Class: Module

Inherits:
Object show all
Defined in:
object.c,
class.c,
object.c

Overview

*********************************************************************

A <code>Module</code> 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 <code>Module#module_function</code>)

In the descriptions that follow, the parameter <i>sym</i> refers
to a symbol, which is either a quoted string or a
<code>Symbol</code> (such as <code>:name</code>).

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

Assign the module to a constant (name starting uppercase) if you want to treat it like a regular module.

Overloads:

  • #new {|mod| ... } ⇒ Object

    Yields:

    • (mod) 


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# File 'object.c', line 1695

static VALUE
rb_mod_initialize(VALUE module)
{
    if (rb_block_given_p()) {
	rb_mod_module_exec(1, &module, module);
    }
    return Qnil;
}

Class Method Details

.constants ⇒ Array .constants(inherited) ⇒ Array

In the first form, returns an array of the names of all constants accessible from the point of call. This list includes the names of all modules and classes defined in the global scope.

Module.constants.first(4)
   # => [:ARGF, :ARGV, :ArgumentError, :Array]

Module.constants.include?(:SEEK_SET)   # => false

class IO
  Module.constants.include?(:SEEK_SET) # => true
end

The second form calls the instance method constants.

Overloads:



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# File 'eval.c', line 375

static VALUE
rb_mod_s_constants(int argc, VALUE *argv, VALUE mod)
{
    const NODE *cref = rb_vm_cref();
    VALUE klass;
    VALUE cbase = 0;
    void *data = 0;

    if (argc > 0) {
	return rb_mod_constants(argc, argv, rb_cModule);
    }

    while (cref) {
	klass = cref->nd_clss;
	if (!(cref->flags & NODE_FL_CREF_PUSHED_BY_EVAL) &&
	    !NIL_P(klass)) {
	    data = rb_mod_const_at(cref->nd_clss, data);
	    if (!cbase) {
		cbase = klass;
	    }
	}
	cref = cref->nd_next;
    }

    if (cbase) {
	data = rb_mod_const_of(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:



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# File 'eval.c', line 336

static VALUE
rb_mod_nesting(void)
{
    VALUE ary = rb_ary_new();
    const NODE *cref = rb_vm_cref();

    while (cref && cref->nd_next) {
	VALUE klass = cref->nd_clss;
	if (!(cref->flags & NODE_FL_CREF_PUSHED_BY_EVAL) &&
	    !NIL_P(klass)) {
	    rb_ary_push(ary, klass);
	}
	cref = cref->nd_next;
    }
    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) 


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# File 'object.c', line 1576

static VALUE
rb_mod_lt(VALUE mod, VALUE 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) 


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# File 'object.c', line 1541

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

    if (mod == arg) return Qtrue;
    if (!CLASS_OR_MODULE_P(arg) && !RB_TYPE_P(arg, T_ICLASS)) {
	rb_raise(rb_eTypeError, "compared with non class/module");
    }
    arg = RCLASS_ORIGIN(arg);
    while (mod) {
	if (RCLASS_M_TBL_WRAPPER(mod) == RCLASS_M_TBL_WRAPPER(arg))
	    return Qtrue;
	mod = RCLASS_SUPER(mod);
    }
    /* not mod < arg; check if mod > arg */
    while (arg) {
	if (RCLASS_M_TBL_WRAPPER(arg) == RCLASS_M_TBL_WRAPPER(start))
	    return Qfalse;
	arg = RCLASS_SUPER(arg);
    }
    return Qnil;
}

#<=>(other_module) ⇒ -1, ...

Comparison—Returns -1, 0, +1 or nil depending on whether module includes other_module, they are the same, or if module is included by other_module. This is the basis for the tests in Comparable.

Returns nil if module has no relationship with other_module, if other_module is not a module, or if the two values are incomparable.

Returns:

  • (-1, 0, +1, nil) 


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# File 'object.c', line 1636

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

    if (mod == arg) return INT2FIX(0);
    if (!CLASS_OR_MODULE_P(arg)) {
	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 descendant classes to provide class-specific meaning.

