Oniguruma.OptionsSourceRegex options.
An option. The phantom type parameter indicates whether it is compile-time or search-time.
Combines options.
This operation is:
(x <+> y) <+> z = x <+> (y <+> z)x <+> y = y <+> xx <+> x = xRepresents compile-time options.
Represents search-time options.