# 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 functools import lru_cache
from lark import Token, Transformer
from lark.exceptions import UnexpectedInput
from lark.lark import Lark
from lark.tree import Tree
from padrick.Model.TemplatedIndexGrammar import TemplatedIdxToStringTransformer, TemplatedIdxEvaluator, \
templated_index_grammar
expression_language = r"""
?start: identifier
identifier: (UNDERSCORE|LETTER) (UNDERSCORE|LETTER|DIGIT|idx_template)*
// It would be cleaner to import those rules from Lark common grammar but this prevents pyoxidized binary creation
// due to stupid package resource importing scheme used in lark
// Basic terminals for common use
//
// Numbers
//
DIGIT: "0".."9"
HEXDIGIT: "a".."f"|"A".."F"|DIGIT
INT: DIGIT+
SIGNED_INT: ["+"|"-"] INT
DECIMAL: INT "." INT? | "." INT
// float = /-?\d+(\.\d+)?([eE][+-]?\d+)?/
_EXP: ("e"|"E") SIGNED_INT
FLOAT: INT _EXP | DECIMAL _EXP?
SIGNED_FLOAT: ["+"|"-"] FLOAT
NUMBER: FLOAT | INT
SIGNED_NUMBER: ["+"|"-"] NUMBER
//
// Strings
//
_STRING_INNER: /.*?/
_STRING_ESC_INNER: _STRING_INNER /(?<!\\)(\\\\)*?/
ESCAPED_STRING : "\"" _STRING_ESC_INNER "\""
//
// Names (Variables)
//
LCASE_LETTER: "a".."z"
UCASE_LETTER: "A".."Z"
LETTER: UCASE_LETTER | LCASE_LETTER
WORD: LETTER+
CNAME: ("_"|LETTER) ("_"|LETTER|DIGIT)*
//
// Whitespace
//
WS_INLINE: (" "|/\t/)+
WS: /[ \t\f\r\n]/+
CR : /\r/
LF : /\n/
NEWLINE: (CR? LF)+
// Comments
SH_COMMENT: /#[^\n]*/
CPP_COMMENT: /\/\/[^\n]*/
C_COMMENT: "/*" /(.|\n)*?/ "*/"
SQL_COMMENT: /--[^\n]*/
"""
templated_identifier_parser = Lark(expression_language + templated_index_grammar, parser="lalr")
# class TokenMerger(Transformer):
# def identifier(self, children):
# merged_children = []
# tokens_to_merge = []
# for child in children:
# if isinstance(child, str):
# tokens_to_merge.append(child)
# else:
# if tokens_to_merge:
# merged_children.append("".join(tokens_to_merge))
# tokens_to_merge = []
# merged_children.append(child)
# if tokens_to_merge:
# merged_children.append("".join(tokens_to_merge))
# if len(merged_children)
#@lru_cache()
[docs]def parse_expression(expression: str):
return templated_identifier_parser.parse(str(expression))
[docs]class TemplatedIdentifierType(str):
def __init__(self, expression: str):
super().__init__()
if expression == None:
self._ast = ""
else:
try:
self._ast = parse_expression(str(self))
except UnexpectedInput as e:
raise ValueError("Illegal identifier: "+str(e))
@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 (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 = TemplatedIdentifierType.validate("test_{i+2:3d}")
print(expr.evaluate_template(32))