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

obj = "a"
other = obj.dup

obj == other      #=> true
obj.equal? other  #=> false
obj.equal? obj    #=> true

The eql? method returns true if obj and other refer to the same hash key. This is used by Hash to test members for equality. For objects of class Object, eql? is synonymous with ==. Subclasses normally continue this tradition by aliasing eql? to their overridden == method, 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) 


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# File 'object.c', line 141

VALUE
rb_obj_equal(VALUE obj1, VALUE 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 descendants. Of limited use for modules, but can be used in case statements to classify objects by class.

Returns:

  • (Boolean) 


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# File 'object.c', line 1523

static VALUE
rb_mod_eqq(VALUE mod, VALUE 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) 


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# File 'object.c', line 1617

static VALUE
rb_mod_gt(VALUE mod, VALUE 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) 


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# File 'object.c', line 1596

static VALUE
rb_mod_ge(VALUE mod, VALUE arg)
{
    if (!CLASS_OR_MODULE_P(arg)) {
	rb_raise(rb_eTypeError, "compared with non class/module");
    }

    return rb_class_inherited_p(arg, mod);
}

#alias_method(new_name, old_name) ⇒ self (private)

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:

  • (self) 


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# File 'vm_method.c', line 1296

static VALUE
rb_mod_alias_method(VALUE mod, VALUE newname, VALUE oldname)
{
    ID oldid = rb_check_id(&oldname);
    if (!oldid) {
	rb_print_undef_str(mod, oldname);
    }
    rb_alias(mod, rb_to_id(newname), oldid);
    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:



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# File 'class.c', line 1051

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

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

#append_features(mod) ⇒ Object (private)

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.



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# File 'eval.c', line 997

static VALUE
rb_mod_append_features(VALUE module, VALUE include)
{
    if (!CLASS_OR_MODULE_P(include)) {
	Check_Type(include, T_CLASS);
    }
    rb_include_module(include, module);

    return module;
}

#attr ⇒ Object (private) 



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# File 'object.c', line 1970

VALUE
rb_mod_attr(int argc, VALUE *argv, VALUE klass)
{
    if (argc == 2 && (argv[1] == Qtrue || argv[1] == Qfalse)) {
	rb_warning("optional boolean argument is obsoleted");
	rb_attr(klass, id_for_attr(argv[0]), 1, RTEST(argv[1]), TRUE);
	return Qnil;
    }
    return rb_mod_attr_reader(argc, argv, klass);
}

#attr_accessor(symbol, ...) ⇒ nil (private) #attr_accessor(string, ...) ⇒ nil (private)

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. Also creates a method called name= to set the attribute. String arguments are converted to symbols.

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

Overloads:

  • #attr_accessor(symbol, ...) ⇒ nil

    Returns:

    • (nil)
  • #attr_accessor(string, ...) ⇒ nil

    Returns:

    • (nil) 


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# File 'object.c', line 2019

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

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

#attr_reader(symbol, ...) ⇒ nil (private) #attr(symbol, ...) ⇒ nil (private) #attr_reader(string, ...) ⇒ nil (private) #attr(string, ...) ⇒ nil (private)

Creates instance variables and corresponding methods that return the value of each instance variable. Equivalent to calling “attr:name” on each name in turn. String arguments are converted to symbols.

Overloads:

  • #attr_reader(symbol, ...) ⇒ nil

    Returns:

    • (nil)
  • #attr(symbol, ...) ⇒ nil

    Returns:

    • (nil)
  • #attr_reader(string, ...) ⇒ nil

    Returns:

    • (nil)
  • #attr(string, ...) ⇒ nil

    Returns:

    • (nil) 


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# File 'object.c', line 1959

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

    for (i=0; i<argc; i++) {
	rb_attr(klass, id_for_attr(argv[i]), TRUE, FALSE, TRUE);
    }
    return Qnil;
}

#attr_writer(symbol, ...) ⇒ nil (private) #attr_writer(string, ...) ⇒ nil (private)

Creates an accessor method to allow assignment to the attribute symbol.id2name. String arguments are converted to symbols.

Overloads:

  • #attr_writer(symbol, ...) ⇒ nil

    Returns:

    • (nil)
  • #attr_writer(string, ...) ⇒ nil

    Returns:

    • (nil) 


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# File 'object.c', line 1991

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

    for (i=0; i<argc; i++) {
	rb_attr(klass, id_for_attr(argv[i]), FALSE, TRUE, TRUE);
    }
    return Qnil;
}

#autoload ⇒ nil

Registers filename to be loaded (using Kernel::require) the first time that module (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) 


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# File 'load.c', line 1081

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

    FilePathValue(file);
    rb_autoload(mod, id, RSTRING_PTR(file));
    return Qnil;
}

#autoload?(name) ⇒ String?

