This snippet might work for you. I'm assuming you want no nesting of tags and the first (left most) one wins.

use Term::ANSIColor ':constants';

# Note that there is not normally an 'x' betweeh the </ and code>. I
# added that so that Perlmonks.org wouldn't parse the post incorrectly
+.
$_ = "normal <code> green <!-- yellow [red] normal --> normal </xcode>
++ normal";
$delimit{"code"} = GREEN;
$delimit{"--"} = YELLOW;
$delimit{"]"} = RED;
$RESET = RESET;

s{  (?:<code>(.+?)</x(code)>) |
    (?:(?<=\x1b)\[(.+?)(\]))  |
    (?:(<!--.+?(--)>))
 }{$delimit{$2|$4|$6}.($1|$3|$5).$RESET}egx;

print "$_\n";
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