Also Regexp::Common would meet your needs.
use Regexp::Common;
my $parens = qr/$RE{balanced}{-parens=>'()'}/;

# ...

# my fix
$theParam =~ s/([A-Z]+)($parens)/&doFunc($1,$2)/geo;

__END__
Using your script, it will print 
Example 1: func A returns <(func B returns <(2)>)>
Example 2: func A returns <(func B returns <(2)>+func C returns <(func
+ D returns <()>)>)>

[download]

In reply to Re: How to find matching pairs by rnahi
in thread How to find matching pairs by Anonymous Monk

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