mirror of https://github.com/python/cpython
71 lines
2.3 KiB
Python
71 lines
2.3 KiB
Python
"""Generate 10,000 unique examples for the Levenshtein short-circuit tests."""
|
|
|
|
import argparse
|
|
from functools import lru_cache
|
|
import json
|
|
import os.path
|
|
from random import choices, randrange
|
|
|
|
|
|
# This should be in sync with Lib/traceback.py. It's not importing those values
|
|
# because this script is being executed by PYTHON_FOR_REGEN and not by the in-tree
|
|
# build of Python.
|
|
_MOVE_COST = 2
|
|
_CASE_COST = 1
|
|
|
|
|
|
def _substitution_cost(ch_a, ch_b):
|
|
if ch_a == ch_b:
|
|
return 0
|
|
if ch_a.lower() == ch_b.lower():
|
|
return _CASE_COST
|
|
return _MOVE_COST
|
|
|
|
|
|
@lru_cache(None)
|
|
def levenshtein(a, b):
|
|
if not a or not b:
|
|
return (len(a) + len(b)) * _MOVE_COST
|
|
option1 = levenshtein(a[:-1], b[:-1]) + _substitution_cost(a[-1], b[-1])
|
|
option2 = levenshtein(a[:-1], b) + _MOVE_COST
|
|
option3 = levenshtein(a, b[:-1]) + _MOVE_COST
|
|
return min(option1, option2, option3)
|
|
|
|
|
|
def main():
|
|
parser = argparse.ArgumentParser(description=__doc__)
|
|
parser.add_argument('output_path', metavar='FILE', type=str)
|
|
parser.add_argument('--overwrite', dest='overwrite', action='store_const',
|
|
const=True, default=False,
|
|
help='overwrite an existing test file')
|
|
|
|
args = parser.parse_args()
|
|
output_path = os.path.realpath(args.output_path)
|
|
if not args.overwrite and os.path.isfile(output_path):
|
|
print(f"{output_path} already exists, skipping regeneration.")
|
|
print(
|
|
"To force, add --overwrite to the invocation of this tool or"
|
|
" delete the existing file."
|
|
)
|
|
return
|
|
|
|
examples = set()
|
|
# Create a lot of non-empty examples, which should end up with a Gauss-like
|
|
# distribution for even costs (moves) and odd costs (case substitutions).
|
|
while len(examples) < 9990:
|
|
a = ''.join(choices("abcABC", k=randrange(1, 10)))
|
|
b = ''.join(choices("abcABC", k=randrange(1, 10)))
|
|
expected = levenshtein(a, b)
|
|
examples.add((a, b, expected))
|
|
# Create one empty case each for strings between 0 and 9 in length.
|
|
for i in range(10):
|
|
b = ''.join(choices("abcABC", k=i))
|
|
expected = levenshtein("", b)
|
|
examples.add(("", b, expected))
|
|
with open(output_path, "w") as f:
|
|
json.dump(sorted(examples), f, indent=2)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|