themage,
Your benchmark disagrees with mine (with x 20 and x 200). Additionally, I think you should re-read perlre with regards to what /o does.

I am sure diotalevi will improve upon my explanation but in a nutshell, /o is an old optimization predating qr//. If you needed to interpolate a variable inside a regex such as /$regex/ but knew that $regex would never change, the flag would tell perl to only compile the regex once. In fact, if you broke your promise and changed $regex then it would still not recompile it leading to buggy code. Then came along qr// and improved things greatly (see /o is dead, long live qr//!).

Since you are not using a variable in your interpolation - the /o is having no effect.

See also this regarding how current perl's optimize regex compiling. Unfortunately I couldn't seem to find this in any perldelta from 5.6.1 to 5.9.4 which makes me suspicious so I posted Questions concerning /o regex modifier.

Cheers - L~R

In reply to Re^3: Splitting a string to chunks by Limbic~Region
in thread Splitting a string to chunks by spurperl

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