abstract class Class

Defined in:

class.cr
primitives.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from struct Value

==(other : Log::Metadata::Value)
==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup

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 : String | IO, root : String)
from_json(string_or_io : String | 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

def self.cast(other) : self #

Castsother to this class.

This is the same as usingas, but allows the class to be passed around as an argument. See the documentation on as for more information.

klass = Int32
number = [99, "str"][0]
typeof(number)             # => (String | Int32)
typeof(klass.cast(number)) # => Int32

Class Method Detail

def self.<(other : T.class) : Bool forall T #

Returnswhether this class inherits or includesother.

Int32 < Number  # => true
Int32 < Value   # => true
Int32 < Int32   # => false
Int32 <= String # => false

def self.<=(other : T.class) : Bool forall T #

Returnswhether this class inherits or includesother, or is equal toother.

Int32 < Number  # => true
Int32 < Value   # => true
Int32 <= Int32  # => true
Int32 <= String # => false

def self.==(other : Class) : Bool #

Returnswhether this class is the same asother.

Int32 == Int32  # => true
Int32 == String # => false

def self.===(other) #
Description copied from class Object

Case equality.

The#=== method is used in acase ... when ... end expression.

For example, this code:

case value
when x
  # something when x
when y
  # something when y
end

Is equivalent to this code:

if x === value
  # something when x
elsif y === value
  # something when y
end

Object simply implements#=== by invoking#==, but subclasses (notablyRegex) can override it to provide meaningful case-equality semantics.


def self.>(other : T.class) : Bool forall T #

Returnswhetherother inherits or includesself.

Number > Int32  # => true
Number > Number # => false
Number > Object # => false

def self.>=(other : T.class) forall T #

Returnswhetherother inherits or includesself, or is equal toself.

Number >= Int32  # => true
Number >= Number # => true
Number >= Object # => false

def self.|(other : U.class) forall U #

Returns the union type ofself andother.

Int32 | Char # => (Int32 | Char)

def self.clone #

def self.dup #
Description copied from struct Value

Returns a shallow copy of this object.

BecauseValue is a value type, this method returnsself, which already involves a shallow copy of this object because value types are passed by value.


def self.hash(hasher) #

SeeObject#hash(hasher)


def self.inspect(io : IO) : Nil #
Description copied from class Object

Prints toio an unambiguous and information-rich string representation of this object, typically intended for developers.

It is similar to#to_s(IO), but often provides more information. Ideally, it should contain sufficient information to be able to recreate an objectwith the same value (given an identical environment).

For types that don't provide a custom implementation of this method, default implementation delegates to#to_s(IO). This said, it is advisable to have an appropriate#inspect implementation on every type. Default implementations are provided byStruct#inspect andReference#inspect.

::p and::p! use this method to print an object inSTDOUT.


def self.name : String #

Returns the name of this class.

String.name # => "String"

def self.nilable? : Bool #

Returnstrue ifnil is an instance of this type.

Int32.nilable?            # => false
Nil.nilable?              # => true
(Int32 | String).nilable? # => false
(Int32 | Nil).nilable?    # => true
NoReturn.nilable?         # => false
Value.nilable?            # => true

def self.to_s(io : IO) : Nil #
Description copied from class Object

Prints a nicely readable and concise string representation of this object, typically intended for users, toio.

This method is calledwhen an object is interpolated in a string literal:

"foo #{bar} baz" # calls bar.to_io with the builder for this string

IO#<< calls this method to append an object to itself:

io << bar # calls bar.to_s(io)

Thus implementations must not interpolateself in a string literal or call io << selfwhich bothwould lead to an endless loop.

Also see#inspect(IO).


Instance Method Detail

def <(other : T.class) : Bool forall T #

Returnswhether this class inherits or includesother.

Int32 < Number  # => true
Int32 < Value   # => true
Int32 < Int32   # => false
Int32 <= String # => false

def <=(other : T.class) : Bool forall T #

Returnswhether this class inherits or includesother, or is equal toother.

Int32 < Number  # => true
Int32 < Value   # => true
Int32 <= Int32  # => true
Int32 <= String # => false

def ==(other : Class) : Bool #

Returnswhether this class is the same asother.

Int32 == Int32  # => true
Int32 == String # => false

def ===(other) #
Description copied from class Object

Case equality.

The#=== method is used in acase ... when ... end expression.

For example, this code:

case value
when x
  # something when x
when y
  # something when y
end

Is equivalent to this code:

if x === value
  # something when x
elsif y === value
  # something when y
end

Object simply implements#=== by invoking#==, but subclasses (notablyRegex) can override it to provide meaningful case-equality semantics.


def >(other : T.class) : Bool forall T #

Returnswhetherother inherits or includesself.

Number > Int32  # => true
Number > Number # => false
Number > Object # => false

def >=(other : T.class) forall T #

Returnswhetherother inherits or includesself, or is equal toself.

Number >= Int32  # => true
Number >= Number # => true
Number >= Object # => false

def |(other : U.class) forall U #

Returns the union type ofself andother.

Int32 | Char # => (Int32 | Char)

def cast(other) : self #

Castsother to this class.

This is the same as usingas, but allows the class to be passed around as an argument. See the documentation on as for more information.

klass = Int32
number = [99, "str"][0]
typeof(number)             # => (String | Int32)
typeof(klass.cast(number)) # => Int32

def clone #

def dup #
Description copied from struct Value

Returns a shallow copy of this object.

BecauseValue is a value type, this method returnsself, which already involves a shallow copy of this object because value types are passed by value.


def hash(hasher) #

SeeObject#hash(hasher)


def inspect(io : IO) : Nil #
Description copied from class Object

Prints toio an unambiguous and information-rich string representation of this object, typically intended for developers.

It is similar to#to_s(IO), but often provides more information. Ideally, it should contain sufficient information to be able to recreate an objectwith the same value (given an identical environment).

For types that don't provide a custom implementation of this method, default implementation delegates to#to_s(IO). This said, it is advisable to have an appropriate#inspect implementation on every type. Default implementations are provided byStruct#inspect andReference#inspect.

::p and::p! use this method to print an object inSTDOUT.


def name : String #

Returns the name of this class.

String.name # => "String"

def nilable? : Bool #

Returnstrue ifnil is an instance of this type.

Int32.nilable?            # => false
Nil.nilable?              # => true
(Int32 | String).nilable? # => false
(Int32 | Nil).nilable?    # => true
NoReturn.nilable?         # => false
Value.nilable?            # => true

def to_s(io : IO) : Nil #
Description copied from class Object

Prints a nicely readable and concise string representation of this object, typically intended for users, toio.

This method is calledwhen an object is interpolated in a string literal:

"foo #{bar} baz" # calls bar.to_io with the builder for this string

IO#<< calls this method to append an object to itself:

io << bar # calls bar.to_s(io)

Thus implementations must not interpolateself in a string literal or call io << selfwhich bothwould lead to an endless loop.

Also see#inspect(IO).