I'm not at all sure about using _ as the delimiter, but everything else I tried was altogether too messy.

Just so you know, they curlies dont need to be escaped here. And this in turn means the traditional regex delimiter looks fine

s/{.*?}/{$sub[$n++]}/g;
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As the open curlie starts at the BOS it _can't_ have its meta meaning, and thus needs no escape. Dont worry, as I found out ages ago, perl is quite smart about delimiters in regexes. For instance

s{{.*?}}{{$sub[$n++]}}g;
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also works just fine, even if it looks a mess.

Anyway, just my $0.02
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demerphq

_{<Elian> And I do take a kind of perverse pleasure in having an OO assembly language...}