[英]What's the maximum number of numbered regex captures?
I'm maintaining some code that reads values over a serial radio and unpacks them into Perl data structures: 我正在维护一些通过串行无线电读取值的代码,并将它们解压缩到Perl数据结构中:
# Don't yell at me, I didn't write this
if ($command_string =~
/^.(.)(.).(..)(.)(..)(.)(....)(....)(....)(....)
(..)(..)(.)(.)(.)(.)(..)(..)(..)(..)(..)(..)(.)(.).......
(.)........(.)(.).*/sx) {
$config->{sequence} = hex(unpack('H2', $1));
$config->{radio_id} = hex(unpack('H2', $2));
...
$config->{radio_type} = hex(unpack('H2', $26));
$config->{radio_channel} = hex(unpack('H2', $27));
}
This unwieldy capturing regex made me wonder: what's the upper bound on numbered capture variables in Perl? 这个笨重的捕获正则表达式让我想知道:Perl中编号捕获变量的上限是什么? Does it go all the way up to
$MAXINT
? 它会一直到
$MAXINT
吗?
This script works up to at least $N=5000000
. 此脚本至少
$N=5000000
。 After that, it runs out of memory. 之后,它耗尽了内存。
$N = $ARGV[0] || 5000;
$q = '(.)' x $N;
$regex = qr/$q/;
("x" x $N) =~ $regex;
print eval "\$$N";
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