In Finding the right $<*digit*> capture variable Enlil mentioned $^N which I hadn't seen before. Since looking at it I'm not quite sure when one is more useful than other especially since they appear to have identical functionality. In 5.6.1 I'd use $+ in (?{...}) blocks to work with the value most recently captured by a (...) block. I suppose it might also have uses outside a regex but that appears to be pretty stilted - I'm not sure how it is useful to get the last captured value outside of a regex. Or at least the documentation describes $^N as working rather like I thought that $+ worked. So what is the difference? For reference: $+ The text matched by the last bracket of the last successful search pattern. This is useful if you don't know which one of a set of alternative patterns matched. For example:/Version: (.*)|Revision: (.*)/ && ($rev = $+); (Mnemonic: be positive and forward looking.) This variable is read-only and dynamically scoped to the current BLOCK. $^N The text matched by the used group most-recently closed (i.e. the group with the rightmost closing parenthesis) of the last successful search pattern. (Mnemonic: the (possibly) Nested parenthesis that most recently closed.) This is primarily used inside "(?{...})" blocks for examining text recently matched. For example, to effectively capture text to a variable (in addition to $1, $2, etc.), replace "(...)" with(?:(...)(?{ $var = $^N })) By setting and then using $var in this way relieves you from having to worry about exactly which numbered set of parentheses they are. This variable is dynamically scoped to the current BLOCK.
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