class Reference
Overview
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
end
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
- Array(T)
- Benchmark::BM::Job
- Benchmark::BM::Tms
- Benchmark::IPS::Entry
- Benchmark::IPS::Job
- Box(T)
- Channel(T)
- Compress::Gzip::Header
- Compress::Zip::File
- Compress::Zip::File::Entry
- Compress::Zip::Reader
- Compress::Zip::Reader::Entry
- Compress::Zip::Writer
- Compress::Zip::Writer::Entry
- Crypto::Bcrypt
- Crypto::Bcrypt::Password
- Crypto::Blowfish
- Crystal::EventLoop
- Crystal::EventLoop::Polling::Arena(T, BLOCK_BYTESIZE)
- Crystal::EventLoop::Polling::FiberEvent
- Crystal::Macros::ASTNode
- Crystal::SyntaxHighlighter
- CSV
- CSV::Builder
- CSV::Lexer
- CSV::Parser
- Deque(T)
- Digest
- Dir
- Exception
- Fiber
- Hash(K, V)
- HTTP::Client
- HTTP::Client::Response
- HTTP::CompressHandler
- HTTP::Cookie
- HTTP::Cookies
- HTTP::ErrorHandler
- HTTP::FormData::Builder
- HTTP::FormData::Parser
- HTTP::LogHandler
- HTTP::Request
- HTTP::Server
- HTTP::Server::Context
- HTTP::Server::RequestProcessor
- HTTP::StaticFileHandler
- HTTP::WebSocket
- HTTP::WebSocketHandler
- IO
- Iterator::Stop
- JSON::Builder
- JSON::Lexer
- JSON::Parser
- JSON::PullParser
- JSON::Token
- Levenshtein::Finder
- LLVM::ABI
- LLVM::ABI::FunctionType
- LLVM::Builder
- LLVM::Context
- LLVM::FunctionPassManager
- LLVM::GenericValue
- LLVM::JITCompiler
- LLVM::MemoryBuffer
- LLVM::Module
- LLVM::ModulePassManager
- LLVM::Orc::JITDylib
- LLVM::Orc::LLJIT
- LLVM::Orc::LLJITBuilder
- LLVM::Orc::ThreadSafeContext
- LLVM::Orc::ThreadSafeModule
- LLVM::PassBuilderOptions
- LLVM::PassManagerBuilder
- LLVM::TargetMachine
- Log
- Log::AsyncDispatcher
- Log::Backend
- Log::Builder
- Log::EntriesChecker
- Log::Metadata
- Log::SyncDispatcher
- MIME::Multipart::Builder
- MIME::Multipart::Parser
- Mutex
- OAuth2::AccessToken
- OAuth2::Client
- OAuth2::Session
- OAuth::AccessToken
- OAuth::Consumer
- OAuth::RequestToken
- OpenSSL::Cipher
- OpenSSL::HMAC
- OpenSSL::MD5
- OpenSSL::SHA1
- OpenSSL::SSL::Context
- OpenSSL::SSL::Server
- OptionParser
- PrettyPrint
- Process
- Process::Status
- Random::ISAAC
- Random::PCG32
- Regex
- Spec::Context
- Spec::Example
- Steppable::StepIterator(T, L, B)
- String
- StringPool
- StringScanner
- System::Group
- System::User
- Time::Location
- URI
- URI::Params::Builder
- URI::Punycode
- WaitGroup
- WeakRef(T)
- XML::Attributes
- XML::Builder
- XML::Namespace
- XML::Node
- XML::NodeSet
- XML::Reader
- XML::XPathContext
- YAML::Builder
- YAML::Nodes::Builder
- YAML::Nodes::Node
- YAML::ParseContext
- YAML::PullParser
Defined in:
json/any.crprimitives.cr
reference.cr
yaml/any.cr
Constructors
- .new
-
.unsafe_construct(address : Pointer, *args, **opts) : self
Constructs an object in-place at the given address, forwarding args and opts to
#initialize
.EXPERIMENTAL This API is still under development. Join the discussion about custom reference allocation at #13481.
Class Method Summary
-
.pre_initialize(address : Pointer)
Performs basic initialization so that the given address is ready for use as an object's instance data.
EXPERIMENTAL This API is still under development. Join the discussion about custom reference allocation at #13481.
Instance Method Summary
-
#==(other : self)
Returns
true
if this reference is the same as other. - #==(other : JSON::Any)
- #==(other : YAML::Any)
-
#==(other)
Returns
false
(other can only be aValue
here). -
#dup
Returns a shallow copy of this object.
