Class: Module

Inherits:
Object show all
Defined in:
object.c

Overview

A Module is a collection of methods and constants. The methods in a module may be instance methods or module methods. Instance methods appear as methods in a class when the module is included, module methods do not. Conversely, module methods may be called without creating an encapsulating object, while instance methods may not. (See Module#module_function)

In the descriptions that follow, the parameter syml refers to a symbol, which is either a quoted string or a Symbol (such as :name).

module Mod
  include Math
  CONST = 1
  def meth
    #  ...
  end
end
Mod.class              #=> Module
Mod.constants          #=> ["E", "PI", "CONST"]
Mod.instance_methods   #=> ["meth"]

Direct Known Subclasses

Class

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#new ⇒ Object #new {|mod| ... } ⇒ Object

Creates a new anonymous module. If a block is given, it is passed the module object, and the block is evaluated in the context of this module using module_eval.

Fred = Module.new do
  def meth1
    "hello"
  end
  def meth2
    "bye"
  end
end
a = "my string"
a.extend(Fred)   #=> "my string"
a.meth1          #=> "hello"
a.meth2          #=> "bye"

Overloads:

  • #new {|mod| ... } ⇒ Object

    Yields:

    • (mod) 



# File 'object.c'

/*
 *  call-seq:
 *    Module.new                  => mod
 *    Module.new {|mod| block }   => mod
 *  
 *  Creates a new anonymous module. If a block is given, it is passed
 *  the module object, and the block is evaluated in the context of this
 *  module using <code>module_eval</code>.
 *     
 *     Fred = Module.new do
 *       def meth1
 *         "hello"
 *       end
 *       def meth2
 *         "bye"
 *       end
 *     end
 *     a = "my string"
 *     a.extend(Fred)   #=> "my string"
 *     a.meth1          #=> "hello"
 *     a.meth2          #=> "bye"
 */

static VALUE
rb_mod_initialize(module)
    VALUE module;
{
    if (rb_block_given_p()) {
    rb_mod_module_eval(0, 0, module);
    }
    return Qnil;
}

Class Method Details

.constants ⇒ Array

Returns an array of the names of all constants defined in the system. This list includes the names of all modules and classes.

p Module.constants.sort[1..5]

produces:

["ARGV", "ArgumentError", "Array", "Bignum", "Binding"]

Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     Module.constants   => array
 *  
 *  Returns an array of the names of all constants defined in the
 *  system. This list includes the names of all modules and classes.
 *     
 *     p Module.constants.sort[1..5]
 *     
 *  <em>produces:</em>
 *     
 *     ["ARGV", "ArgumentError", "Array", "Bignum", "Binding"]
 */

static VALUE
rb_mod_s_constants()
{
    NODE *cbase = ruby_cref;
    void *data = 0;

    while (cbase) {
    if (!NIL_P(cbase->nd_clss)) {
        data = rb_mod_const_at(cbase->nd_clss, data);
    }
    cbase = cbase->nd_next;
    }

    if (!NIL_P(ruby_cbase)) {
    data = rb_mod_const_of(ruby_cbase, data);
    }
    return rb_const_list(data);
}

.nesting ⇒ Array

Returns the list of Modules nested at the point of call.

module M1
  module M2
    $a = Module.nesting
  end
end
$a           #=> [M1::M2, M1]
$a[0].name   #=> "M1::M2"

Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     Module.nesting    => array
 *  
 *  Returns the list of +Modules+ nested at the point of call.
 *     
 *     module M1
 *       module M2
 *         $a = Module.nesting
 *       end
 *     end
 *     $a           #=> [M1::M2, M1]
 *     $a[0].name   #=> "M1::M2"
 */

static VALUE
rb_mod_nesting()
{
    NODE *cbase = ruby_cref;
    VALUE ary = rb_ary_new();

    while (cbase && cbase->nd_next) {
    if (!NIL_P(cbase->nd_clss)) rb_ary_push(ary, cbase->nd_clss);
    cbase = cbase->nd_next;
    }
    if (ruby_wrapper && RARRAY(ary)->len == 0) {
    rb_ary_push(ary, ruby_wrapper);
    }
    return ary;
}

Instance Method Details

#<(other) ⇒ true, ...

Returns true if mod is a subclass of other. Returns nil if there's no relationship between the two. (Think of the relationship in terms of the class definition: "class A<B" implies "A<B").

Returns:

  • (true, false, nil) 



# File 'object.c'

/*
 * call-seq:
 *   mod < other   =>  true, false, or nil
 *
 * Returns true if <i>mod</i> is a subclass of <i>other</i>. Returns 
 * <code>nil</code> if there's no relationship between the two. 
 * (Think of the relationship in terms of the class definition: 
 * "class A<B" implies "A<B").
 *
 */

static VALUE
rb_mod_lt(mod, arg)
    VALUE mod, arg;
{
    if (mod == arg) return Qfalse;
    return rb_class_inherited_p(mod, arg);
}

#<=(other) ⇒ true, ...

Returns true if mod is a subclass of other or is the same as other. Returns nil if there's no relationship between the two. (Think of the relationship in terms of the class definition: "class A<B" implies "A<B").

Returns:

  • (true, false, nil) 



# File 'object.c'

/*
 * call-seq:
 *   mod <= other   =>  true, false, or nil
 *
 * Returns true if <i>mod</i> is a subclass of <i>other</i> or
 * is the same as <i>other</i>. Returns 
 * <code>nil</code> if there's no relationship between the two. 
 * (Think of the relationship in terms of the class definition: 
 * "class A<B" implies "A<B").
 *
 */

VALUE
rb_class_inherited_p(mod, arg)
    VALUE mod, arg;
{
    VALUE start = mod;

    if (mod == arg) return Qtrue;
    switch (TYPE(arg)) {
      case T_MODULE:
      case T_CLASS:
    break;
      default:
    rb_raise(rb_eTypeError, "compared with non class/module");
    }

    if (FL_TEST(mod, FL_SINGLETON)) {
    if (RCLASS(mod)->m_tbl == RCLASS(arg)->m_tbl)
        return Qtrue;
    mod = RBASIC(mod)->klass;
    }
    while (mod) {
    if (RCLASS(mod)->m_tbl == RCLASS(arg)->m_tbl)
        return Qtrue;
    mod = RCLASS(mod)->super;
    }
    /* not mod < arg; check if mod > arg */
    while (arg) {
    if (RCLASS(arg)->m_tbl == RCLASS(start)->m_tbl)
        return Qfalse;
    arg = RCLASS(arg)->super;
    }
    return Qnil;
}

#<=>(other_mod) ⇒ -1, ...

Comparison---Returns -1 if mod includes other_mod, 0 if mod is the same as other_mod, and +1 if mod is included by other_mod or if mod has no relationship with other_mod. Returns nil if other_mod is not a module.

Returns:

  • (-1, 0, +1, nil) 



# File 'object.c'

/*
 *  call-seq:
 *     mod <=> other_mod   => -1, 0, +1, or nil
 *  
 *  Comparison---Returns -1 if <i>mod</i> includes <i>other_mod</i>, 0 if
 *  <i>mod</i> is the same as <i>other_mod</i>, and +1 if <i>mod</i> is
 *  included by <i>other_mod</i> or if <i>mod</i> has no relationship with
 *  <i>other_mod</i>. Returns <code>nil</code> if <i>other_mod</i> is
 *  not a module.
 */

static VALUE
rb_mod_cmp(mod, arg)
    VALUE mod, arg;
{
    VALUE cmp;

    if (mod == arg) return INT2FIX(0);
    switch (TYPE(arg)) {
      case T_MODULE:
      case T_CLASS:
    break;
      default:
    return Qnil;
    }

    cmp = rb_class_inherited_p(mod, arg);
    if (NIL_P(cmp)) return Qnil;
    if (cmp) {
    return INT2FIX(-1);
    }
    return INT2FIX(1);
}

#==(other) ⇒ Boolean #equal?(other) ⇒ Boolean #eql?(other) ⇒ Boolean

Equality---At the Object level, == returns true only if obj and other are the same object. Typically, this method is overridden in descendent classes to provide class-specific meaning.

Unlike ==, the equal? method should never be overridden by subclasses: it is used to determine object identity (that is, a.equal?(b) iff a is the same object as b).