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:

Returns:

  • (Boolean) 


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# File 'load.c', line 1104

static VALUE
rb_mod_autoload_p(VALUE mod, VALUE sym)
{
    ID id = rb_check_id(&sym);
    if (!id) {
	return Qnil;
    }
    return rb_autoload_p(mod, id);
}

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

Evaluates the string or block in the context of mod, except that when a block is given, constant/class variable lookup is not affected. 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:



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# File 'vm_eval.c', line 1685

VALUE
rb_mod_module_eval(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. Any arguments passed to the method will be passed to the block. This can be used if the block needs to access instance variables.

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:



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# File 'vm_eval.c', line 1713

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

#class_variable_defined?(symbol) ⇒ Boolean #class_variable_defined?(string) ⇒ Boolean

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

Overloads:

  • #class_variable_defined?(symbol) ⇒ Boolean

    Returns:

    • (Boolean)
  • #class_variable_defined?(string) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


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# File 'object.c', line 2506

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

    if (!id) {
	if (rb_is_class_name(iv)) {
	    return Qfalse;
	}
	else {
	    rb_name_error_str(iv, "`%"PRIsVALUE"' is not allowed as a class variable name",
			      QUOTE(iv));
	}
    }
    if (!rb_is_class_id(id)) {
	rb_name_error(id, "`%"PRIsVALUE"' is not allowed as a class variable name",
		      QUOTE_ID(id));
    }
    return rb_cvar_defined(obj, id);
}

#class_variable_get(symbol) ⇒ Object #class_variable_get(string) ⇒ 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 String arguments are converted to symbols.

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

Overloads:



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# File 'object.c', line 2440

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

    if (!id) {
	if (rb_is_class_name(iv)) {
	    rb_name_error_str(iv, "uninitialized class variable %"PRIsVALUE" in %"PRIsVALUE"",
			      iv, rb_class_name(obj));
	}
	else {
	    rb_name_error_str(iv, "`%"PRIsVALUE"' is not allowed as a class variable name",
			      QUOTE(iv));
	}
    }
    if (!rb_is_class_id(id)) {
	rb_name_error(id, "`%"PRIsVALUE"' is not allowed as a class variable name",
		      QUOTE_ID(id));
    }
    return rb_cvar_get(obj, id);
}

#class_variable_set(symbol, obj) ⇒ Object #class_variable_set(string, obj) ⇒ Object

Sets the class variable names by symbol to object. If the class variable name is passed as a string, that string is converted to a symbol.

class Fred
  @@foo = 99
  def foo
    @@foo
  end
end
Fred.class_variable_set(:@@foo, 101)     #=> 101
Fred.new.foo                             #=> 101

Overloads:

  • #class_variable_set(symbol, obj) ⇒ Object

    Returns:

  • #class_variable_set(string, obj) ⇒ Object

    Returns:



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# File 'object.c', line 2482

static VALUE
rb_mod_cvar_set(VALUE obj, VALUE iv, VALUE val)
{
    ID id = id_for_setter(iv, class, "`%"PRIsVALUE"' is not allowed as a class variable name");
    rb_cvar_set(obj, id, val);
    return val;
}

#class_variables(inherit = true) ⇒ Array

Returns an array of the names of class variables in mod. This includes the names of class variables in any included modules, unless the inherit parameter is set to false.

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

Returns:



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# File 'variable.c', line 2524

VALUE
rb_mod_class_variables(int argc, VALUE *argv, VALUE mod)
{
    VALUE inherit;
    st_table *tbl;

    if (argc == 0) {
	inherit = Qtrue;
    }
    else {
	rb_scan_args(argc, argv, "01", &inherit);
    }
    if (RTEST(inherit)) {
	tbl = mod_cvar_of(mod, 0);
    }
    else {
	tbl = mod_cvar_at(mod, 0);
    }
    return cvar_list(tbl);
}

#const_defined?(sym, inherit = true) ⇒ Boolean #const_defined?(str, inherit = true) ⇒ Boolean

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.)