- #hash(hasher)
- #initialize
-
#inspect(io : IO) : Nil
Appends a String representation of this object which includes its class name, its object address and the values of all instance variables.
-
#object_id : UInt64
Returns a
UInt64
that uniquely identifies this object. - #pretty_print(pp) : Nil
-
#same?(other : Reference) : Bool
Returns
true
if this reference is the same as other. -
#same?(other : Nil)
Returns
false
: a reference is nevernil
. -
#to_s(io : IO) : Nil
Appends a short String representation of this object which includes its class name and its object address.
Instance methods inherited from class Object
! : Bool
!,
!=(other)
!=,
!~(other)
!~,
==(other)
==,
===(other : JSON::Any)===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil!(message)
not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as
Class methods inherited from class Object
from_json(string_or_io, root : String)from_json(string_or_io) from_json, from_yaml(string_or_io : String | IO) from_yaml
Macros inherited from class Object
class_getter(*names, &block)
class_getter,
class_getter!(*names)
class_getter!,
class_getter?(*names, &block)
class_getter?,
class_property(*names, &block)
class_property,
class_property!(*names)
class_property!,
class_property?(*names, &block)
class_property?,
class_setter(*names)
class_setter,
def_clone
def_clone,
def_equals(*fields)
def_equals,
def_equals_and_hash(*fields)
def_equals_and_hash,
def_hash(*fields)
def_hash,
delegate(*methods, to object)
delegate,
forward_missing_to(delegate)
forward_missing_to,
getter(*names, &block)
getter,
getter!(*names)
getter!,
getter?(*names, &block)
getter?,
property(*names, &block)
property,
property!(*names)
property!,
property?(*names, &block)
property?,
setter(*names)
setter
Constructor Detail
Constructs an object in-place at the given address, forwarding args and
opts to #initialize
. Returns that object.
This method can be used to decouple object allocation from initialization.
For example, the instance data might come from a custom allocator, or it
might reside on the stack using a type like ReferenceStorage
.
address must point to a suitably aligned buffer of at least
instance_sizeof(self)
bytes.
WARNING This method is unsafe, as it assumes the caller is responsible for managing the memory at the given address manually.
class Foo
getter i : Int64
getter str = "abc"
def initialize(@i)
end
def finalize
puts "bye"
end
end
foo_buffer = uninitialized ReferenceStorage(Foo)
foo = Foo.unsafe_construct(pointerof(foo_buffer), 123_i64)
begin
foo # => #<Foo:0x... @i=123, @str="abc">
ensure
foo.finalize if foo.responds_to?(:finalize) # prints "bye"
end
See also: Reference.pre_initialize
.
EXPERIMENTAL This API is still under development. Join the discussion about custom reference allocation at #13481.
Class Method Detail
Performs basic initialization so that the given address is ready for use
as an object's instance data. Returns address cast to self
's type.
More specifically, this is the part of object initialization that occurs
after memory allocation and before calling one of the #initialize
overloads. It zeroes the memory, sets up the type ID (necessary for dynamic
dispatch), and then runs all inline instance variable initializers.
address must point to a suitably aligned buffer of at least
instance_sizeof(self)
bytes.
WARNING This method is unsafe, as it assumes the caller is responsible for managing the memory at the given address manually.
class Foo
getter i : Int64
getter str = "abc"
def initialize(@i)
end
def self.alloc_with_libc(i : Int64)
foo_buffer = LibC.malloc(instance_sizeof(Foo))
foo = Foo.pre_initialize(foo_buffer)
foo.i # => 0
foo.str # => "abc"
(foo || "").is_a?(Foo) # => true
foo.initialize(i) # okay
foo
end
end
foo = Foo.alloc_with_libc(123_i64)
foo.i # => 123
See also: Reference.unsafe_construct
.
EXPERIMENTAL This API is still under development. Join the discussion about custom reference allocation at #13481.
Instance Method Detail
Returns a shallow copy of this object.
This allocates a new object and copies the contents of
self
into it.
Appends a String representation of this object which includes its class name, its object address and the values of all instance variables.
class Person
def initialize(@name : String, @age : Int32)
end
end
Person.new("John", 32).inspect # => #<Person:0x10fd31f20 @name="John", @age=32>
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 = pointer.as(String)
string2.object_id == string.object_id # => true
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.
Appends a short String representation of this object which includes its class name and its object address.
class Person
def initialize(@name : String, @age : Int32)
end
end
Person.new("John", 32).to_s # => #<Person:0x10a199f20>