From perldoc perlre: 
x   Extend your pattern's legibility by permitting
           whitespace and comments.
...
...
The /x modifier itself needs a little 
more explanation. It tells the regular 
expression parser to ignore
whitespace that is not backslashed or 
within a character class. You can use 
this modifier to break
up your regular expression into (slightly) 
more readable parts.

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It *can* be inferred from here that /x applies only to the first part of s///, but it's not really conclusive. Perhaps this can be clarified with a brief note.

In reply to Re: Space and the /x modifier by spurperl
in thread Space and the /x modifier by Django

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