Documentation for routine of assembled from the following types:

class Code

From Code

(Code) method of

Defined as:

method of(Code:D: --> Mu)

Returns the return type constraint of the Code:

say -> () --> Int {}.of; # OUTPUT: «(Int)␤»

class Variable

From Variable

(Variable) trait of

multi sub trait_mod:<of>(Mu:U $target, Mu:U $type)

Sets the type constraint of a container bound to a variable.

my $i of Int = 42;
$i = "forty plus two";
CATCH { default { say .^name, ' ', .Str } }
# OUTPUT: «X::TypeCheck::Assignment Type check failed in assignment to $i; expected Int but got Str ("forty plus two")␤»

You can use any value defined in compile time as a type constraint, including constants:

constant \T = Int;
my $i of T = 42;

which would be equivalent to the previous definition.

role Positional

From Positional

(Positional) method of

method of()

Returns the type constraint for elements of the positional container. Defaults to Mu.

class Scalar

From Scalar

(Scalar) method of

method of(Scalar:D: --> Mu)

Returns the type constraint of the container.

Example:

my Cool $x = 42;
say $x.VAR.of;                  # OUTPUT: «(Cool)»

class Array

From Array

(Array) method of

Defined as:

method of

Returns the type constraint for the values of the invocant. By default, i.e. if no type constraint is given during declaration, the method returns (Mu).

my @a1 = 1, 'two', 3.14159;              # (no type constraint specified) 
say @a1.of;                              # OUTPUT: «(Mu)␤» 
 
my Int @a2 = 1, 2, 3;                    # (values must be of type Int) 
say @a2.of;                              # OUTPUT: «(Int)␤» 
@a2.push: 'd';
CATCH { default { put .^name, ': ', .Str } };
# OUTPUT: «X::TypeCheck::Assignment: Type check failed in assignment to @a2; expected Int but got Str ("d")␤»

class Hash

From Hash

(Hash) method of

Defined as:

method of()

Returns the type constraint for the values of the invocant. By default, i.e., if no type constraint is given during declaration, the method returns (Mu).

my %h1 = 'apples' => 3, 'oranges' => 7;  # (no type constraint specified) 
say %h1.of;                              # OUTPUT: «(Mu)␤» 
 
my Int %h2 = 'oranges' => 7;             # (values must be of type Int) 
say %h2.of;                              # OUTPUT: «(Int)␤»

role QuantHash

From QuantHash

(QuantHash) method of

method of()

Returns the type of value a value of this QuantHash may have. This is typically Bool for Setty, UInt for Baggy or Real for Mixy roles.

role Associative

From Associative

(Associative) method of

Defined as:

method of()

Associative is actually a parameterized role which can use different classes for keys and values. As seen at the top of the document, by default it coerces to Str for the key and uses a very generic Mu for value.

my %any-hash;
say %any-hash.of;#  OUTPUT: «(Mu)␤»

The value is the first parameter you use when instantiating Associative with particular classes:

class DateHash is Hash does Associative[Cool,DateTime] {};
my %date-hash := DateHash.new;
say %date-hash.of; # OUTPUT: «(Cool)␤»