go/regexp at 82bf12902f2abecdbe2cb5fa38299ac70cf9c67e - go

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History

Ludi Rehak 82bf12902f regexp/syntax: test for lowercase letters first in IsWordChar

Lowercase letters occur more frequently than uppercase letters
in English text.  In IsWordChar, evaluate the most common case
(lowercase letters) first to minimize the expected value of its
execution time. Code clarity does not suffer by rearranging the
order of the checks.

Add a benchmark on a sentence demonstrating the performance
improvement.

name           old time/op  new time/op  delta
IsWordChar-10   122ns ± 0%   114ns ± 1%  -6.68%  (p=0.000 n=8+10)

Change-Id: Ieee8126a4bd8ee8703905b4f75724623029f6fa2
Reviewed-on: https://go-review.googlesource.com/c/go/+/404100
Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: thepudds <thepudds1460@gmail.com>

2023-03-14 04:39:42 +00:00

syntax

regexp/syntax: test for lowercase letters first in IsWordChar

2023-03-14 04:39:42 +00:00

testdata

regexp: fix repeat of preferred empty match

2021-05-13 14:52:20 +00:00

all_test.go

regexp: add ErrLarge error

2022-11-02 18:15:21 +00:00

backtrack.go

regexp: avoid copying each instruction executed