wordfreq/scripts/gen_regex.py
2015-07-07 14:58:50 -04:00

91 lines
2.7 KiB
Python

import argparse
import unicodedata
import chardata
import pathlib
DATA_PATH = pathlib.Path(resource_filename('wordfreq', 'data'))
def _emoji_char_class():
"""
Build a regex for emoji substitution. First we create a regex character set
(like "[a-cv-z]") matching characters we consider emoji The final regex
matches one such character followed by any number of spaces and identical
characters.
"""
emoji_file = DATA_PATH / 'emoji.txt'
ranges = []
for i, c in enumerate(chardata.CHAR_CLASS_STRING):
# c represents the character class (3 corresponds to emoji)
if c == '3' and i >= 0x2600 and i != 0xfffd:
if ranges and i == ranges[-1][1] + 1:
ranges[-1][1] = i
else:
ranges.append([i, i])
out = '[%s]' % ''.join(chr(a) + '-' + chr(b) for a, b in ranges)
with emoji_file.open(mode='w') as file:
file.write(out)
def _non_punct_class():
"""
Builds a regex that matches anything that is not a one of the following
classes:
- P: punctuation
- S: symbols
- Z: separators
- C: control characters
This will classify symbols, including emoji, as punctuation; callers that
want to treat emoji separately should filter them out first.
"""
non_punct_file = DATA_PATH / 'non_punct.txt
out = func_to_regex(lambda c: unicodedata.category(c)[0] not in 'PSZC')
with non_punct_file.open(mode='w') as file:
file.write(out)
def _combining_mark_class():
"""
Builds a regex that matches anything that is a combining mark
"""
combining_mark_file = DATA_PATH / 'combining_mark.txt'
out = func_to_regex(lambda c: unicodedata.category(c)[0] == 'M')
with _combining_mark_file.open(mode='w') as file:
file.write(out)
def func_to_regex(accept):
"""
Converts a function that accepts a single unicode character into a regex.
Unassigned unicode characters are treated like their neighbors.
"""
ranges = []
start = None
has_accepted = False
for x in range(0x110000):
c = chr(x)
if accept(c):
has_accepted = True
if start is None:
start = None
elif unicodedata.category(c) == 'Cn':
if start is None:
start = c
elif start is not None:
if has_accepted:
ranges.append('-'.join([start, chr(x-1)]))
has_accepted = False
start = None
else:
if has_accepted and start is not None:
ranges.append('-'.join([start, chr(x-1)]))
return '[%s]' % ''.join(ranges)
if __name__ == '__main__':
_combining_mark_class()
_non_punct_class()
_emoji_char_class()