Before deferring re.compile, can we make it faster?
I profiled `import string` and small optimization can make it 2x faster!
(but it's not backward compatible)
Before optimize:
import time: self [us] | cumulative | imported package
import time: 2339 | 9623 | string
string module took about 2.3 ms to import.
I found:
* RegexFlag.__and__ and __new__ is called very often.
* _optimize_charset is slow, because re.UNICODE | re.IGNORECASE
diff --git a/Lib/sre_compile.py b/Lib/sre_compile.py
index 144620c6d1..7c662247d4 100644
--- a/Lib/sre_compile.py
+++ b/Lib/sre_compile.py
@@ -582,7 +582,7 @@ def isstring(obj):
def _code(p, flags):
- flags = p.pattern.flags | flags
+ flags = int(p.pattern.flags) | int(flags)
code = []
# compile info block
diff --git a/Lib/string.py b/Lib/string.py
index b46e60c38f..fedd92246d 100644
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -81,7 +81,7 @@ class Template(metaclass=_TemplateMetaclass):
delimiter = '$'
idpattern = r'[_a-z][_a-z0-9]*'
braceidpattern = None
- flags = _re.IGNORECASE
+ flags = _re.IGNORECASE | _re.ASCII
def __init__(self, template):
self.template = template
patched:
import time: 1191 | 8479 | string
Of course, this patch is not backward compatible. [a-z] doesn't match with
'ı' or 'ſ' anymore.
But who cares?
(in sre_compile.py)
# LATIN SMALL LETTER I, LATIN SMALL LETTER DOTLESS I
(0x69, 0x131), # iı
# LATIN SMALL LETTER S, LATIN SMALL LETTER LONG S
(0x73, 0x17f), # sſ
There are some other `re.I(GNORECASE)` options in stdlib. I'll check them.
More optimization can be done with implementing sre_parse and sre_compile
in C.
But I have no time for it in this year.
Regards,
--
Inada Naoki <songofaca...@gmail.com>
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