Returns whether or not a definition is found:

Math.const_defined? "PI"   #=> true
IO.const_defined? :SYNC   #=> true
IO.const_defined? :SYNC, false   #=> false

If neither sym nor str is not a valid constant name a NameError will be raised with a warning “wrong constant name”.

Hash.const_defined? ‘foobar’ #=> NameError: wrong constant name foobar

Overloads:

  • #const_defined?(sym, inherit = true) ⇒ Boolean

    Returns:

    • (Boolean)
  • #const_defined?(str, inherit = true) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


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# File 'object.c', line 2212

static VALUE
rb_mod_const_defined(int argc, VALUE *argv, VALUE mod)
{
    VALUE name, recur;
    rb_encoding *enc;
    const char *pbeg, *p, *path, *pend;
    ID id;

    if (argc == 1) {
	name = argv[0];
	recur = Qtrue;
    }
    else {
	rb_scan_args(argc, argv, "11", &name, &recur);
    }

    if (SYMBOL_P(name)) {
	id = SYM2ID(name);
	if (!rb_is_const_id(id)) goto wrong_id;
	return RTEST(recur) ? rb_const_defined(mod, id) : rb_const_defined_at(mod, id);
    }

    path = StringValuePtr(name);
    enc = rb_enc_get(name);

    if (!rb_enc_asciicompat(enc)) {
	rb_raise(rb_eArgError, "invalid class path encoding (non ASCII)");
    }

    pbeg = p = path;
    pend = path + RSTRING_LEN(name);

    if (p >= pend || !*p) {
      wrong_name:
	rb_raise(rb_eNameError, "wrong constant name %"PRIsVALUE,
		 QUOTE(name));
    }

    if (p + 2 < pend && p[0] == ':' && p[1] == ':') {
	mod = rb_cObject;
	p += 2;
	pbeg = p;
    }

    while (p < pend) {
	VALUE part;
	long len, beglen;

	while (p < pend && *p != ':') p++;

	if (pbeg == p) goto wrong_name;

	id = rb_check_id_cstr(pbeg, len = p-pbeg, enc);
	beglen = pbeg-path;

	if (p < pend && p[0] == ':') {
	    if (p + 2 >= pend || p[1] != ':') goto wrong_name;
	    p += 2;
	    pbeg = p;
	}

	if (!id) {
	    part = rb_str_subseq(name, beglen, len);
	    OBJ_FREEZE(part);
	    if (!ISUPPER(*pbeg) || !rb_is_const_name(part)) {
		rb_name_error_str(part, "wrong constant name %"PRIsVALUE,
				  QUOTE(part));
	    }
	    else {
		return Qfalse;
	    }
	}
	if (!rb_is_const_id(id)) {
	  wrong_id:
	    rb_name_error(id, "wrong constant name %"PRIsVALUE,
			  QUOTE_ID(id));
	}
	if (RTEST(recur)) {
	    if (!rb_const_defined(mod, id))
		return Qfalse;
	    mod = rb_const_get(mod, id);
	}
	else {
	    if (!rb_const_defined_at(mod, id))
		return Qfalse;
	    mod = rb_const_get_at(mod, id);
	}
	recur = Qfalse;

	if (p < pend && !RB_TYPE_P(mod, T_MODULE) && !RB_TYPE_P(mod, T_CLASS)) {
	    rb_raise(rb_eTypeError, "%"PRIsVALUE" does not refer to class/module",
		     QUOTE(name));
	}
    }

    return Qtrue;
}

#const_get(sym, inherit = true) ⇒ Object #const_get(str, inherit = true) ⇒ Object

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 neither sym nor str 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

Overloads:

  • #const_get(sym, inherit = true) ⇒ Object

    Returns:

  • #const_get(str, inherit = true) ⇒ Object

    Returns:



