Re^2: A regex that only matches at offset that are multiples of a given N?

[7stud]

in reply to Re: A regex that only matches at offset that are multiples of a given N?
in thread A regex that only matches at offset that are multiples of a given N?

In this regex:

fred
(?              
    (?{ pos % 4 != 0 })
    (?!)
)
(....)

What does this construct do:

(?stuff)

I can't find anything about that in perlre.

Edit: Ah, the boolean test finally clued me in:

(?(condition)yes-pattern)

[smls]

I can't find anything about that in perlre.

perlre is not exactly optimized for quickly finding out the meaning of a specific regex construct.

Use perlreref for that.