Introspection with MOP
MOP stands for Meta-object protocol. In Raku, it allows to get additional information about the objects in the program, such as containers or variables.
Condider a type-constrained variable:
my Int $int;
Debugging this variable using .^name reveals its type.
my Int $int;
say $int.^name; # Int
In this program, ^name is a built-in method that returns the type of the value kept in the container. This is a part of the so-called metaobject that contains meta-information about the container.
Here is a modified example from the earlier topic:
my $value;
say $value.^name;
$value = 42;
say $value.^name;
$value = 'fourty-two';
say $value.^name;
This time, the program only prints type names:
Any
Int
Str