The eql? method returns true if

<i>obj</i> and <i>anObject</i> have the

same value. Used by Hash to test members for equality. For objects of class Object, eql? is synonymous with ==. Subclasses normally continue this tradition, but there are exceptions. Numeric types, for example, perform type conversion across ==, but not across eql?, so:

1 == 1.0     #=> true
1.eql? 1.0   #=> false

Overloads:

  • #==(other) ⇒ Boolean

    Returns:

    • (Boolean)
  • #equal?(other) ⇒ Boolean

    Returns:

    • (Boolean)
  • #eql?(other) ⇒ Boolean

    Returns:

    • (Boolean) 



# File 'object.c'

/*
 *  call-seq:
 *     obj == other        => true or false
 *     obj.equal?(other)   => true or false
 *     obj.eql?(other)     => true or false
 *  
 *  Equality---At the <code>Object</code> level, <code>==</code> returns
 *  <code>true</code> only if <i>obj</i> and <i>other</i> are the
 *  same object. Typically, this method is overridden in descendent
 *  classes to provide class-specific meaning.
 *
 *  Unlike <code>==</code>, the <code>equal?</code> method should never be
 *  overridden by subclasses: it is used to determine object identity
 *  (that is, <code>a.equal?(b)</code> iff <code>a</code> is the same
 *  object as <code>b</code>).
 *
 *  The <code>eql?</code> method returns <code>true</code> if
    <i>obj</i> and <i>anObject</i> have the
 *  same value. Used by <code>Hash</code> to test members for equality.
 *  For objects of class <code>Object</code>, <code>eql?</code> is
 *  synonymous with <code>==</code>. Subclasses normally continue this
 *  tradition, but there are exceptions. <code>Numeric</code> types, for
 *  example, perform type conversion across <code>==</code>, but not
 *  across <code>eql?</code>, so:
 *     
 *     1 == 1.0     #=> true
 *     1.eql? 1.0   #=> false
 */

static VALUE
rb_obj_equal(obj1, obj2)
    VALUE obj1, obj2;
{
    if (obj1 == obj2) return Qtrue;
    return Qfalse;
}

#===(obj) ⇒ Boolean

Case Equality---Returns true if anObject is an instance of mod or one of mod's descendents. Of limited use for modules, but can be used in case statements to classify objects by class.

Returns:

  • (Boolean) 



# File 'object.c'

/*
 *  call-seq:
 *     mod === obj    => true or false
 *  
 *  Case Equality---Returns <code>true</code> if <i>anObject</i> is an
 *  instance of <i>mod</i> or one of <i>mod</i>'s descendents. Of
 *  limited use for modules, but can be used in <code>case</code>
 *  statements to classify objects by class.
 */

static VALUE
rb_mod_eqq(mod, arg)
    VALUE mod, arg;
{
    return rb_obj_is_kind_of(arg, mod);
}

#>(other) ⇒ true, ...

Returns true if mod is an ancestor of other. Returns nil if there's no relationship between the two. (Think of the relationship in terms of the class definition: "class A<B" implies "B>A").

Returns:

  • (true, false, nil) 



# File 'object.c'

/*
 * call-seq:
 *   mod > other   =>  true, false, or nil
 *
 * Returns true if <i>mod</i> is an ancestor of <i>other</i>. Returns 
 * <code>nil</code> if there's no relationship between the two. 
 * (Think of the relationship in terms of the class definition: 
 * "class A<B" implies "B>A").
 *
 */

static VALUE
rb_mod_gt(mod, arg)
    VALUE mod, arg;
{
    if (mod == arg) return Qfalse;
    return rb_mod_ge(mod, arg);
}

#>=(other) ⇒ true, ...

Returns true if mod is an ancestor of other, or the two modules are the same. Returns nil if there's no relationship between the two. (Think of the relationship in terms of the class definition: "class A<B" implies "B>A").

Returns:

  • (true, false, nil) 



# File 'object.c'

/*
 * call-seq:
 *   mod >= other   =>  true, false, or nil
 *
 * Returns true if <i>mod</i> is an ancestor of <i>other</i>, or the
 * two modules are the same. Returns 
 * <code>nil</code> if there's no relationship between the two. 
 * (Think of the relationship in terms of the class definition: 
 * "class A<B" implies "B>A").
 *
 */

static VALUE
rb_mod_ge(mod, arg)
    VALUE mod, arg;
{
    switch (TYPE(arg)) {
      case T_MODULE:
      case T_CLASS:
    break;
      default:
    rb_raise(rb_eTypeError, "compared with non class/module");
    }

    return rb_class_inherited_p(arg, mod);
}

#alias_method(new_name, old_name) ⇒ Module

Makes new_name a new copy of the method old_name. This can be used to retain access to methods that are overridden.

module Mod
  alias_method :orig_exit, :exit
  def exit(code=0)
    puts "Exiting with code #{code}"
    orig_exit(code)
  end
end
include Mod
exit(99)

produces:

Exiting with code 99

Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     alias_method(new_name, old_name)   => self
 *  
 *  Makes <i>new_name</i> a new copy of the method <i>old_name</i>. This can
 *  be used to retain access to methods that are overridden.
 *     
 *     module Mod
 *       alias_method :orig_exit, :exit
 *       def exit(code=0)
 *         puts "Exiting with code #{code}"
 *         orig_exit(code)
 *       end
 *     end
 *     include Mod
 *     exit(99)
 *     
 *  <em>produces:</em>
 *     
 *     Exiting with code 99
 */

static VALUE
rb_mod_alias_method(mod, newname, oldname)
    VALUE mod, newname, oldname;
{
    rb_alias(mod, rb_to_id(newname), rb_to_id(oldname));
    return mod;
}

#ancestors ⇒ Array

Returns a list of modules included in mod (including mod itself).

module Mod
  include Math
  include Comparable
end

Mod.ancestors    #=> [Mod, Comparable, Math]
Math.ancestors   #=> [Math]

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.ancestors -> array
 *  
 *  Returns a list of modules included in <i>mod</i> (including
 *  <i>mod</i> itself).
 *     
 *     module Mod
 *       include Math
 *       include Comparable
 *     end
 *     
 *     Mod.ancestors    #=> [Mod, Comparable, Math]
 *     Math.ancestors   #=> [Math]
 */

VALUE
rb_mod_ancestors(mod)
    VALUE mod;
{
    VALUE p, ary = rb_ary_new();

    for (p = mod; p; p = RCLASS(p)->super) {
	if (FL_TEST(p, FL_SINGLETON))
	    continue;
	if (BUILTIN_TYPE(p) == T_ICLASS) {
	    rb_ary_push(ary, RBASIC(p)->klass);
	}
	else {
	    rb_ary_push(ary, p);
	}
    }
    return ary;
}

#append_features(mod) ⇒ Object

When this module is included in another, Ruby calls append_features in this module, passing it the receiving module in mod. Ruby's default implementation is to add the constants, methods, and module variables of this module to mod if this module has not already been added to mod or one of its ancestors. See also Module#include.




# File 'eval.c'

/*
 *  call-seq:
 *     append_features(mod)   => mod
 *  
 *  When this module is included in another, Ruby calls
 *  <code>append_features</code> in this module, passing it the
 *  receiving module in _mod_. Ruby's default implementation is
 *  to add the constants, methods, and module variables of this module
 *  to _mod_ if this module has not already been added to
 *  _mod_ or one of its ancestors. See also <code>Module#include</code>.
 */

static VALUE
rb_mod_append_features(module, include)
    VALUE module, include;
{
    switch (TYPE(include)) {
      case T_CLASS:
      case T_MODULE:
    break;
      default:
    Check_Type(include, T_CLASS);
    break;
    }
    rb_include_module(include, module);

    return module;
}

#attr(symbol, writable = false) ⇒ nil

Defines a named attribute for this module, where the name is symbol.id2name, creating an instance variable (@name) and a corresponding access method to read it. If the optional writable argument is true, also creates a method called name= to set the attribute.

module Mod
  attr  :size, true
end

is equivalent to:

module Mod
  def size
    @size
  end
  def size=(val)
    @size = val
  end
end

Returns:

  • (nil) 



# File 'object.c'

/*
 *  call-seq:
 *     attr(symbol, writable=false)    => nil
 *  
 *  Defines a named attribute for this module, where the name is
 *  <i>symbol.</i><code>id2name</code>, creating an instance variable
 *  (<code>@name</code>) and a corresponding access method to read it.
 *  If the optional <i>writable</i> argument is <code>true</code>, also
 *  creates a method called <code>name=</code> to set the attribute.
 *     
 *     module Mod
 *       attr  :size, true
 *     end
 *     
 *  <em>is equivalent to:</em>
 *     
 *     module Mod
 *       def size
 *         @size
 *       end
 *       def size=(val)
 *         @size = val
 *       end
 *     end
 */

static VALUE
rb_mod_attr(argc, argv, klass)
    int argc;
    VALUE *argv;
    VALUE klass;
{
    VALUE name, pub;

    rb_scan_args(argc, argv, "11", &name, &pub);
    rb_attr(klass, rb_to_id(name), 1, RTEST(pub), Qtrue);
    return Qnil;
}

