+/
"""
templated_string_parser = Lark(grammar + templated_index_grammar, parser='lalr')
[docs]class TemplatedStringType(str):
_expression: str
ast: Tree
def __init__(self, expression: str):
super().__init__()
if expression == None:
expression = ""
self._ast = templated_string_parser.parse(str(expression))
@property
def identifier(self) -> str:
return str(self)
@property
def ast(self):
return self._ast
[docs] def evaluate_template(self, i):
if not isinstance(self.ast, Token):
return TemplatedStringType((TemplatedIdxEvaluator(i) * TemplatedIdxToStringTransformer()).transform(self.ast))
else:
return self
@classmethod
def __get_validators__(cls):
yield cls.validate
[docs] @classmethod
def validate(cls, v):
try:
expr = cls(v)
except UnexpectedInput as e:
raise ValueError(f'Error while parsing expression: {v}.\nError {str(e)}')
return expr
def __repr__(self):
return self.__str__()
if __name__ == "__main__":
expr = TemplatedStringType.validate("This is a test <i+10> !!!")
print(expr.evaluate_template(42))