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# Copyright (c) 2015 Mirantis, Inc.
#
# 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.
import codecs
import re
from yaql.language import exceptions
NEVER_MATCHING_RE = '(?!x)x'
ESCAPE_SEQUENCE_RE = re.compile(r'''
( \\U........ # 8-digit hex escapes
| \\u.... # 4-digit hex escapes
| \\x.. # 2-digit hex escapes
| \\[0-7]{1,3} # Octal escapes
| \\N\{[^}]+\} # Unicode characters by name
| \\[\\'"abfnrtv] # Single-character escapes
)''', re.UNICODE | re.VERBOSE)
def decode_escapes(s):
def decode_match(match):
return codecs.decode(match.group(0), 'unicode-escape')
return ESCAPE_SEQUENCE_RE.sub(decode_match, s)
# noinspection PyPep8Naming
class Lexer:
t_ignore = ' \t\r\n'
literals = '()],}'
keywords = {
'true': 'TRUE',
'false': 'FALSE',
'null': 'NULL'
}
keyword_to_val = {
'TRUE': True,
'FALSE': False,
'NULL': None
}
def __init__(self, yaql_operators):
self._operators_table = yaql_operators.operators
self.tokens = [
'KEYWORD_STRING',
'QUOTED_STRING',
'NUMBER',
'FUNC',
'DOLLAR',
'INDEXER',
'MAPPING',
'MAP'
] + list(self.keywords.values())
for op_symbol, op_record in self._operators_table.items():
if op_symbol in ('[]', '{}'):
continue
lexem_name = op_record[2]
setattr(self, 't_' + lexem_name, re.escape(op_symbol))
self.tokens.append(lexem_name)
self.t_MAPPING = re.escape(yaql_operators.name_value_op) \
if yaql_operators.name_value_op else NEVER_MATCHING_RE
self.t_INDEXER = '\\[' \
if '[]' in self._operators_table else NEVER_MATCHING_RE
self.t_MAP = '{' \
if '{}' in self._operators_table else NEVER_MATCHING_RE
@staticmethod
def t_DOLLAR(t):
"""
\\$\\w*
"""
return t
@staticmethod
def t_NUMBER(t):
"""
\\b\\d+(\\.?\\d+)?\\b
"""
if '.' in t.value:
t.value = float(t.value)
else:
t.value = int(t.value)
return t
@staticmethod
def t_FUNC(t):
"""
\\b[^\\W\\d]\\w*\\(
"""
val = t.value[:-1]
t.value = val
return t
def t_KEYWORD_STRING(self, t):
"""
(?!__)\\b[^\\W\\d]\\w*\\b
"""
if t.value in self._operators_table:
t.type = self._operators_table[t.value][2]
else:
t.type = self.keywords.get(t.value, 'KEYWORD_STRING')
t.value = self.keyword_to_val.get(t.type, t.value)
return t
@staticmethod
def t_QUOTED_STRING(t):
"""
'([^'\\\\]|\\\\.)*'
"""
t.value = decode_escapes(t.value[1:-1])
return t
@staticmethod
def t_DOUBLE_QUOTED_STRING(t):
"""
"([^"\\\\]|\\\\.)*"
"""
t.value = decode_escapes(t.value[1:-1])
t.type = 'QUOTED_STRING'
return t
@staticmethod
def t_QUOTED_VERBATIM_STRING(t):
"""
`([^`\\\\]|\\\\.)*`
"""
t.value = t.value[1:-1].replace('\\`', '`')
t.type = 'QUOTED_STRING'
return t
@staticmethod
def t_error(t):
raise exceptions.YaqlLexicalException(t.value[0], t.lexpos)
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