Course of Raku / Advanced / Containers / Introspecting containers

Using VAR

VAR is a pseudo-method that returns the underlying container object. For a scalar variable, the .VAR call returns the Scalar container behind it.

^name

Once you have the container, you can ask for the name of its class with .^name:

my $var1 = 42;
my $var2 = '42';

say $var1.^name;     # Int
say $var1.VAR.^name; # Scalar

say $var2.^name;     # Str
say $var2.VAR.^name; # Scalar

.^name on the variable returns the type of the value (Int or Str), while .VAR.^name returns the type of the container, which is Scalar in both cases.

default

The default method returns the default value of the container — what you get when the container holds nothing of its own. With the is default trait you set it explicitly:

my Str $language is default('Raku');
say $language.VAR.default; # Raku

Without an explicit default, the default value is the container’s type. For an untyped container that is Any, regardless of what value it currently holds:

my $language = 'Raku';
say $language.VAR.default; # (Any)

For a typed container it is the constraint type:

my Str $language;
say $language.VAR.default; # (Str)

name

The name method returns the name of the container, including the sigil:

my $language;
say $language.VAR.name; # $language

Take care not to mix up ^name (the type) and name (the variable’s own name).

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