Starting with 
use constant DLE => 0x10;

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I would like to contruct a regular expression that matches when the first charater *is* a DLE and the second character is anything but a DLE. I'm having trouble, because I doubt that variables are interpolated in a character class: 
my $dle = chr(DLE);
$msg =~ /\A$dle[^$dle]/;

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I'd be interested in any alternatives, as long as the DLE is defined symbolically and not "hard coded". Thanks !

In reply to Interpolation in character class by Anonymous Monk

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