PHP regex delimiter, what's the point? -

Why do PHP regexes surrounding the delimiter? It seems that it would be more obvious that any patent modifier was passed as a parameter in whatever function was being used.

As mentioned in a comment, the underlying library does not require flags To be passed as part of regexp - in fact, the extension must be separated and separated as a separate argument.

It appears that the original implementation was trying to make it like grep / sed / awk / perl / etc so that it becomes more familiar for programmers coming from those devices.