cpython/Tools/build/generate_sre_constants.py

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#! /usr/bin/env python3
# This script generates Modules/_sre/sre_constants.h from Lib/re/_constants.py.
SCRIPT_NAME = 'Tools/build/generate_sre_constants.py'
def update_file(file, content):
try:
with open(file, 'r') as fobj:
if fobj.read() == content:
return False
except (OSError, ValueError):
pass
with open(file, 'w') as fobj:
fobj.write(content)
return True
sre_constants_header = f"""\
/*
* Secret Labs' Regular Expression Engine
*
* regular expression matching engine
*
* Auto-generated by {SCRIPT_NAME} from
* Lib/re/_constants.py.
*
* Copyright (c) 1997-2001 by Secret Labs AB. All rights reserved.
*
* See the sre.c file for information on usage and redistribution.
*/
"""
def main(
infile="Lib/re/_constants.py",
outfile_constants="Modules/_sre/sre_constants.h",
outfile_targets="Modules/_sre/sre_targets.h",
):
ns = {}
with open(infile) as fp:
code = fp.read()
exec(code, ns)
def dump(d, prefix):
items = sorted(d)
for item in items:
yield "#define %s_%s %d\n" % (prefix, item, item)
def dump2(d, prefix):
items = [(value, name) for name, value in d.items()
if name.startswith(prefix)]
for value, name in sorted(items):
yield "#define %s %d\n" % (name, value)
def dump_gotos(d, prefix):
for i, item in enumerate(sorted(d)):
assert i == item
yield f" &&{prefix}_{item},\n"
content = [sre_constants_header]
content.append("#define SRE_MAGIC %d\n" % ns["MAGIC"])
content.extend(dump(ns["OPCODES"], "SRE_OP"))
content.extend(dump(ns["ATCODES"], "SRE"))
content.extend(dump(ns["CHCODES"], "SRE"))
content.extend(dump2(ns, "SRE_FLAG_"))
content.extend(dump2(ns, "SRE_INFO_"))
update_file(outfile_constants, ''.join(content))
content = [sre_constants_header]
content.append(f"static void *sre_targets[{len(ns['OPCODES'])}] = {{\n")
content.extend(dump_gotos(ns["OPCODES"], "TARGET_SRE_OP"))
content.append("};\n")
update_file(outfile_targets, ''.join(content))
if __name__ == '__main__':
import sys
main(*sys.argv[1:])