# Copyright 2017 Zdenek Kraus <zdenek.kraus@gmail.com>
#
# 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 re
REFORMAT_PATTERN = '(?:%{([a-zA-Z0-9_]+)(?:\|([^}|]*))?(?:\|([^}|]*))?})|([^%]+|%)'
"""Regular expression searches for reformat notation "%{NAME [| POSITIVE] [| NEGATIVE]}", and other strings"""
REFORMAT_REX = re.compile(REFORMAT_PATTERN)
def get_subs_list(pattern):
items = REFORMAT_REX.findall(pattern)
# (var_name, positive_pattern, negative_pattern, plain_string)
return items
def reformat(pattern, data, default=''):
items = get_subs_list(pattern)
result = pattern
if data is None:
return pattern
if not isinstance(data, dict):
raise TypeError('input data must be dict or None')
out_list = []
for item, pt, ptn, string in items:
# plain string do not reformat
if string:
out_list.append(string)
# pattern do reformat
else:
present = item in data
i_data = str(data.get(item, default))
if present:
if pt:
try:
tmp = pt % (i_data,) # format positive pattern
except TypeError:
tmp = pt # pattern cannot be formatted, it will become output
else:
tmp = i_data # no included pattern available, just plain replace
elif not present and ptn:
try:
tmp = ptn % (i_data,) # format negative pattern
except TypeError:
tmp = ptn # pattern cannot be formatted, it will become output
else:
tmp = ''
out_list.append(tmp)
result = "".join(out_list)
return result
