class Reference


Reference is the base class of classes you define in your program. It is set as a class' superclass when you don't specify one:

class MyClass # < Reference

A reference type is passed by reference: when you pass it to methods, return it from methods or assign it to variables, a pointer is actually passed.

Invoking new on a Reference allocates a new instance on the heap. The instance's memory is automatically freed (garbage-collected) when the instance is no longer referred by any other entity in the program.

Direct Known Subclasses

Defined in:


Instance Method Summary

Instance methods inherited from class Object

!=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
, =~(other) =~, class class, dup dup, hash hash, inspect(io : IO)
, itself itself, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, tap(&block) tap, to_json(io : IO)
, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ")
, to_s
to_s(io : IO)
, to_yaml(io : IO)
, try(&block) try, unsafe_as(type : T.class) forall T unsafe_as

Constructor methods inherited from class Object

from_json(string_or_io, root : String) : self
from_json(string_or_io) : self
, from_yaml(string_or_io) : self from_yaml

Constructor Detail

def #

[View source]

Instance Method Detail

def ==(other : self) #

Returns true if this reference is the same as other. Invokes #same?.

[View source]
def ==(other) #

Returns false (other can only be a Value here).

[View source]
def dup #

Returns a shallow copy of this object.

This allocates a new object and copies the contents of self into it.

[View source]
def hash #

Returns this reference's #object_id as the hash value.

[View source]
def inspect(io : IO) : Nil #

[View source]
def object_id : UInt64 #

Returns a UInt64 that uniquely identifies this object.

The returned value is the memory address of this object.

string = "hello"
string.object_id # => 4460249568

pointer = Pointer(String).new(string.object_id)
string2 =
string2.object_id == string.object_id # => true

[View source]
def pretty_print(pp) : Nil #

[View source]
def same?(other : Reference) #

Returns true if this reference is the same as other. This is only true if this reference's #object_id is the same as other's.

[View source]
def same?(other : Nil) #

Returns false: a reference is never nil.

[View source]
def to_s(io : IO) : Nil #

[View source]