Use a regex that calls itself. 
#!/usr/bin/perl

my $qr;
$qr = qr!(?:\<(?:(?>[^\<\>]+)|(??{$qr}))*\>)!;

$_  = "<<a> a> a <a>";
s/($qr)/\U$1/g;
print;

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Boris

In reply to Re: I don't remember regex seeming this hard before by borisz
in thread I don't remember regex seeming this hard before by danderson

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