role QuantHash does Associative { }

The QuantHash role provides the basic functionality shared by the Setty, Baggy and Mixy roles. These provide object hashes whose values are limited in some way.

QuantHashes are what set operators use internally.

Methods

method hash

method hash()

Coerces the QuantHash object to a Hash (by stringifying the objects for the keys) with the values of the hash limited to the same limitation as QuantHash, and returns that.

method Hash

method Hash()

Coerces the QuantHash object to a Hash (by stringifying the objects for the keys) without any limitations on the values, and returns that.

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.

method keyof

method keyof()

Returns the type of value a key of this subclass of QuantHash may have. This is typically Mu, which is also the default for punned QuantHashes.

method Capture

Defined as

method Capture()

Returns the object as a Capture by previously coercing it to a Hash.

method list

Defined as:

multi method list(QuantHash:D:)

Returns a list of Pair objects of all keys and values in the QuantHash.

method Setty

method Setty(--> Setty:D)

Coerce the QuantHash object to the equivalent object that uses the Setty role. Note that for Mixy type coercion items with negative values will be skipped.

my %b is Bag = one => 1, two => 2;
say %b.Setty; # OUTPUT: «Set(one two)␤» 
my %m is Mix = one => 1, minus => -1;
say %m.Setty; # OUTPUT: «Set(one)␤»

method Baggy

method Baggy(--> Baggy:D)

Coerce the QuantHash object to the equivalent object that uses the Baggy role. Note that for Mixy type coercion items with negative values will be skipped.

my %s is Set = <one two>;
say %s.Baggy; # OUTPUT: «Bag(one two)␤» 
my %m is Mix = one => 1, minus => -1;
say %m.Baggy; # OUTPUT: «Bag(one)␤»

method Mixy

method Mixy(--> Mixy:D)

Coerce the QuantHash object to the equivalent object that uses the Mixy role.

my %s is Set = <one two>;
say %s.Mixy; # OUTPUT: «Mix(one two)␤» 
my %b is Bag = one => 1, two => 2;
say %b.Mixy; # OUTPUT: «Mix(one two(2))␤»

Type Graph

Routines supplied by role Associative

QuantHash does role Associative, which provides the following routines:

(Associative) method of

Defined as:

method of()

Associative, as the definition above shows, 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 the key to Str 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)␤»

(Associative) method keyof

Defined as:

method keyof()

Returns the parameterized key used for the Associative role, which is Any coerced to Str by default. This is the class used as second parameter when you use the parameterized version of Associative.

my %any-hash;
%any-hash.keyof; # OUTPUT: «(Str(Any))␤»

(Associative) method AT-KEY

method AT-KEY(\key)

Should return the value / container at the given key.

class What { method AT-KEY(\key) { 42 }};
say What.new{33}; # OUTPUT: «42␤» 

(Associative) method EXISTS-KEY

method EXISTS-KEY(\key)

Should return a Bool indicating whether the given key actually has a value.

(Associative) method STORE

method STORE(\values, :$INITIALIZE)

This method should only be supplied if you want to support the:

my %h is Foo = a => 42, b => 666;

syntax for binding your implementation of the Associative role.

Should accept the values to (re-)initialize the object with, which either could consist of Pairs, or separate key/value pairs. The optional named parameter will contain a True value when the method is called on the object for the first time. Should return the invocant.