#attr_accessor(symbol, ...) ⇒ nil

Equivalent to calling "attrsymbol, true" on each symbol in turn.

module Mod
  attr_accessor(:one, :two)
end
Mod.instance_methods.sort   #=> ["one", "one=", "two", "two="]

Returns:

  • (nil) 



# File 'object.c'

/*
 *  call-seq:
 *     attr_accessor(symbol, ...)    => nil
 *  
 *  Equivalent to calling ``<code>attr</code><i>symbol</i><code>,
 *  true</code>'' on each <i>symbol</i> in turn.
 *     
 *     module Mod
 *       attr_accessor(:one, :two)
 *     end
 *     Mod.instance_methods.sort   #=> ["one", "one=", "two", "two="]
 */

static VALUE
rb_mod_attr_accessor(argc, argv, klass)
    int argc;
    VALUE *argv;
    VALUE klass;
{
    int i;

    for (i=0; i<argc; i++) {
    rb_attr(klass, rb_to_id(argv[i]), 1, 1, Qtrue);
    }
    return Qnil;
}

#attr_reader(symbol, ...) ⇒ nil

Creates instance variables and corresponding methods that return the value of each instance variable. Equivalent to calling "attr:name" on each name in turn.

Returns:

  • (nil) 



# File 'object.c'

/*
 *  call-seq:
 *     attr_reader(symbol, ...)    => nil
 *  
 *  Creates instance variables and corresponding methods that return the
 *  value of each instance variable. Equivalent to calling
 *  ``<code>attr</code><i>:name</i>'' on each name in turn.
 */

static VALUE
rb_mod_attr_reader(argc, argv, klass)
    int argc;
    VALUE *argv;
    VALUE klass;
{
    int i;

    for (i=0; i<argc; i++) {
    rb_attr(klass, rb_to_id(argv[i]), 1, 0, Qtrue);
    }
    return Qnil;
}

#attr_writer(symbol, ...) ⇒ nil

Creates an accessor method to allow assignment to the attribute aSymbol.id2name.

Returns:

  • (nil) 



# File 'object.c'

/*
 *  call-seq:
 *      attr_writer(symbol, ...)    => nil
 *  
 *  Creates an accessor method to allow assignment to the attribute
 *  <i>aSymbol</i><code>.id2name</code>.
 */

static VALUE
rb_mod_attr_writer(argc, argv, klass)
    int argc;
    VALUE *argv;
    VALUE klass;
{
    int i;

    for (i=0; i<argc; i++) {
    rb_attr(klass, rb_to_id(argv[i]), 0, 1, Qtrue);
    }
    return Qnil;
}

#autoload(name, filename) ⇒ nil

Registers filename to be loaded (using Kernel::require) the first time that name (which may be a String or a symbol) is accessed in the namespace of mod.

module A
end
A.autoload(:B, "b")
A::B.doit            # autoloads "b"

Returns:

  • (nil) 



# File 'eval.c'

/*
 *  call-seq:
 *     mod.autoload(name, filename)   => nil
 *
 *  Registers _filename_ to be loaded (using <code>Kernel::require</code>) 
 *  the first time that _name_ (which may be a <code>String</code> or
 *  a symbol) is accessed in the namespace of _mod_.
 *
 *     module A
 *     end
 *     A.autoload(:B, "b")
 *     A::B.doit            # autoloads "b"
 */

static VALUE
rb_mod_autoload(mod, sym, file)
    VALUE mod;
    VALUE sym;
    VALUE file;
{
    ID id = rb_to_id(sym);

    Check_SafeStr(file);
    rb_autoload(mod, id, RSTRING(file)->ptr);
    return Qnil;
}

#autoload?(name) ⇒ nil

Returns filename to be loaded if name is registered as autoload in the namespace of mod.

module A
end
A.autoload(:B, "b")
A.autoload?(:B)            # => "b"

Returns:

  • (nil) 



# File 'eval.c'

/*
 *  call-seq:
 *     mod.autoload?(name)   => String or nil
 *
 *  Returns _filename_ to be loaded if _name_ is registered as
 *  +autoload+ in the namespace of _mod_.
 *
 *     module A
 *     end
 *     A.autoload(:B, "b")
 *     A.autoload?(:B)            # => "b"
 */

static VALUE
rb_mod_autoload_p(mod, sym)
    VALUE mod, sym;
{
    return rb_autoload_p(mod, rb_to_id(sym));
}

#class_eval(string[, filename [, lineno]]) ⇒ Object #module_eval { ... } ⇒ Object

Evaluates the string or block in the context of mod. This can be used to add methods to a class. module_eval returns the result of evaluating its argument. The optional filename and lineno parameters set the text for error messages.

class Thing
end
a = %q{def hello() "Hello there!" end}
Thing.module_eval(a)
puts Thing.new.hello()
Thing.module_eval("invalid code", "dummy", 123)

produces:

Hello there!
dummy:123:in `module_eval': undefined local variable
    or method `code' for Thing:Class

Overloads:

  • #class_eval(string[, filename [, lineno]]) ⇒ Object

    Returns:

  • #module_eval { ... } ⇒ Object

    Yields:

    Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     mod.class_eval(string [, filename [, lineno]])  => obj
 *     mod.module_eval {|| block }                     => obj
 *  
 *  Evaluates the string or block in the context of _mod_. This can
 *  be used to add methods to a class. <code>module_eval</code> returns
 *  the result of evaluating its argument. The optional _filename_
 *  and _lineno_ parameters set the text for error messages.
 *     
 *     class Thing
 *     end
 *     a = %q{def hello() "Hello there!" end}
 *     Thing.module_eval(a)
 *     puts Thing.new.hello()
 *     Thing.module_eval("invalid code", "dummy", 123)
 *     
 *  <em>produces:</em>
 *     
 *     Hello there!
 *     dummy:123:in `module_eval': undefined local variable
 *         or method `code' for Thing:Class
 */

VALUE
rb_mod_module_eval(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    return specific_eval(argc, argv, mod, mod);
}

#module_exec(arg...) {|var...| ... } ⇒ Object #class_exec(arg...) {|var...| ... } ⇒ Object

Evaluates the given block in the context of the class/module. The method defined in the block will belong to the receiver.

class Thing
end
Thing.class_exec{
  def hello() "Hello there!" end
}
puts Thing.new.hello()

produces:

Hello there!

Overloads:

  • #module_exec(arg...) {|var...| ... } ⇒ Object

    Yields:

    • (var...)

    Returns:

  • #class_exec(arg...) {|var...| ... } ⇒ Object

    Yields:

    • (var...)

    Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     mod.module_exec(arg...) {|var...| block }       => obj
 *     mod.class_exec(arg...) {|var...| block }        => obj
 *
 *  Evaluates the given block in the context of the class/module.
 *  The method defined in the block will belong to the receiver.
 *
 *     class Thing
 *     end
 *     Thing.class_exec{
 *       def hello() "Hello there!" end
 *     }
 *     puts Thing.new.hello()
 *
 *  <em>produces:</em>
 *
 *     Hello there!
 */

VALUE
rb_mod_module_exec(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    return yield_under(mod, mod, rb_ary_new4(argc, argv));
}

#class_variable_defined?(symbol) ⇒ Boolean

Returns true if the given class variable is defined in obj.

class Fred
  @@foo = 99
end
Fred.class_variable_defined?(:@@foo)    #=> true
Fred.class_variable_defined?(:@@bar)    #=> false

Returns:

  • (Boolean) 



# File 'object.c'

/*
 *  call-seq:
 *     obj.class_variable_defined?(symbol)    => true or false
 *
 *  Returns <code>true</code> if the given class variable is defined
 *  in <i>obj</i>.
 *
 *     class Fred
 *       @@foo = 99
 *     end
 *     Fred.class_variable_defined?(:@@foo)    #=> true
 *     Fred.class_variable_defined?(:@@bar)    #=> false
 */

static VALUE
rb_mod_cvar_defined(obj, iv)
    VALUE obj, iv;
{
    ID id = rb_to_id(iv);

    if (!rb_is_class_id(id)) {
    rb_name_error(id, "`%s' is not allowed as a class variable name", rb_id2name(id));
    }
    return rb_cvar_defined(obj, id);
}

