Returns true
if obj is an instance of the given class. See also Object#kind_of?
.
class A; end class B < A; end class C < B; end b = B.new b.instance_of? A #=> false b.instance_of? B #=> true b.instance_of? C #=> false
Similar to method, searches singleton method only.
class Demo def initialize(n) @iv = n end def hello() "Hello, @iv = #{@iv}" end end k = Demo.new(99) def k.hi "Hi, @iv = #{@iv}" end m = k.singleton_method(:hi) m.call #=> "Hi, @iv = 99" m = k.singleton_method(:hello) #=> NameError
Creates an accessor method to allow assignment to the attribute symbol.id2name
. String
arguments are converted to symbols.
Returns an array containing the names of the public and protected instance methods in the receiver. For a module, these are the public and protected methods; for a class, they are the instance (not singleton) methods. If the optional parameter is false
, the methods of any ancestors are not included.
module A def method1() end end class B include A def method2() end end class C < B def method3() end end A.instance_methods(false) #=> [:method1] B.instance_methods(false) #=> [:method2] B.instance_methods(true).include?(:method1) #=> true C.instance_methods(false) #=> [:method3] C.instance_methods.include?(:method2) #=> true
Says whether mod or its ancestors have a constant with the given name:
Float.const_defined?(:EPSILON) #=> true, found in Float itself Float.const_defined?("String") #=> true, found in Object (ancestor) BasicObject.const_defined?(:Hash) #=> false
If mod is a Module
, additionally Object
and its ancestors are checked:
Math.const_defined?(:String) #=> true, found in Object
In each of the checked classes or modules, if the constant is not present but there is an autoload for it, true
is returned directly without autoloading:
module Admin autoload :User, 'admin/user' end Admin.const_defined?(:User) #=> true
If the constant is not found the callback const_missing
is not called and the method returns false
.
If inherit
is false, the lookup only checks the constants in the receiver:
IO.const_defined?(:SYNC) #=> true, found in File::Constants (ancestor) IO.const_defined?(:SYNC, false) #=> false, not found in IO itself
In this case, the same logic for autoloading applies.
If the argument is not a valid constant name a NameError
is raised with the message “wrong constant name name”:
Hash.const_defined? 'foobar' #=> NameError: wrong constant name foobar
Makes a list of existing constants private.
Returns true
if mod is a singleton class or false
if it is an ordinary class or module.
class C end C.singleton_class? #=> false C.singleton_class.singleton_class? #=> true
Returns an UnboundMethod
representing the given instance method in mod.
class Interpreter def do_a() print "there, "; end def do_d() print "Hello "; end def do_e() print "!\n"; end def do_v() print "Dave"; end Dispatcher = { "a" => instance_method(:do_a), "d" => instance_method(:do_d), "e" => instance_method(:do_e), "v" => instance_method(:do_v) } def interpret(string) string.each_char {|b| Dispatcher[b].bind(self).call } end end interpreter = Interpreter.new interpreter.interpret('dave')
produces:
Hello there, Dave!
IO.copy_stream
copies src to dst. src and dst is either a filename or an IO-like object. IO-like object for src should have readpartial
or read
method. IO-like object for dst should have write
method. (Specialized mechanisms, such as sendfile system call, may be used on appropriate situation.)
This method returns the number of bytes copied.
If optional arguments are not given, the start position of the copy is the beginning of the filename or the current file offset of the IO
. The end position of the copy is the end of file.
If copy_length is given, No more than copy_length bytes are copied.
If src_offset is given, it specifies the start position of the copy.
When src_offset is specified and src is an IO
, IO.copy_stream
doesn’t move the current file offset.
Returns the Encoding
object that represents the encoding of the file. If io is in write mode and no encoding is specified, returns nil
.
If single argument is specified, read string from io is tagged with the encoding specified. If encoding is a colon separated two encoding names “A:B”, the read string is converted from encoding A (external encoding) to encoding B (internal encoding), then tagged with B. If two arguments are specified, those must be encoding objects or encoding names, and the first one is the external encoding, and the second one is the internal encoding. If the external encoding and the internal encoding is specified, optional hash argument specify the conversion option.
Returns false if rxp is applicable to a string with any ASCII compatible encoding. Returns true otherwise.
r = /a/ r.fixed_encoding? #=> false r =~ "\u{6666} a" #=> 2 r =~ "\xa1\xa2 a".force_encoding("euc-jp") #=> 2 r =~ "abc".force_encoding("euc-jp") #=> 0 r = /a/u r.fixed_encoding? #=> true r.encoding #=> #<Encoding:UTF-8> r =~ "\u{6666} a" #=> 2 r =~ "\xa1\xa2".force_encoding("euc-jp") #=> Encoding::CompatibilityError r =~ "abc".force_encoding("euc-jp") #=> 0 r = /\u{6666}/ r.fixed_encoding? #=> true r.encoding #=> #<Encoding:UTF-8> r =~ "\u{6666} a" #=> 0 r =~ "\xa1\xa2".force_encoding("euc-jp") #=> Encoding::CompatibilityError r =~ "abc".force_encoding("euc-jp") #=> nil
creates an Addrinfo
object from the arguments.
The arguments are interpreted as similar to self.