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# File 'object.c', line 2070

static VALUE
rb_mod_const_get(int argc, VALUE *argv, VALUE mod)
{
    VALUE name, recur;
    rb_encoding *enc;
    const char *pbeg, *p, *path, *pend;
    ID id;

    if (argc == 1) {
	name = argv[0];
	recur = Qtrue;
    }
    else {
	rb_scan_args(argc, argv, "11", &name, &recur);
    }

    if (SYMBOL_P(name)) {
	id = SYM2ID(name);
	if (!rb_is_const_id(id)) goto wrong_id;
	return RTEST(recur) ? rb_const_get(mod, id) : rb_const_get_at(mod, id);
    }

    path = StringValuePtr(name);
    enc = rb_enc_get(name);

    if (!rb_enc_asciicompat(enc)) {
	rb_raise(rb_eArgError, "invalid class path encoding (non ASCII)");
    }

    pbeg = p = path;
    pend = path + RSTRING_LEN(name);

    if (p >= pend || !*p) {
      wrong_name:
	rb_raise(rb_eNameError, "wrong constant name %"PRIsVALUE,
		 QUOTE(name));
    }

    if (p + 2 < pend && p[0] == ':' && p[1] == ':') {
	mod = rb_cObject;
	p += 2;
	pbeg = p;
    }

    while (p < pend) {
	VALUE part;
	long len, beglen;

	while (p < pend && *p != ':') p++;

	if (pbeg == p) goto wrong_name;

	id = rb_check_id_cstr(pbeg, len = p-pbeg, enc);
	beglen = pbeg-path;

	if (p < pend && p[0] == ':') {
	    if (p + 2 >= pend || p[1] != ':') goto wrong_name;
	    p += 2;
	    pbeg = p;
	}

	if (!RB_TYPE_P(mod, T_MODULE) && !RB_TYPE_P(mod, T_CLASS)) {
	    rb_raise(rb_eTypeError, "%"PRIsVALUE" does not refer to class/module",
		     QUOTE(name));
	}

	if (!id) {
	    part = rb_str_subseq(name, beglen, len);
	    OBJ_FREEZE(part);
	    if (!ISUPPER(*pbeg) || !rb_is_const_name(part)) {
		rb_name_error_str(part, "wrong constant name %"PRIsVALUE,
				  QUOTE(part));
	    }
	    else if (!rb_method_basic_definition_p(CLASS_OF(mod), id_const_missing)) {
		id = rb_intern_str(part);
	    }
	    else {
		rb_name_error_str(part, "uninitialized constant %"PRIsVALUE"%"PRIsVALUE,
				  rb_str_subseq(name, 0, beglen),
				  QUOTE(part));
	    }
	}
	if (!rb_is_const_id(id)) {
	  wrong_id:
	    rb_name_error(id, "wrong constant name %"PRIsVALUE,
			  QUOTE_ID(id));
	}
	mod = RTEST(recur) ? rb_const_get(mod, id) : rb_const_get_at(mod, id);
    }

    return mod;
}

#const_missing(sym) ⇒ Object

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. The following code is an example of the same:

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

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

In the next example when a reference is made to an undefined constant, it attempts to load a file whose name is the lowercase version of the constant (thus class Fred is assumed to be in file fred.rb). If found, it returns the loaded class. It therefore implements an autoload feature similar to Kernel#autoload and Module#autoload.

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:



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# File 'variable.c', line 1518

VALUE
rb_mod_const_missing(VALUE klass, VALUE name)
{
    rb_frame_pop(); /* pop frame for "const_missing" */
    uninitialized_constant(klass, rb_to_id(name));

    UNREACHABLE;
}

#const_set(sym, obj) ⇒ Object #const_set(str, 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

If neither sym nor 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

Overloads:



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# File 'object.c', line 2182

static VALUE
rb_mod_const_set(VALUE mod, VALUE name, VALUE value)
{
    ID id = id_for_setter(name, const, "wrong constant name %"PRIsVALUE);
    rb_const_set(mod, id, value);
    return value;
}

#constants(inherit = true) ⇒ 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), unless the inherit parameter is set to false.

IO.constants.include?(:SYNC)        #=> true
IO.constants(false).include?(:SYNC) #=> false

Also see Module::const_defined?.

