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bpo-433030: Add support of atomic grouping in regular expressions (GH-31982)

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* Atomic grouping: (?>...).
* Possessive quantifiers: x++, x*+, x?+, x{m,n}+.
  Equivalent to (?>x+), (?>x*), (?>x?), (?>x{m,n}).

Co-authored-by: Jeffrey C. Jacobs <timehorse@users.sourceforge.net>
This commit is contained in:
Serhiy Storchaka 2022-03-21 18:28:22 +02:00 • committed by GitHub
parent 2bde6827ea
commit 345b390ed6
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GPG key ID: 4AEE18F83AFDEB23
11 changed files with 593 additions and 92 deletions
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38
Lib/sre_compile.py
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@ -17,11 +17,16 @@ from sre_constants import *
assert _sre.MAGIC == MAGIC, "SRE module mismatch"
_LITERAL_CODES = {LITERAL, NOT_LITERAL}
_REPEATING_CODES = {REPEAT, MIN_REPEAT, MAX_REPEAT}
_SUCCESS_CODES = {SUCCESS, FAILURE}
_ASSERT_CODES = {ASSERT, ASSERT_NOT}
_UNIT_CODES = _LITERAL_CODES | {ANY, IN}
_REPEATING_CODES = {
MIN_REPEAT: (REPEAT, MIN_UNTIL, MIN_REPEAT_ONE),
MAX_REPEAT: (REPEAT, MAX_UNTIL, REPEAT_ONE),
POSSESSIVE_REPEAT: (POSSESSIVE_REPEAT, SUCCESS, POSSESSIVE_REPEAT_ONE),
}
# Sets of lowercase characters which have the same uppercase.
_equivalences = (
# LATIN SMALL LETTER I, LATIN SMALL LETTER DOTLESS I
@ -138,10 +143,7 @@ def _compile(code, pattern, flags):
if flags & SRE_FLAG_TEMPLATE:
raise error("internal: unsupported template operator %r" % (op,))
if _simple(av[2]):
if op is MAX_REPEAT:
emit(REPEAT_ONE)
else:
emit(MIN_REPEAT_ONE)
emit(REPEATING_CODES[op][2])
skip = _len(code); emit(0)
emit(av[0])
emit(av[1])
@ -149,16 +151,13 @@ def _compile(code, pattern, flags):
emit(SUCCESS)
code[skip] = _len(code) - skip
else:
emit(REPEAT)
emit(REPEATING_CODES[op][0])
skip = _len(code); emit(0)
emit(av[0])
emit(av[1])
_compile(code, av[2], flags)
code[skip] = _len(code) - skip
if op is MAX_REPEAT:
emit(MAX_UNTIL)
else:
emit(MIN_UNTIL)
emit(REPEATING_CODES[op][1])
elif op is SUBPATTERN:
group, add_flags, del_flags, p = av
if group:
@ -169,6 +168,17 @@ def _compile(code, pattern, flags):
if group:
emit(MARK)
emit((group-1)*2+1)
elif op is ATOMIC_GROUP:
# Atomic Groups are handled by starting with an Atomic
# Group op code, then putting in the atomic group pattern
# and finally a success op code to tell any repeat
# operations within the Atomic Group to stop eating and
# pop their stack if they reach it
emit(ATOMIC_GROUP)
skip = _len(code); emit(0)
_compile(code, av, flags)
emit(SUCCESS)
code[skip] = _len(code) - skip
elif op in SUCCESS_CODES:
emit(op)
elif op in ASSERT_CODES:
@ -709,7 +719,8 @@ def dis(code):
else:
print_(FAILURE)
i += 1
elif op in (REPEAT, REPEAT_ONE, MIN_REPEAT_ONE):
elif op in (REPEAT, REPEAT_ONE, MIN_REPEAT_ONE,
POSSESSIVE_REPEAT, POSSESSIVE_REPEAT_ONE):
skip, min, max = code[i: i+3]
if max == MAXREPEAT:
max = 'MAXREPEAT'
@ -725,6 +736,11 @@ def dis(code):
print_(op, skip, arg, to=i+skip)
dis_(i+2, i+skip)
i += skip
elif op is ATOMIC_GROUP:
skip = code[i]
print_(op, skip, to=i+skip)
dis_(i+1, i+skip)
i += skip
elif op is INFO:
skip, flags, min, max = code[i: i+4]
if max == MAXREPEAT: