Re: What are these hex character classes?

[Kenosis]

From Prelre:

\x{}, \x00  character whose ordinal is the given hexadecimal number

The \x denotes the beginning of a hexadecimal value.

• \x{A} - Unicode Character 'LINE FEED (LF)'
• \x{B} - Unicode Character 'LINE TABULATION'
• \x{C} - Unicode Character 'FORM FEED (FF)'
• \x{D} - Unicode Character 'CARRIAGE RETURN (CR)'
• \x{2028} - Unicode Character 'LINE SEPARATOR'
• \x{2028} - Unicode Character 'PARAGRAPH SEPARATOR'.

Also see: Unicode character table.

[three18ti]

This is great. Thank you!

So like most things in computing, the zeros are omitted, so \x{A} is actually \x{000A}.

[Kenosis]

You're most welcome, three18ti!

Perl expectedly parses both as "\n" (the leading zeros aren't significant):

perl -MO=Deparse,-p -e 'print "\x{A}"'

Output:

print("\n");
-e syntax OK

And:

use warnings;
use strict;

print ord "\x{A}" if "\x{000A}" eq "\n";

Output:

10

As you see, \x{A}, \x{000A} and \n all represent the same character.