class Box(T)

Overview

A Box allows turning any object to a Void* and back.

A Box's purpose is passing data to C as a Void* and then converting that back to the original data type.

For an example usage, see Proc's explanation about sending Procs to C.

Defined in:

box.cr

Constructors

Class Method Summary

Instance Method Summary

Instance methods inherited from class Reference

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
==(other)
==
, dup dup, hash(hasher) hash, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference)
same?(other : Nil)
same?
, to_s(io : IO) : Nil to_s

Constructor methods inherited from class Reference

new new

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
hash(hasher)
hash
, inspect(io : IO) : Nil
inspect : String
inspect
, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, 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)
to_json
to_json
, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ")
to_pretty_json
, to_s : String
to_s(io : IO) : Nil
to_s
, to_yaml(io : IO)
to_yaml
to_yaml
, try(&) 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_json
, from_yaml(string_or_io : String | IO) : self from_yaml

Constructor Detail

def self.new(object : T) #

Creates a Box with the given object.

This method isn't usually used directly. Instead, Box.box is used.


[View source]

Class Method Detail

def self.box(r : Reference?) : Pointer(Void) #

Creates a Box for a reference type (or nil) and returns the same pointer (or NULL)


[View source]
def self.box(object) : Pointer(Void) #

Creates a Box for an object and returns it as a Void*.


[View source]
def self.unbox(pointer : Pointer(Void)) : T #

Unboxes a Void* into an object of type T. Note that for this you must specify T: Box(T).unbox(data).


[View source]

Instance Method Detail

def object : T #

Returns the original object


[View source]