Newline handling in Perl 6

How the different newline characters are handled, and how to change the behavior

Different operating systems use different characters, or combinations of them, to represent the transition to a new line. Every language has its own set of rules to handle this. Perl 6 has the following ones:

You can change the default behavior for a particular handle by setting the :nl-out attribute when you create that handle.

my $crlf-out = open('<STDOUT>'), :nl-out("\\\n\r"));
$*OUT.say: 1;     #OUTPUT: «1␤» 
$crlf-out.say: 1#OUTPUT: «1\␤␍» 

In this example, where we are replicating standard output to a new handle by using IO::Special, we are appending a \ to the end of the string, followed by a newline and a carriage return ; everything we print to that handle will get those characters at the end of the line, as shown.

In regular expressions, \n is defined in terms of the Unicode definition of logical newline. It will match . and also \v, as well as any class that includes whitespace.