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What is the difference between Perl 6 DEFINITE and specific methods?

Type objects are always undefined, but I saw some tests that use .defined and some that use .DEFINITE . Are there any cases when they can be different? I tend to think that any method in which all uppercase letters are not intended for everyday work prefers .defined for this task.

 my $class = IntStr; put '-' x 20; # False put $class.DEFINITE; put $class.defined; put '-' x 20; # False $class = Nil; put $class.DEFINITE; put $class.defined; put '-' x 20; # True $class = ''; put $class.DEFINITE; put $class.defined;

As a result, I look for any case where the answers to the two methods are different:

 -------------------- False False -------------------- False False -------------------- True True
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.DEFINITE should be considered a macro (just like .WHAT , .HOW , etc.). It is directly processed in Actions and converted to nqp::p6definite() op.

.defined is a method that lives in Mu and that can be overridden by your class. It is actually overridden for Failure , so the Failure instance can act as an undefined value, for example. a if (and "handle" failure).

 my $a = Failure.new("foo"); say "bar" if $a; # no output say $a; # outputs "(HANDLED) foo", but no longer throws

So, to answer your question:

 my $a = Failure.new("foo"); say $a.DEFINITE; # True say $a.defined; # False
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