#class_variable_get(symbol) ⇒ Object

Returns the value of the given class variable (or throws a NameError exception). The @@ part of the variable name should be included for regular class variables

class Fred
  @@foo = 99
end

def Fred.foo
  class_variable_get(:@@foo)     #=> 99
end

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.class_variable_get(symbol)    => obj
 *  
 *  Returns the value of the given class variable (or throws a
 *  <code>NameError</code> exception). The <code>@@</code> part of the
 *  variable name should be included for regular class variables
 *     
 *     class Fred
 *       @@foo = 99
 *     end
 *
 *     def Fred.foo
 *       class_variable_get(:@@foo)     #=> 99
 *     end
 */

static VALUE
rb_mod_cvar_get(obj, iv)
    VALUE obj, iv;
{
    ID id = rb_to_id(iv);

    if (!rb_is_class_id(id)) {
    rb_name_error(id, "`%s' is not allowed as a class variable name", rb_id2name(id));
    }
    return rb_cvar_get(obj, id);
}

#class_variable_set(symbol, obj) ⇒ Object

Sets the class variable names by symbol to object.

class Fred
  @@foo = 99
  def foo
    @@foo
  end
end

def Fred.foo
  class_variable_set(:@@foo, 101)      #=> 101
end
Fred.foo
Fred.new.foo                             #=> 101

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     obj.class_variable_set(symbol, obj)    => obj
 *  
 *  Sets the class variable names by <i>symbol</i> to
 *  <i>object</i>.
 *     
 *     class Fred
 *       @@foo = 99
 *       def foo
 *         @@foo
 *       end
 *     end
 *
 *     def Fred.foo
 *       class_variable_set(:@@foo, 101)      #=> 101
 *     end
 *     Fred.foo
 *     Fred.new.foo                             #=> 101
 */

static VALUE
rb_mod_cvar_set(obj, iv, val)
    VALUE obj, iv, val;
{
    ID id = rb_to_id(iv);

    if (!rb_is_class_id(id)) {
    rb_name_error(id, "`%s' is not allowed as a class variable name", rb_id2name(id));
    }
    rb_cvar_set(obj, id, val, Qfalse);
    return val;
}

#class_variables ⇒ Array

Returns an array of the names of class variables in mod and the ancestors of mod.

class One
  @@var1 = 1
end
class Two < One
  @@var2 = 2
end
One.class_variables   #=> ["@@var1"]
Two.class_variables   #=> ["@@var2", "@@var1"]

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.class_variables   => array
 *  
 *  Returns an array of the names of class variables in <i>mod</i> and
 *  the ancestors of <i>mod</i>.
 *     
 *     class One
 *       @@var1 = 1
 *     end
 *     class Two < One
 *       @@var2 = 2
 *     end
 *     One.class_variables   #=> ["@@var1"]
 *     Two.class_variables   #=> ["@@var2", "@@var1"]
 */

VALUE
rb_mod_class_variables(obj)
    VALUE obj;
{
    VALUE ary = rb_ary_new();

    for (;;) {
	if (RCLASS(obj)->iv_tbl) {
	    st_foreach_safe(RCLASS(obj)->iv_tbl, cv_i, ary);
	}
	obj = RCLASS(obj)->super;
	if (!obj) break;
    }
    return ary;
}

#const_defined?(sym) ⇒ Boolean

Returns true if a constant with the given name is defined by mod.

Math.const_defined? "PI"   #=> true

Returns:

  • (Boolean) 



# File 'object.c'

/*
 *  call-seq:
 *     mod.const_defined?(sym)   => true or false
 *  
 *  Returns <code>true</code> if a constant with the given name is
 *  defined by <i>mod</i>.
 *     
 *     Math.const_defined? "PI"   #=> true
 */

static VALUE
rb_mod_const_defined(mod, name)
    VALUE mod, name;
{
    ID id = rb_to_id(name);

    if (!rb_is_const_id(id)) {
    rb_name_error(id, "wrong constant name %s", rb_id2name(id));
    }
    return rb_const_defined_at(mod, id);
}

#const_get(sym) ⇒ Object

Returns the value of the named constant in mod.

Math.const_get(:PI)   #=> 3.14159265358979

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.const_get(sym)    => obj
 *  
 *  Returns the value of the named constant in <i>mod</i>.
 *     
 *     Math.const_get(:PI)   #=> 3.14159265358979
 */

static VALUE
rb_mod_const_get(mod, name)
    VALUE mod, name;
{
    ID id = rb_to_id(name);

    if (!rb_is_const_id(id)) {
    rb_name_error(id, "wrong constant name %s", rb_id2name(id));
    }
    return rb_const_get(mod, id);
}

#const_missing(sym) ⇒ Object

Invoked when a reference is made to an undefined constant in

<i>mod</i>. It is passed a symbol for the undefined constant, and
returns a value to be used for that constant. The
following code is a (very bad) example: if reference is made to
an undefined constant, it attempts to load a file whose name is
the lowercase version of the constant (thus class <code>Fred</code> is
assumed to be in file <code>fred.rb</code>). If found, it returns the
value of the loaded class. It therefore implements a perverse
kind of autoload facility.

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

Returns:




# File 'object.c'

/*
 * call-seq:
 *    mod.const_missing(sym)    => obj
 *
 *  Invoked when a reference is made to an undefined constant in
 *  <i>mod</i>. It is passed a symbol for the undefined constant, and
 *  returns a value to be used for that constant. The
 *  following code is a (very bad) example: if reference is made to
 *  an undefined constant, it attempts to load a file whose name is
 *  the lowercase version of the constant (thus class <code>Fred</code> is
 *  assumed to be in file <code>fred.rb</code>). If found, it returns the
 *  value of the loaded class. It therefore implements a perverse
 *  kind of autoload facility.
 *  
 *    def Object.const_missing(name)
 *      @looked_for ||= {}
 *      str_name = name.to_s
 *      raise "Class not found: #{name}" if @looked_for[str_name]
 *      @looked_for[str_name] = 1
 *      file = str_name.downcase
 *      require file
 *      klass = const_get(name)
 *      return klass if klass
 *      raise "Class not found: #{name}"
 *    end
 *  
 */

VALUE
rb_mod_const_missing(klass, name)
    VALUE klass, name;
{
    ruby_frame = ruby_frame->prev; /* pop frame for "const_missing" */
    uninitialized_constant(klass, rb_to_id(name));
    return Qnil;		/* not reached */
}

#const_set(sym, obj) ⇒ Object

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

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.const_set(sym, obj)    => obj
 *  
 *  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
 */

static VALUE
rb_mod_const_set(mod, name, value)
    VALUE mod, name, value;
{
    ID id = rb_to_id(name);

    if (!rb_is_const_id(id)) {
    rb_name_error(id, "wrong constant name %s", rb_id2name(id));
    }
    rb_const_set(mod, id, value);
    return value;
}

#constants ⇒ Array

Returns an array of the names of the constants accessible in mod. This includes the names of constants in any included modules (example at start of section).

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.constants    => array
 *  
 *  Returns an array of the names of the constants accessible in
 *  <i>mod</i>. This includes the names of constants in any included
 *  modules (example at start of section).
 */

VALUE
rb_mod_constants(mod)
    VALUE mod;
{
    return rb_const_list(rb_mod_const_of(mod, 0));
}

#define_method(symbol, method) ⇒ Object #define_method(symbol) { ... } ⇒ Proc

Defines an instance method in the receiver. The method parameter can be a Proc or Method object. If a block is specified, it is used as the method body. This block is evaluated using instance_eval, a point that is tricky to demonstrate because define_method is private. (This is why we resort to the send hack in this example.)

class A
  def fred
    puts "In Fred"
  end
  def create_method(name, &block)
    self.class.send(:define_method, name, &block)
  end
  define_method(:wilma) { puts "Charge it!" }
end
class B < A
  define_method(:barney, instance_method(:fred))
end
a = B.new
a.barney
a.wilma
a.create_method(:betty) { p self }
a.betty

produces:

In Fred
Charge it!
#<B:0x401b39e8>

Overloads:

  • #define_method(symbol) { ... } ⇒ Proc

    Yields:

    Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     define_method(symbol, method)     => new_method
 *     define_method(symbol) { block }   => proc
 *  
 *  Defines an instance method in the receiver. The _method_
 *  parameter can be a +Proc+ or +Method+ object.
 *  If a block is specified, it is used as the method body. This block
 *  is evaluated using <code>instance_eval</code>, a point that is
 *  tricky to demonstrate because <code>define_method</code> is private.
 *  (This is why we resort to the +send+ hack in this example.)
 *     
 *     class A
 *       def fred
 *         puts "In Fred"
 *       end
 *       def create_method(name, &block)
 *         self.class.send(:define_method, name, &block)
 *       end
 *       define_method(:wilma) { puts "Charge it!" }
 *     end
 *     class B < A
 *       define_method(:barney, instance_method(:fred))
 *     end
 *     a = B.new
 *     a.barney
 *     a.wilma
 *     a.create_method(:betty) { p self }
 *     a.betty
 *     
 *  <em>produces:</em>
 *     
 *     In Fred
 *     Charge it!
 *     #<B:0x401b39e8>
 */

static VALUE
rb_mod_define_method(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    ID id;
    VALUE body, orig;
    NODE *node;
    int noex;

    if (argc == 1) {
    id = rb_to_id(argv[0]);
    body = proc_lambda();
    }
    else if (argc == 2) {
    id = rb_to_id(argv[0]);
    body = argv[1];
    if (!rb_obj_is_method(body) && !rb_obj_is_proc(body)) {
        rb_raise(rb_eTypeError, "wrong argument type %s (expected Proc/Method)",
             rb_obj_classname(body));
    }
    }
    else {
    rb_raise(rb_eArgError, "wrong number of arguments (%d for 1)", argc);
    }
    orig = body;
    if (RDATA(body)->dmark == (RUBY_DATA_FUNC)bm_mark) {
    node = NEW_DMETHOD(method_unbind(body));
    }
    else if (RDATA(body)->dmark == (RUBY_DATA_FUNC)blk_mark) {
    struct BLOCK *block;

    body = proc_clone(body);
    Data_Get_Struct(body, struct BLOCK, block);
    block->frame.last_func = id;
    block->frame.orig_func = id;
    block->frame.last_class = mod;
    node = NEW_BMETHOD(body);
    }
    else {
    /* type error */
    rb_raise(rb_eTypeError, "wrong argument type (expected Proc/Method)");
    }

    noex = NOEX_PUBLIC;
    if (ruby_cbase == mod) {
    if (SCOPE_TEST(SCOPE_PRIVATE)) {
        noex = NOEX_PRIVATE;
    }
    else if (SCOPE_TEST(SCOPE_PROTECTED)) {
        noex = NOEX_PROTECTED;
    }
    }
    rb_add_method(mod, id, node, noex);
    return orig;
}

#extend_object(obj) ⇒ Object

Extends the specified object by adding this module's constants and methods (which are added as singleton methods). This is the callback method used by Object#extend.

module Picky
  def Picky.extend_object(o)
    if String === o
      puts "Can't add Picky to a String"
    else
      puts "Picky added to #{o.class}"
      super
    end
  end
end
(s = Array.new).extend Picky  # Call Object.extend
(s = "quick brown fox").extend Picky

produces:

Picky added to Array
Can't add Picky to a String

Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     extend_object(obj)    => obj
 *  
 *  Extends the specified object by adding this module's constants and
 *  methods (which are added as singleton methods). This is the callback
 *  method used by <code>Object#extend</code>.
 *     
 *     module Picky
 *       def Picky.extend_object(o)
 *         if String === o
 *           puts "Can't add Picky to a String"
 *         else
 *           puts "Picky added to #{o.class}"
 *           super
 *         end
 *       end
 *     end
 *     (s = Array.new).extend Picky  # Call Object.extend
 *     (s = "quick brown fox").extend Picky
 *     
 *  <em>produces:</em>
 *     
 *     Picky added to Array
 *     Can't add Picky to a String
 */

static VALUE
rb_mod_extend_object(mod, obj)
    VALUE mod, obj;
{
    rb_extend_object(obj, mod);
    return obj;
}

#extended ⇒ Object

Not documented




# File 'object.c'

/*
 * Not documented
 */

static VALUE
rb_obj_dummy()
{
    return Qnil;
}

#freeze ⇒ Object

Prevents further modifications to mod.




# File 'object.c'

/*
 *  call-seq:
 *     mod.freeze
 *  
 *  Prevents further modifications to <i>mod</i>.
 */

static VALUE
rb_mod_freeze(mod)
    VALUE mod;
{
    rb_mod_to_s(mod);
    return rb_obj_freeze(mod);
}

#include ⇒ Module

Invokes Module.append_features on each parameter in turn.

Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     include(module, ...)    => self
 *  
 *  Invokes <code>Module.append_features</code> on each parameter in turn.
 */

static VALUE
rb_mod_include(argc, argv, module)
    int argc;
    VALUE *argv;
    VALUE module;
{
    int i;

    for (i=0; i<argc; i++) Check_Type(argv[i], T_MODULE);
    while (argc--) {
    rb_funcall(argv[argc], rb_intern("append_features"), 1, module);
    rb_funcall(argv[argc], rb_intern("included"), 1, module);
    }
    return module;
}

#include? ⇒ Boolean

Returns true if module is included in mod or one of mod's ancestors.

module A
end
class B
  include A
end
class C < B
end
B.include?(A)   #=> true
C.include?(A)   #=> true
A.include?(A)   #=> false

Returns:

  • (Boolean) 



# File 'object.c'

/*
 *  call-seq:
 *     mod.include?(module)    => true or false
 *  
 *  Returns <code>true</code> if <i>module</i> is included in
 *  <i>mod</i> or one of <i>mod</i>'s ancestors.
 *     
 *     module A
 *     end
 *     class B
 *       include A
 *     end
 *     class C < B
 *     end
 *     B.include?(A)   #=> true
 *     C.include?(A)   #=> true
 *     A.include?(A)   #=> false
 */

VALUE
rb_mod_include_p(mod, mod2)
    VALUE mod;
    VALUE mod2;
{
    VALUE p;

    Check_Type(mod2, T_MODULE);
    for (p = RCLASS(mod)->super; p; p = RCLASS(p)->super) {
	if (BUILTIN_TYPE(p) == T_ICLASS) {
	    if (RBASIC(p)->klass == mod2) return Qtrue;
	}
    }
    return Qfalse;
}

#included(othermod) ⇒ Object

Callback invoked whenever the receiver is included in another module or class. This should be used in preference to Module.append_features if your code wants to perform some action when a module is included in another.

module A
  def A.included(mod)
    puts "#{self} included in #{mod}"
  end
end
module Enumerable
  include A
end




# File 'object.c'

/*
 * Not documented
 */

static VALUE
rb_obj_dummy()
{
    return Qnil;
}

#included_modules ⇒ Array

Returns the list of modules included in mod.

module Mixin
end

module Outer
  include Mixin
end

Mixin.included_modules   #=> []
Outer.included_modules   #=> [Mixin]

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.included_modules -> array
 *  
 *  Returns the list of modules included in <i>mod</i>.
 *     
 *     module Mixin
 *     end
 *     
 *     module Outer
 *       include Mixin
 *     end
 *     
 *     Mixin.included_modules   #=> []
 *     Outer.included_modules   #=> [Mixin]
 */

VALUE
rb_mod_included_modules(mod)
    VALUE mod;
{
    VALUE ary = rb_ary_new();
    VALUE p;

    for (p = RCLASS(mod)->super; p; p = RCLASS(p)->super) {
	if (BUILTIN_TYPE(p) == T_ICLASS) {
	    rb_ary_push(ary, RBASIC(p)->klass);
	}
    }
    return ary;
}

#initialize_copy ⇒ Object

:nodoc:




# File 'object.c'

/* :nodoc: */
VALUE
rb_mod_init_copy(clone, orig)
    VALUE clone, orig;
{
    rb_obj_init_copy(clone, orig);
    if (!FL_TEST(CLASS_OF(clone), FL_SINGLETON)) {
	RBASIC(clone)->klass = RBASIC(orig)->klass;
	RBASIC(clone)->klass = rb_singleton_class_clone(clone);
    }
    RCLASS(clone)->super = RCLASS(orig)->super;
    if (RCLASS(orig)->iv_tbl) {
	ID id;

	RCLASS(clone)->iv_tbl = st_copy(RCLASS(orig)->iv_tbl);
	id = rb_intern("__classpath__");
	st_delete(RCLASS(clone)->iv_tbl, (st_data_t*)&id, 0);
	id = rb_intern("__classid__");
	st_delete(RCLASS(clone)->iv_tbl, (st_data_t*)&id, 0);
    }
    if (RCLASS(orig)->m_tbl) {
	struct clone_method_data data;

	data.tbl = RCLASS(clone)->m_tbl = st_init_numtable();
	data.klass = (VALUE)clone;

	st_foreach(RCLASS(orig)->m_tbl, clone_method, (st_data_t)&data);
    }

    return clone;
}

#instance_method(symbol) ⇒ Object

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_byte {|b| Dispatcher[b].bind(self).call }
  end
end

interpreter = Interpreter.new
interpreter.interpret('dave')

produces:

Hello there, Dave!




# File 'eval.c'

/*
 *  call-seq:
 *     mod.instance_method(symbol)   => unbound_method
 *  
 *  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_byte {|b| Dispatcher[b].bind(self).call }
 *       end
 *     end
 *     
 *     
 *     interpreter = Interpreter.new
 *     interpreter.interpret('dave')
 *     
 *  <em>produces:</em>
 *     
 *     Hello there, Dave!
 */

static VALUE
rb_mod_method(mod, vid)
    VALUE mod;
    VALUE vid;
{
    return mnew(mod, Qundef, rb_to_id(vid), rb_cUnboundMethod);
}

#instance_methods(include_super = true) ⇒ Array

Returns an array containing the names of public instance methods in the receiver. For a module, these are the public methods; for a class, they are the instance (not singleton) methods. With no argument, or with an argument that is false, the instance methods in mod are returned, otherwise the methods in mod and mod's superclasses are returned.

module A
  def method1()  end
end
class B
  def method2()  end
end
class C < B
  def method3()  end
end

A.instance_methods                #=> ["method1"]
B.instance_methods(false)         #=> ["method2"]
C.instance_methods(false)         #=> ["method3"]
C.instance_methods(true).length   #=> 43

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.instance_methods(include_super=true)   => array
 *  
 *  Returns an array containing the names of public instance methods in
 *  the receiver. For a module, these are the public methods; for a
 *  class, they are the instance (not singleton) methods. With no
 *  argument, or with an argument that is <code>false</code>, the
 *  instance methods in <i>mod</i> are returned, otherwise the methods
 *  in <i>mod</i> and <i>mod</i>'s superclasses are returned.
 *     
 *     module A
 *       def method1()  end
 *     end
 *     class B
 *       def method2()  end
 *     end
 *     class C < B
 *       def method3()  end
 *     end
 *     
 *     A.instance_methods                #=> ["method1"]
 *     B.instance_methods(false)         #=> ["method2"]
 *     C.instance_methods(false)         #=> ["method3"]
 *     C.instance_methods(true).length   #=> 43
 */

VALUE
rb_class_instance_methods(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    return class_instance_method_list(argc, argv, mod, ins_methods_i);
}

#method_added ⇒ Object

Not documented




# File 'object.c'

/*
 * Not documented
 */

static VALUE
rb_obj_dummy()
{
    return Qnil;
}

#method_defined?(symbol) ⇒ Boolean

Returns true if the named method is defined by mod (or its included modules and, if mod is a class, its ancestors). Public and protected methods are matched.

module A
  def method1()  end
end
class B
  def method2()  end
end
class C < B
  include A
  def method3()  end
end

A.method_defined? :method1    #=> true
C.method_defined? "method1"   #=> true
C.method_defined? "method2"   #=> true
C.method_defined? "method3"   #=> true
C.method_defined? "method4"   #=> false

Returns:

  • (Boolean) 



# File 'eval.c'

/*
 *  call-seq:
 *     mod.method_defined?(symbol)    => true or false
 *  
 *  Returns +true+ if the named method is defined by
 *  _mod_ (or its included modules and, if _mod_ is a class,
 *  its ancestors). Public and protected methods are matched.
 *     
 *     module A
 *       def method1()  end
 *     end
 *     class B
 *       def method2()  end
 *     end
 *     class C < B
 *       include A
 *       def method3()  end
 *     end
 *     
 *     A.method_defined? :method1    #=> true
 *     C.method_defined? "method1"   #=> true
 *     C.method_defined? "method2"   #=> true
 *     C.method_defined? "method3"   #=> true
 *     C.method_defined? "method4"   #=> false
 */

static VALUE
rb_mod_method_defined(mod, mid)
    VALUE mod, mid;
{
    return rb_method_boundp(mod, rb_to_id(mid), 1);
}

#method_removed ⇒ Object

Not documented




# File 'object.c'

/*
 * Not documented
 */

static VALUE
rb_obj_dummy()
{
    return Qnil;
}

#method_undefined ⇒ Object

Not documented




# File 'object.c'

/*
 * Not documented
 */

static VALUE
rb_obj_dummy()
{
    return Qnil;
}

#class_eval(string[, filename [, lineno]]) ⇒ Object #module_eval { ... } ⇒ Object

Evaluates the string or block in the context of mod. This can be used to add methods to a class. module_eval returns the result of evaluating its argument. The optional filename and lineno parameters set the text for error messages.

class Thing
end
a = %q{def hello() "Hello there!" end}
Thing.module_eval(a)
puts Thing.new.hello()
Thing.module_eval("invalid code", "dummy", 123)

produces:

Hello there!
dummy:123:in `module_eval': undefined local variable
    or method `code' for Thing:Class

Overloads:

  • #class_eval(string[, filename [, lineno]]) ⇒ Object

    Returns:

  • #module_eval { ... } ⇒ Object

    Yields:

    Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     mod.class_eval(string [, filename [, lineno]])  => obj
 *     mod.module_eval {|| block }                     => obj
 *  
 *  Evaluates the string or block in the context of _mod_. This can
 *  be used to add methods to a class. <code>module_eval</code> returns
 *  the result of evaluating its argument. The optional _filename_
 *  and _lineno_ parameters set the text for error messages.
 *     
 *     class Thing
 *     end
 *     a = %q{def hello() "Hello there!" end}
 *     Thing.module_eval(a)
 *     puts Thing.new.hello()
 *     Thing.module_eval("invalid code", "dummy", 123)
 *     
 *  <em>produces:</em>
 *     
 *     Hello there!
 *     dummy:123:in `module_eval': undefined local variable
 *         or method `code' for Thing:Class
 */

VALUE
rb_mod_module_eval(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    return specific_eval(argc, argv, mod, mod);
}

#module_exec(arg...) {|var...| ... } ⇒ Object #class_exec(arg...) {|var...| ... } ⇒ Object

Evaluates the given block in the context of the class/module. The method defined in the block will belong to the receiver.

class Thing
end
Thing.class_exec{
  def hello() "Hello there!" end
}
puts Thing.new.hello()

produces:

Hello there!

Overloads:

  • #module_exec(arg...) {|var...| ... } ⇒ Object

    Yields:

    • (var...)

    Returns:

  • #class_exec(arg...) {|var...| ... } ⇒ Object

    Yields:

    • (var...)

    Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     mod.module_exec(arg...) {|var...| block }       => obj
 *     mod.class_exec(arg...) {|var...| block }        => obj
 *
 *  Evaluates the given block in the context of the class/module.
 *  The method defined in the block will belong to the receiver.
 *
 *     class Thing
 *     end
 *     Thing.class_exec{
 *       def hello() "Hello there!" end
 *     }
 *     puts Thing.new.hello()
 *
 *  <em>produces:</em>
 *
 *     Hello there!
 */

VALUE
rb_mod_module_exec(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    return yield_under(mod, mod, rb_ary_new4(argc, argv));
}

#module_function(symbol, ...) ⇒ Module

Creates module functions for the named methods. These functions may be called with the module as a receiver, and also become available as instance methods to classes that mix in the module. Module functions are copies of the original, and so may be changed independently. The instance-method versions are made private. If used with no arguments, subsequently defined methods become module functions.

module Mod
  def one
    "This is one"
  end
  module_function :one
end
class Cls
  include Mod
  def callOne
    one
  end
end
Mod.one     #=> "This is one"
c = Cls.new
c.callOne   #=> "This is one"
module Mod
  def one
    "This is the new one"
  end
end
Mod.one     #=> "This is one"
c.callOne   #=> "This is the new one"

Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     module_function(symbol, ...)    => self
 *  
 *  Creates module functions for the named methods. These functions may
 *  be called with the module as a receiver, and also become available
 *  as instance methods to classes that mix in the module. Module
 *  functions are copies of the original, and so may be changed
 *  independently. The instance-method versions are made private. If
 *  used with no arguments, subsequently defined methods become module
 *  functions.
 *     
 *     module Mod
 *       def one
 *         "This is one"
 *       end
 *       module_function :one
 *     end
 *     class Cls
 *       include Mod
 *       def callOne
 *         one
 *       end
 *     end
 *     Mod.one     #=> "This is one"
 *     c = Cls.new
 *     c.callOne   #=> "This is one"
 *     module Mod
 *       def one
 *         "This is the new one"
 *       end
 *     end
 *     Mod.one     #=> "This is one"
 *     c.callOne   #=> "This is the new one"
 */

static VALUE
rb_mod_modfunc(argc, argv, module)
    int argc;
    VALUE *argv;
    VALUE module;
{
    int i;
    ID id;
    NODE *body;

    if (TYPE(module) != T_MODULE) {
    rb_raise(rb_eTypeError, "module_function must be called for modules");
    }

    secure_visibility(module);
    if (argc == 0) {
    SCOPE_SET(SCOPE_MODFUNC);
    return module;
    }

    set_method_visibility(module, argc, argv, NOEX_PRIVATE);
    for (i=0; i<argc; i++) {
    VALUE m = module;

    id = rb_to_id(argv[i]);
    for (;;) {
        body = search_method(m, id, &m);
        if (body == 0) {
        body = search_method(rb_cObject, id, &m);
        }
        if (body == 0 || body->nd_body == 0) {
        print_undef(module, id);
        }
        if (nd_type(body->nd_body) != NODE_ZSUPER) {
        break;        /* normal case: need not to follow 'super' link */
        }
        m = RCLASS(m)->super;
        if (!m) break;
    }
    rb_add_method(rb_singleton_class(module), id, body->nd_body, NOEX_PUBLIC);
    }
    return module;
}

#name ⇒ String

Returns the name of the module mod.

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.name    => string
 *  
 *  Returns the name of the module <i>mod</i>.
 */

VALUE
rb_mod_name(mod)
    VALUE mod;
{
    VALUE path = classname(mod);

    if (!NIL_P(path)) return rb_str_dup(path);
    return rb_str_new(0,0);
}

#private ⇒ Module #private(symbol, ...) ⇒ Module

With no arguments, sets the default visibility for subsequently defined methods to private. With arguments, sets the named methods to have private visibility.

module Mod
  def a()  end
  def b()  end
  private
  def c()  end
  private :a
end
Mod.private_instance_methods   #=> ["a", "c"]

Overloads:




# File 'eval.c'

/*
 *  call-seq:
 *     private                 => self
 *     private(symbol, ...)    => self
 *  
 *  With no arguments, sets the default visibility for subsequently
 *  defined methods to private. With arguments, sets the named methods
 *  to have private visibility.
 *     
 *     module Mod
 *       def a()  end
 *       def b()  end
 *       private
 *       def c()  end
 *       private :a
 *     end
 *     Mod.private_instance_methods   #=> ["a", "c"]
 */

static VALUE
rb_mod_private(argc, argv, module)
    int argc;
    VALUE *argv;
    VALUE module;
{
    secure_visibility(module);
    if (argc == 0) {
    SCOPE_SET(SCOPE_PRIVATE);
    }
    else {
    set_method_visibility(module, argc, argv, NOEX_PRIVATE);
    }
    return module;
}

#private_class_method(symbol, ...) ⇒ Object

Makes existing class methods private. Often used to hide the default constructor new.

class SimpleSingleton  # Not thread safe
  private_class_method :new
  def SimpleSingleton.create(*args, &block)
    @me = new(*args, &block) if ! @me
    @me
  end
end




# File 'eval.c'

/*
 *  call-seq:
 *     mod.private_class_method(symbol, ...)   => mod
 *  
 *  Makes existing class methods private. Often used to hide the default
 *  constructor <code>new</code>.
 *     
 *     class SimpleSingleton  # Not thread safe
 *       private_class_method :new
 *       def SimpleSingleton.create(*args, &block)
 *         @me = new(*args, &block) if ! @me
 *         @me
 *       end
 *     end
 */

static VALUE
rb_mod_private_method(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    set_method_visibility(CLASS_OF(obj), argc, argv, NOEX_PRIVATE);
    return obj;
}

#private_instance_methods(include_super = true) ⇒ Array

Returns a list of the private instance methods defined in mod. If the optional parameter is not false, the methods of any ancestors are included.

module Mod
  def method1()  end
  private :method1
  def method2()  end
end
Mod.instance_methods           #=> ["method2"]
Mod.private_instance_methods   #=> ["method1"]

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.private_instance_methods(include_super=true)    => array
 *  
 *  Returns a list of the private instance methods defined in
 *  <i>mod</i>. If the optional parameter is not <code>false</code>, the
 *  methods of any ancestors are included.
 *     
 *     module Mod
 *       def method1()  end
 *       private :method1
 *       def method2()  end
 *     end
 *     Mod.instance_methods           #=> ["method2"]
 *     Mod.private_instance_methods   #=> ["method1"]
 */

VALUE
rb_class_private_instance_methods(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    return class_instance_method_list(argc, argv, mod, ins_methods_priv_i);
}

#private_method_defined?(symbol) ⇒ Boolean

Returns true if the named private method is defined by _ mod_ (or its included modules and, if mod is a class, its ancestors).

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:

  • (Boolean) 



# File 'eval.c'

/*
 *  call-seq:
 *     mod.private_method_defined?(symbol)    => true or false
 *  
 *  Returns +true+ if the named private method is defined by
 *  _ mod_ (or its included modules and, if _mod_ is a class,
 *  its ancestors).
 *     
 *     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
 */

static VALUE
rb_mod_private_method_defined(mod, mid)
    VALUE mod, mid;
{
    ID id = rb_to_id(mid);
    int noex;

    if (rb_get_method_body(&mod, &id, &noex)) {
    if (VISI_CHECK(noex, NOEX_PRIVATE))
        return Qtrue;
    }
    return Qfalse;
}

#protected ⇒ Module #protected(symbol, ...) ⇒ Module

With no arguments, sets the default visibility for subsequently defined methods to protected. With arguments, sets the named methods to have protected visibility.

Overloads:




# File 'eval.c'

/*
 *  call-seq:
 *     protected                => self
 *     protected(symbol, ...)   => self
 *  
 *  With no arguments, sets the default visibility for subsequently
 *  defined methods to protected. With arguments, sets the named methods
 *  to have protected visibility.
 */

static VALUE
rb_mod_protected(argc, argv, module)
    int argc;
    VALUE *argv;
    VALUE module;
{
    secure_visibility(module);
    if (argc == 0) {
    SCOPE_SET(SCOPE_PROTECTED);
    }
    else {
    set_method_visibility(module, argc, argv, NOEX_PROTECTED);
    }
    return module;
}

#protected_instance_methods(include_super = true) ⇒ Array

Returns a list of the protected instance methods defined in mod. If the optional parameter is not false, the methods of any ancestors are included.

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.protected_instance_methods(include_super=true)   => array
 *  
 *  Returns a list of the protected instance methods defined in
 *  <i>mod</i>. If the optional parameter is not <code>false</code>, the
 *  methods of any ancestors are included.
 */

VALUE
rb_class_protected_instance_methods(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    return class_instance_method_list(argc, argv, mod, ins_methods_prot_i);
}

#protected_method_defined?(symbol) ⇒ Boolean

Returns true if the named protected method is defined by mod (or its included modules and, if mod is a class, its ancestors).

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

Returns:

  • (Boolean) 



# File 'eval.c'

/*
 *  call-seq:
 *     mod.protected_method_defined?(symbol)   => true or false
 *  
 *  Returns +true+ if the named protected method is defined
 *  by _mod_ (or its included modules and, if _mod_ is a
 *  class, its ancestors).
 *     
 *     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
 */

static VALUE
rb_mod_protected_method_defined(mod, mid)
    VALUE mod, mid;
{
    ID id = rb_to_id(mid);
    int noex;

    if (rb_get_method_body(&mod, &id, &noex)) {
    if (VISI_CHECK(noex, NOEX_PROTECTED))
        return Qtrue;
    }
    return Qfalse;
}

#public ⇒ Module #public(symbol, ...) ⇒ Module

With no arguments, sets the default visibility for subsequently defined methods to public. With arguments, sets the named methods to have public visibility.

Overloads:




# File 'eval.c'

/*
 *  call-seq:
 *     public                 => self
 *     public(symbol, ...)    => self
 *  
 *  With no arguments, sets the default visibility for subsequently
 *  defined methods to public. With arguments, sets the named methods to
 *  have public visibility.
 */

static VALUE
rb_mod_public(argc, argv, module)
    int argc;
    VALUE *argv;
    VALUE module;
{
    secure_visibility(module);
    if (argc == 0) {
    SCOPE_SET(SCOPE_PUBLIC);
    }
    else {
    set_method_visibility(module, argc, argv, NOEX_PUBLIC);
    }
    return module;
}

#public_class_method(symbol, ...) ⇒ Object

Makes a list of existing class methods public.




