Can anyone tell me where I can find additional information and background on the newer regular expression formats? Particularly I see a lot of examples of help being provided with the liberal useage of the ? question mark in the expressions. I always thought ? was for making 0 or 1 of something, or for marking a quantifier as "nongreedy", but I am not familiar with these other uses. Also is the use of $1, $2... being obsoleted styllistically for this new ? thing?

In reply to more info about regex updates by raybies

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