Addrinfo.tcp("0.0.0.0", 4649).family_addrinfo("www.ruby-lang.org", 80) #=> #<Addrinfo: 221.186.184.68:80 TCP (www.ruby-lang.org:80)> Addrinfo.unix("/tmp/sock").family_addrinfo("/tmp/sock2") #=> #<Addrinfo: /tmp/sock2 SOCK_STREAM>
Returns the Encoding
object that represents the encoding of the file. If strio is write mode and no encoding is specified, returns nil
.
Specify the encoding of the StringIO
as ext_enc. Use the default external encoding if ext_enc is nil. 2nd argument int_enc and optional hash opt argument are ignored; they are for API compatibility to IO
.
Calls WIN32OLE#invoke
method.
Returns the method kind string. The string is “UNKNOWN” or “PROPERTY” or “PROPERTY” or “PROPERTYGET” or “PROPERTYPUT” or “PROPERTYPPUTREF” or “FUNC”.
tobj = WIN32OLE_TYPE.new('Microsoft Excel 9.0 Object Library', 'Workbooks') method = WIN32OLE_METHOD.new(tobj, 'Add') puts method.invoke_kind # => "FUNC"
Returns value specified by the member name of VT_RECORD OLE variable. Or sets value specified by the member name of VT_RECORD OLE variable. If the member name is not correct, KeyError
exception is raised.
If COM server in VB.NET ComServer project is the following:
Imports System.Runtime.InteropServices Public Class ComClass Public Structure Book <MarshalAs(UnmanagedType.BStr)> _ Public title As String Public cost As Integer End Structure End Class
Then getting/setting value from Ruby is as the following:
obj = WIN32OLE.new('ComServer.ComClass') book = WIN32OLE_RECORD.new('Book', obj) book.title # => nil ( book.method_missing(:title) is invoked. ) book.title = "Ruby" # ( book.method_missing(:title=, "Ruby") is invoked. )
Returns variable kind string.
tobj = WIN32OLE_TYPE.new('Microsoft Excel 9.0 Object Library', 'XlSheetType') variables = tobj.variables variables.each do |variable| puts "#{variable.name} #{variable.variable_kind}" end The result of above script is following: xlChart CONSTANT xlDialogSheet CONSTANT xlExcel4IntlMacroSheet CONSTANT xlExcel4MacroSheet CONSTANT xlWorksheet CONSTANT
Evaluates a string containing Ruby source code, or the given block, within the context of the receiver (obj). In order to set the context, the variable self
is set to obj while the code is executing, giving the code access to obj’s instance variables and private methods.
When instance_eval
is given a block, obj is also passed in as the block’s only argument.
When instance_eval
is given a String
, the optional second and third parameters supply a filename and starting line number that are used when reporting compilation errors.
class KlassWithSecret def initialize @secret = 99 end private def the_secret "Ssssh! The secret is #{@secret}." end end k = KlassWithSecret.new k.instance_eval { @secret } #=> 99 k.instance_eval { the_secret } #=> "Ssssh! The secret is 99." k.instance_eval {|obj| obj == self } #=> true
Executes the given block within the context of the receiver (obj). In order to set the context, the variable self
is set to obj while the code is executing, giving the code access to obj’s instance variables. Arguments are passed as block parameters.
class KlassWithSecret def initialize @secret = 99 end end k = KlassWithSecret.new k.instance_exec(5) {|x| @secret+x } #=> 104
Invoked by Ruby when obj is sent a message it cannot handle. symbol is the symbol for the method called, and args are any arguments that were passed to it. By default, the interpreter raises an error when this method is called. However, it is possible to override the method to provide more dynamic behavior. If it is decided that a particular method should not be handled, then super should be called, so that ancestors can pick up the missing method. The example below creates a class Roman
, which responds to methods with names consisting of roman numerals, returning the corresponding integer values.
class Roman def roman_to_int(str) # ... end def method_missing(methId) str = methId.id2name roman_to_int(str) end end r = Roman.new r.iv #=> 4 r.xxiii #=> 23 r.mm #=> 2000
Returns the external encoding for files read from ARGF
as an Encoding
object. The external encoding is the encoding of the text as stored in a file. Contrast with ARGF.internal_encoding
, which is the encoding used to represent this text within Ruby.
To set the external encoding use ARGF.set_encoding
.
For example:
ARGF.external_encoding #=> #<Encoding:UTF-8>
If single argument is specified, strings read from ARGF
are tagged with the encoding specified.
If two encoding names separated by a colon are given, e.g. “ascii:utf-8”, the read string is converted from the first encoding (external encoding) to the second encoding (internal encoding), then tagged with the second encoding.
If two arguments are specified, they must be encoding objects or encoding names. Again, the first specifies the external encoding; the second specifies the internal encoding.
If the external encoding and the internal encoding are specified, the optional Hash
argument can be used to adjust the conversion process. The structure of this hash is explained in the String#encode
documentation.
For example:
ARGF.set_encoding('ascii') # Tag the input as US-ASCII text ARGF.set_encoding(Encoding::UTF_8) # Tag the input as UTF-8 text ARGF.set_encoding('utf-8','ascii') # Transcode the input from US-ASCII # to UTF-8.