s/A/B/ and s/B/C/ but don't want A -> C (was: FAQ 6.4 I put a regular expression into $/ but it didn't work. What's wrong?)

On Thu, 27 Dec 2007 21:35:11 +0000 Ben Morrow <ben@xxxxxxxxxxxx> wrote:

BM> Quoth PerlFAQ Server <brian@xxxxxxxxxxxxxx>:

6.4: I put a regular expression into $/ but it didn't work. What's wrong?

Up to Perl 5.8.0, $/ has to be a string. This may change in 5.10, but
don't get your hopes up. Until then, you can use these examples if you

BM> s/8/10/; s/10/12/;

You want that backwards :)

Actually, I've often run into the need for parallel edits like this,
where you want to s/A/B/ and s/B/C but you don't want A to become C.
With complex operations or operations you don't know in advance, proper
ordering becomes impossible. I usually handle it with function calls:
s/[ABC]/replacement(\1)/e or something like that. Is there a better
approach anyone can recommend?

Thanks
Ted
.

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