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Re^3: grep trouble

by davido (Archbishop)
on Apr 17, 2011 at 16:08 UTC ( #899822=note: print w/replies, xml ) Need Help??

in reply to Re^2: grep trouble
in thread grep trouble

It could be a convenience for a switch with fall-through, or along similar (but more oddball lines), possibly an implementation of Duff's Device.


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Re^4: grep trouble (body of flip-flop range)
by LanX (Bishop) on Apr 17, 2011 at 16:21 UTC

    IMHO sounds like far less than 1‰ of all CPAN modules might rely on this.


    OK found another use-case, I just recently had the need in my ORG-Parser to distinguish the range delimiters and the range "body" with a flip-flop-operator, like for ORG's "BEGIN/END"-blocks.

    This can be simplified (i.e. more DRY), if one has access to the last successful pattern:

    DB<114> for(0..99) {print if (/10/../20/ and not //)} 111213141516171819 DB<115> for(0..99) {print if (/10/../20/)} 1011121314151617181920 DB<116> for(0..99) {print if (/10/../20/ and //)} 1020

    I think that's a more frequent application, I even slightly remember seeing it in Friedl's book.

    But I'd rather prefer an explicit special varą, something like $PATTERN or $&& (in analogy to $MATCH resp. $&) .

    Cheers Rolf

    1) an special var has the advantage that the regex itself can be accessed, e.g. printed.


    for limitations see update in Re^2: Extract table from a block of text (updated)

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[choroba]: Corion A colleague has helped me. It seems the "Modification of read-only value" was caused by old Test::More version which doesn't have done_testing, plus the old bug with $@ sometimes showing a different exception
[choroba]: will upload a fixed version and see
[Corion]: choroba: Ah, OK - sounds like a really weird combination :)

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