"... a change from my $delim = '([{<'; to my $delim = '(-[{<'; may not be readily apparent ..."

I find it hard to believe that you think that range of 52 characters "may not be readily apparent". 

$ perl -E 'say "@{[map chr, ord q{(} .. ord q{[}]}"'
( ) * + , - . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ? @ A B C D E F G H I J 
+K L M N O P Q R S T U V W X Y Z [

[download]

The OP hadn't asked for a hyphen to take on a parenthetical function; however, if that was wanted, the correct way to write it would be: 

my $delim = '([{<-';

[download]

And still nothing needs to be escaped.

What you've contrived as an example is a novice mistake. It's a good mistake to learn from. I'm sure I made that mistake a quarter of a century ago; found out what I did wrong; and, didn't do it again.

Defensive programming is all well and good when dealing with data from an unknown or untrusted source. When the data is just four characters you've written yourself; defensive programming is overkill.

— Ken

In reply to Re^5: bracket processing by kcott
in thread bracket processing by rajaman

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