I was going to suggest better definitions of $octet (one using pure regexes and one using a code assertion), but I'll refrain from that after having read your last paragraph. ;-)

And, BTW, to the OP: what you're looking for is not called a character class (but this has been pointed out already).

In reply to Re^2: Defining your own regex character class by Laurent_R
in thread Defining your own regex character class by igoryonya

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