Results for: "remove_const"

Module#remove_const

Removes the definition of the given constant, returning that constant’s previous value. If that constant referred to a module, this will not change that module’s name and can lead to confusion.

Module#remove_method

Removes the method identified by symbol from the current class. For an example, see Module#undef_method. String arguments are converted to symbols.

FileUtils#remove_entry

Removes the entry given by path, which should be the entry for a regular file, a symbolic link, or a directory.

Argument path should be interpretable as a path.

Optional argument force specifies whether to ignore raised exceptions of StandardError and its descendants.

FileUtils::remove_entry

Removes the entry given by path, which should be the entry for a regular file, a symbolic link, or a directory.

Argument path should be interpretable as a path.

Optional argument force specifies whether to ignore raised exceptions of StandardError and its descendants.

FileUtils#remove_file

Removes the file entry given by path, which should be the entry for a regular file or a symbolic link.

Argument path should be interpretable as a path.

Optional argument force specifies whether to ignore raised exceptions of StandardError and its descendants.

Related: methods for deleting.

FileUtils::remove_file

Removes the file entry given by path, which should be the entry for a regular file or a symbolic link.

Argument path should be interpretable as a path.

Optional argument force specifies whether to ignore raised exceptions of StandardError and its descendants.

Related: methods for deleting.

FileUtils#remove_dir

Recursively removes the directory entry given by path, which should be the entry for a regular file, a symbolic link, or a directory.

Argument path should be interpretable as a path.

Optional argument force specifies whether to ignore raised exceptions of StandardError and its descendants.

Related: methods for deleting.

FileUtils::remove_dir

Recursively removes the directory entry given by path, which should be the entry for a regular file, a symbolic link, or a directory.

Argument path should be interpretable as a path.

Optional argument force specifies whether to ignore raised exceptions of StandardError and its descendants.

Related: methods for deleting.

Gem::Uninstaller#remove

spec: the spec of the gem to be uninstalled

Module#const_added

Invoked as a callback whenever a constant is assigned on the receiver

module Chatty
  def self.const_added(const_name)
    super
    puts "Added #{const_name.inspect}"
  end
  FOO = 1
end

produces:

Added :FOO

Module#const_get

Checks for a constant with the given name in mod. If inherit is set, the lookup will also search the ancestors (and Object if mod is a Module).

The value of the constant is returned if a definition is found, otherwise a NameError is raised.

Math.const_get(:PI)   #=> 3.14159265358979

This method will recursively look up constant names if a namespaced class name is provided. For example:

module Foo; class Bar; end end
Object.const_get 'Foo::Bar'

The inherit flag is respected on each lookup. For example:

module Foo
  class Bar
    VAL = 10
  end

  class Baz < Bar; end
end

Object.const_get 'Foo::Baz::VAL'         # => 10
Object.const_get 'Foo::Baz::VAL', false  # => NameError

If the argument is not a valid constant name a NameError will be raised with a warning “wrong constant name”.

Object.const_get 'foobar' #=> NameError: wrong constant name foobar

Module#const_set

Sets the named constant to the given object, returning that object. Creates a new constant if no constant with the given name previously existed.

Math.const_set("HIGH_SCHOOL_PI", 22.0/7.0)   #=> 3.14285714285714
Math::HIGH_SCHOOL_PI - Math::PI              #=> 0.00126448926734968

If sym or str is not a valid constant name a NameError will be raised with a warning “wrong constant name”.

Object.const_set('foobar', 42) #=> NameError: wrong constant name foobar

Module#const_defined?

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

Module#const_missing

Invoked when a reference is made to an undefined constant in mod. It is passed a symbol for the undefined constant, and returns a value to be used for that constant. For example, consider:

def Foo.const_missing(name)
  name # return the constant name as Symbol
end

Foo::UNDEFINED_CONST    #=> :UNDEFINED_CONST: symbol returned

As the example above shows, const_missing is not required to create the missing constant in mod, though that is often a side-effect. The caller gets its return value when triggered. If the constant is also defined, further lookups won’t hit const_missing and will return the value stored in the constant as usual. Otherwise, const_missing will be invoked again.

In the next example, when a reference is made to an undefined constant, const_missing attempts to load a file whose path is the lowercase version of the constant name (thus class Fred is assumed to be in file fred.rb). If defined as a side-effect of loading the file, the method returns the value stored in the constant. This implements an autoload feature similar to Kernel#autoload and Module#autoload, though it differs in important ways.

def Object.const_missing(name)
  @looked_for ||= {}
  str_name = name.to_s
  raise "Constant not found: #{name}" if @looked_for[str_name]
  @looked_for[str_name] = 1
  file = str_name.downcase
  require file
  const_get(name, false)
end

Object#remove_instance_variable

Removes the named instance variable from obj, returning that variable’s value. The name can be passed as a symbol or as a string.

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

Gem::AvailableSet#remove_installed!

No documentation available

Gem::Command#remove_option

Remove previously defined command-line argument name.

FileUtils#remove_entry_secure

Securely removes the entry given by path, which should be the entry for a regular file, a symbolic link, or a directory.

Argument path should be interpretable as a path.

Avoids a local vulnerability that can exist in certain circumstances; see Avoiding the TOCTTOU Vulnerability.

Optional argument force specifies whether to ignore raised exceptions of StandardError and its descendants.

Related: methods for deleting.

FileUtils::remove_entry_secure

Securely removes the entry given by path, which should be the entry for a regular file, a symbolic link, or a directory.

Argument path should be interpretable as a path.

Avoids a local vulnerability that can exist in certain circumstances; see Avoiding the TOCTTOU Vulnerability.

Optional argument force specifies whether to ignore raised exceptions of StandardError and its descendants.

Related: methods for deleting.

Module#remove_class_variable

Removes the named class variable from the receiver, returning that variable’s value.

class Example
  @@var = 99
  puts remove_class_variable(:@@var)
  p(defined? @@var)
end

produces:

99
nil

Module#const_source_location

Returns the Ruby source filename and line number containing the definition of the constant specified. If the named constant is not found, nil is returned. If the constant is found, but its source location can not be extracted (constant is defined in C code), empty array is returned.

inherit specifies whether to lookup in mod.ancestors (true by default).

# test.rb:
class A         # line 1
  C1 = 1
  C2 = 2
end

module M        # line 6
  C3 = 3
end

class B < A     # line 10
  include M
  C4 = 4
end

class A # continuation of A definition
  C2 = 8 # constant redefinition; warned yet allowed
end

p B.const_source_location('C4')           # => ["test.rb", 12]
p B.const_source_location('C3')           # => ["test.rb", 7]
p B.const_source_location('C1')           # => ["test.rb", 2]

p B.const_source_location('C3', false)    # => nil  -- don't lookup in ancestors

p A.const_source_location('C2')           # => ["test.rb", 16] -- actual (last) definition place

p Object.const_source_location('B')       # => ["test.rb", 10] -- top-level constant could be looked through Object
p Object.const_source_location('A')       # => ["test.rb", 1] -- class reopening is NOT considered new definition

p B.const_source_location('A')            # => ["test.rb", 1]  -- because Object is in ancestors
p M.const_source_location('A')            # => ["test.rb", 1]  -- Object is not ancestor, but additionally checked for modules

p Object.const_source_location('A::C1')   # => ["test.rb", 2]  -- nesting is supported
p Object.const_source_location('String')  # => []  -- constant is defined in C code

Gem::Specification::remove_spec

Removes spec from the known specs.