# File 'eval.c'

/*
 *  call-seq:
 *     mod.public_class_method(symbol, ...)    => mod
 *  
 *  Makes a list of existing class methods public.
 */

static VALUE
rb_mod_public_method(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    set_method_visibility(CLASS_OF(obj), argc, argv, NOEX_PUBLIC);
    return obj;
}

#public_instance_methods(include_super = true) ⇒ Array

Returns a list of the public instance methods defined in mod. If the optional parameter is not false, the methods of any ancestors are included.

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     mod.public_instance_methods(include_super=true)   => array
 *  
 *  Returns a list of the public instance methods defined in <i>mod</i>.
 *  If the optional parameter is not <code>false</code>, the methods of
 *  any ancestors are included.
 */

VALUE
rb_class_public_instance_methods(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    return class_instance_method_list(argc, argv, mod, ins_methods_pub_i);
}

#public_method_defined?(symbol) ⇒ Boolean

Returns true if the named public method is defined by mod (or its included modules and, if mod is a class, its ancestors).

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:

  • (Boolean) 



# File 'eval.c'

/*
 *  call-seq:
 *     mod.public_method_defined?(symbol)   => true or false
 *  
 *  Returns +true+ if the named public method is defined by
 *  _mod_ (or its included modules and, if _mod_ is a class,
 *  its ancestors).
 *     
 *     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
 */

static VALUE
rb_mod_public_method_defined(mod, mid)
    VALUE mod, mid;
{
    ID id = rb_to_id(mid);
    int noex;

    if (rb_get_method_body(&mod, &id, &noex)) {
    if (VISI_CHECK(noex, NOEX_PUBLIC))
        return Qtrue;
    }
    return Qfalse;
}

#remove_class_variable(sym) ⇒ Object

Removes the definition of the sym, returning that constant's value.

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

produces:

99
nil

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     remove_class_variable(sym)    => obj
 *  
 *  Removes the definition of the <i>sym</i>, returning that
 *  constant's value.
 *     
 *     class Dummy
 *       @@var = 99
 *       puts @@var
 *       remove_class_variable(:@@var)
 *       puts(defined? @@var)
 *     end
 *     
 *  <em>produces:</em>
 *     
 *     99
 *     nil
 */

VALUE
rb_mod_remove_cvar(mod, name)
    VALUE mod, name;
{
    ID id = rb_to_id(name);
    VALUE val;

    if (!rb_is_class_id(id)) {
	rb_name_error(id, "wrong class variable name %s", rb_id2name(id));
    }
    if (!OBJ_TAINTED(mod) && rb_safe_level() >= 4)
	rb_raise(rb_eSecurityError, "Insecure: can't remove class variable");
    if (OBJ_FROZEN(mod)) rb_error_frozen("class/module");

    if (RCLASS(mod)->iv_tbl && st_delete(ROBJECT(mod)->iv_tbl, (st_data_t*)&id, &val)) {
	return val;
    }
    if (rb_cvar_defined(mod, id)) {
	rb_name_error(id, "cannot remove %s for %s",
		 rb_id2name(id), rb_class2name(mod));
    }
    rb_name_error(id, "class variable %s not defined for %s",
		  rb_id2name(id), rb_class2name(mod));
    return Qnil;		/* not reached */
}

#remove_const(sym) ⇒ Object

Removes the definition of the given constant, returning that constant's value. Predefined classes and singleton objects (such as true) cannot be removed.

Returns:




# File 'object.c'

/*
 *  call-seq:
 *     remove_const(sym)   => obj
 *  
 *  Removes the definition of the given constant, returning that
 *  constant's value. Predefined classes and singleton objects (such as
 *  <i>true</i>) cannot be removed.
 */

VALUE
rb_mod_remove_const(mod, name)
    VALUE mod, name;
{
    ID id = rb_to_id(name);
    VALUE val;

    if (!rb_is_const_id(id)) {
	rb_name_error(id, "`%s' is not allowed as a constant name", rb_id2name(id));
    }
    if (!OBJ_TAINTED(mod) && rb_safe_level() >= 4)
	rb_raise(rb_eSecurityError, "Insecure: can't remove constant");
    if (OBJ_FROZEN(mod)) rb_error_frozen("class/module");

    if (RCLASS(mod)->iv_tbl && st_delete(ROBJECT(mod)->iv_tbl, (st_data_t*)&id, &val)) {
	if (val == Qundef) {
	    autoload_delete(mod, id);
	    val = Qnil;
	}
	return val;
    }
    if (rb_const_defined_at(mod, id)) {
	rb_name_error(id, "cannot remove %s::%s",
		 rb_class2name(mod), rb_id2name(id));
    }
    rb_name_error(id, "constant %s::%s not defined",
		  rb_class2name(mod), rb_id2name(id));
    return Qnil;		/* not reached */
}

#remove_method(symbol) ⇒ Module

Removes the method identified by symbol from the current class. For an example, see Module.undef_method.

Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     remove_method(symbol)   => self
 *  
 *  Removes the method identified by _symbol_ from the current
 *  class. For an example, see <code>Module.undef_method</code>.
 */

static VALUE
rb_mod_remove_method(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    int i;

    for (i=0; i<argc; i++) {
    remove_method(mod, rb_to_id(argv[i]));
    }
    return mod;
}

#to_s ⇒ String

Return a string representing this module or class. For basic classes and modules, this is the name. For singletons, we show information on the thing we're attached to as well.

Returns:




# File 'object.c'

/*
 * call-seq:
 *   mod.to_s   => string
 *
 * Return a string representing this module or class. For basic
 * classes and modules, this is the name. For singletons, we
 * show information on the thing we're attached to as well.
 */

static VALUE
rb_mod_to_s(klass)
    VALUE klass;

{
    if (FL_TEST(klass, FL_SINGLETON)) {
    VALUE s = rb_str_new2("#<");
    VALUE v = rb_iv_get(klass, "__attached__");

    rb_str_cat2(s, "Class:");
    switch (TYPE(v)) {
      case T_CLASS: case T_MODULE:
        rb_str_append(s, rb_inspect(v));
        break;
      default:
        rb_str_append(s, rb_any_to_s(v));
        break;
    }
    rb_str_cat2(s, ">");

    return s;
    }
    return rb_str_dup(rb_class_name(klass));
}

#undef_method(symbol) ⇒ Module

Prevents the current class from responding to calls to the named method. Contrast this with remove_method, which deletes the method from the particular class; Ruby will still search superclasses and mixed-in modules for a possible receiver.

class Parent
  def hello
    puts "In parent"
  end
end
class Child < Parent
  def hello
    puts "In child"
  end
end

c = Child.new
c.hello

class Child
  remove_method :hello  # remove from child, still in parent
end
c.hello

class Child
  undef_method :hello   # prevent any calls to 'hello'
end
c.hello

produces:

In child
In parent
prog.rb:23: undefined method `hello' for #<Child:0x401b3bb4> (NoMethodError)

Returns:




# File 'eval.c'

/*
 *  call-seq:
 *     undef_method(symbol)    => self
 *  
 *  Prevents the current class from responding to calls to the named
 *  method. Contrast this with <code>remove_method</code>, which deletes
 *  the method from the particular class; Ruby will still search
 *  superclasses and mixed-in modules for a possible receiver.
 *     
 *     class Parent
 *       def hello
 *         puts "In parent"
 *       end
 *     end
 *     class Child < Parent
 *       def hello
 *         puts "In child"
 *       end
 *     end
 *     
 *     
 *     c = Child.new
 *     c.hello
 *     
 *     
 *     class Child
 *       remove_method :hello  # remove from child, still in parent
 *     end
 *     c.hello
 *     
 *     
 *     class Child
 *       undef_method :hello   # prevent any calls to 'hello'
 *     end
 *     c.hello
 *     
 *  <em>produces:</em>
 *     
 *     In child
 *     In parent
 *     prog.rb:23: undefined method `hello' for #<Child:0x401b3bb4> (NoMethodError)
 */

static VALUE
rb_mod_undef_method(argc, argv, mod)
    int argc;
    VALUE *argv;
    VALUE mod;
{
    int i;

    for (i=0; i<argc; i++) {
    rb_undef(mod, rb_to_id(argv[i]));
    }
    return mod;
}