DO NOT WRITE ANY MAGIC COMMENT HERE.
Returns the value of the given instance variable, or nil if the instance variable is not set. The @
part of the variable name should be included for regular instance variables. Throws a NameError
exception if the supplied symbol is not valid as an instance variable name. String arguments are converted to symbols.
class Fred def initialize(p1, p2) @a, @b = p1, p2 end end fred = Fred.new('cat', 99) fred.instance_variable_get(:@a) #=> "cat" fred.instance_variable_get("@b") #=> 99
Sets the instance variable named by symbol to the given object, thereby frustrating the efforts of the class’s author to attempt to provide proper encapsulation. The variable does not have to exist prior to this call. If the instance variable name is passed as a string, that string is converted to a symbol.
class Fred def initialize(p1, p2) @a, @b = p1, p2 end end fred = Fred.new('cat', 99) fred.instance_variable_set(:@a, 'dog') #=> "dog" fred.instance_variable_set(:@c, 'cat') #=> "cat" fred.inspect #=> "#<Fred:0x401b3da8 @a=\"dog\", @b=99, @c=\"cat\">"
Removes the named instance variable from obj, returning that variable’s value.
class Dummy attr_reader :var def initialize @var = 99 end def remove remove_instance_variable(:@var) end end d = Dummy.new d.var #=> 99 d.remove #=> 99 d.var #=> nil
Returns a list of the public instance methods defined in mod. If the optional parameter is false
, the methods of any ancestors are not included.
Returns a list of the protected instance methods defined in mod. If the optional parameter is false
, the methods of any ancestors are not included.
Returns a list of the private instance methods defined in mod. If the optional parameter is false
, the methods of any ancestors are not included.
module Mod def method1() end private :method1 def method2() end end Mod.instance_methods #=> [:method2] Mod.private_instance_methods #=> [:method1]
Returns true
if the given class variable is defined in obj. String arguments are converted to symbols.
class Fred @@foo = 99 end Fred.class_variable_defined?(:@@foo) #=> true Fred.class_variable_defined?(:@@bar) #=> false
Similar to instance_method, searches public method only.
Returns true
if the named public method is defined by mod (or its included modules and, if mod is a class, its ancestors). String arguments are converted to symbols.
module A def method1() end end class B protected def method2() end end class C < B include A def method3() end end A.method_defined? :method1 #=> true C.public_method_defined? "method1" #=> true C.public_method_defined? "method2" #=> false C.method_defined? "method2" #=> true
Returns true
if the named private method is defined by _ mod_ (or its included modules and, if mod is a class, its ancestors). String arguments are converted to symbols.
module A def method1() end end class B private def method2() end end class C < B include A def method3() end end A.method_defined? :method1 #=> true C.private_method_defined? "method1" #=> false C.private_method_defined? "method2" #=> true C.method_defined? "method2" #=> false
Returns true
if the named protected method is defined by mod (or its included modules and, if mod is a class, its ancestors). String arguments are converted to symbols.
module A def method1() end end class B protected def method2() end end class C < B include A def method3() end end A.method_defined? :method1 #=> true C.protected_method_defined? "method1" #=> false C.protected_method_defined? "method2" #=> true C.method_defined? "method2" #=> true
Execute the provided block, but preserve the rounding mode
BigDecimal.save_rounding_mode do BigDecimal.mode(BigDecimal::ROUND_MODE, :up) puts BigDecimal.mode(BigDecimal::ROUND_MODE) end
For use with the BigDecimal::ROUND_*
See BigDecimal.mode
Packs port and host as an AF_INET/AF_INET6 sockaddr string.
Socket.sockaddr_in(80, "127.0.0.1") #=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00" Socket.sockaddr_in(80, "::1") #=> "\n\x00\x00P\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00\x00"
Unpacks sockaddr into port and ip_address.
sockaddr should be a string or an addrinfo for AF_INET/AF_INET6.
sockaddr = Socket.sockaddr_in(80, "127.0.0.1") p sockaddr #=> "\x02\x00\x00P\x7F\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00" p Socket.unpack_sockaddr_in(sockaddr) #=> [80, "127.0.0.1"]
Returns true for IPv6 multicast link-local scope address. It returns false otherwise.
Initialize WIN32OLE
object(ActiveX Control) by calling IPersistMemory::InitNew.
Before calling OLE method, some kind of the ActiveX controls created with MFC should be initialized by calling IPersistXXX::InitNew.
If and only if you received the exception “HRESULT error code: 0x8000ffff catastrophic failure”, try this method before invoking any ole_method.
obj = WIN32OLE.new("ProgID_or_GUID_of_ActiveX_Control") obj.ole_activex_initialize obj.method(...)
Returns WIN32OLE
object for a specific dispatch or dual interface specified by iid.
ie = WIN32OLE.new('InternetExplorer.Application') ie_web_app = ie.ole_query_interface('{0002DF05-0000-0000-C000-000000000046}') # => WIN32OLE object for dispinterface IWebBrowserApp
Invoked as a callback whenever a singleton method is added to the receiver.
module Chatty def Chatty.singleton_method_added(id) puts "Adding #{id.id2name}" end def self.one() end def two() end def Chatty.three() end end
produces:
Adding singleton_method_added Adding one Adding three
Invoked as a callback whenever a singleton method is removed from the receiver.
module Chatty def Chatty.singleton_method_removed(id) puts "Removing #{id.id2name}" end def self.one() end def two() end def Chatty.three() end class << self remove_method :three remove_method :one end end
produces:
Removing three Removing one
Same as each
, but the row index and column index in addition to the element
Matrix[ [1,2], [3,4] ].each_with_index do |e, row, col| puts "#{e} at #{row}, #{col}" end # => Prints: # 1 at 0, 0 # 2 at 0, 1 # 3 at 1, 0 # 4 at 1, 1
Raises PStore::Error
if the calling code is not in a PStore#transaction
or if the code is in a read-only PStore#transaction
.