Returns:



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# File 'variable.c', line 2067

VALUE
rb_mod_constants(int argc, VALUE *argv, VALUE mod)
{
    VALUE inherit;

    if (argc == 0) {
	inherit = Qtrue;
    }
    else {
	rb_scan_args(argc, argv, "01", &inherit);
    }

    if (RTEST(inherit)) {
	return rb_const_list(rb_mod_const_of(mod, 0));
    }
    else {
	return rb_local_constants(mod);
    }
}

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

Defines an instance method in the receiver. The method parameter can be a Proc, a Method or an UnboundMethod 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) { ... } ⇒ Object

    Yields:



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# File 'proc.c', line 1619

static VALUE
rb_mod_define_method(int argc, VALUE *argv, VALUE mod)
{
    ID id;
    VALUE body;
    int noex = NOEX_PUBLIC;
    const NODE *cref = rb_vm_cref_in_context(mod);

    if (cref && cref->nd_clss == mod) {
	noex = (int)cref->nd_visi;
    }

    if (argc == 1) {
	id = rb_to_id(argv[0]);
	body = rb_block_lambda();
    }
    else {
	rb_check_arity(argc, 1, 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));
	}
    }

    if (rb_obj_is_method(body)) {
	struct METHOD *method = (struct METHOD *)DATA_PTR(body);
	VALUE rclass = method->rclass;
	if (rclass != mod && !RB_TYPE_P(rclass, T_MODULE) &&
	    !RTEST(rb_class_inherited_p(mod, rclass))) {
	    if (FL_TEST(rclass, FL_SINGLETON)) {
		rb_raise(rb_eTypeError,
			 "can't bind singleton method to a different class");
	    }
	    else {
		rb_raise(rb_eTypeError,
			 "bind argument must be a subclass of % "PRIsVALUE,
			 rb_class_name(rclass));
	    }
	}
	rb_method_entry_set(mod, id, method->me, noex);
	if (noex == NOEX_MODFUNC) {
	    rb_method_entry_set(rb_singleton_class(mod), id, method->me, NOEX_PUBLIC);
	}
    }
    else if (rb_obj_is_proc(body)) {
	rb_proc_t *proc;
	body = proc_dup(body);
	GetProcPtr(body, proc);
	if (BUILTIN_TYPE(proc->block.iseq) != T_NODE) {
	    proc->block.iseq->defined_method_id = id;
	    RB_OBJ_WRITE(proc->block.iseq->self, &proc->block.iseq->klass, mod);
	    proc->is_lambda = TRUE;
	    proc->is_from_method = TRUE;
	    proc->block.klass = mod;
	}
	rb_add_method(mod, id, VM_METHOD_TYPE_BMETHOD, (void *)body, noex);
	if (noex == NOEX_MODFUNC) {
	    rb_add_method(rb_singleton_class(mod), id, VM_METHOD_TYPE_BMETHOD, (void *)body, NOEX_PUBLIC);
	}
    }
    else {
	/* type error */
	rb_raise(rb_eTypeError, "wrong argument type (expected Proc/Method)");
    }

    return ID2SYM(id);
}

#extend_object(obj) ⇒ Object (private)

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:



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# File 'eval.c', line 1341

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

#extended ⇒ Object (private)

Not documented



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# File 'object.c', line 907

static VALUE
rb_obj_dummy(void)
{
    return Qnil;
}

#freeze ⇒ Object

Prevents further modifications to mod.

This method returns self.



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# File 'object.c', line 1506

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

#include ⇒ self

Invokes Module.append_features on each parameter in reverse order.

Returns:

  • (self) 


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# File 'eval.c', line 1015

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

    CONST_ID(id_append_features, "append_features");
    CONST_ID(id_included, "included");

    for (i = 0; i < argc; i++)
	Check_Type(argv[i], T_MODULE);
    while (argc--) {
	rb_funcall(argv[argc], id_append_features, 1, module);
	rb_funcall(argv[argc], id_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)

Returns:

  • (Boolean) 


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# File 'class.c', line 1021

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

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

#included ⇒ Object (private)

Not documented



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# File 'object.c', line 907

static VALUE
rb_obj_dummy(void)
{
    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:



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# File 'class.c', line 985

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

    for (p = RCLASS_SUPER(mod); p; p = RCLASS_SUPER(p)) {
	if (p != origin && BUILTIN_TYPE(p) == T_ICLASS) {
	    VALUE m = RBASIC(p)->klass;
	    if (RB_TYPE_P(m, T_MODULE))
		rb_ary_push(ary, m);
	}
    }
    return ary;
}

#initialize_copy ⇒ Object

:nodoc:



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# File 'class.c', line 318

VALUE
rb_mod_init_copy(VALUE clone, VALUE orig)
{
    if (RB_TYPE_P(clone, T_CLASS)) {
	class_init_copy_check(clone, orig);
    }
    rb_obj_init_copy(clone, orig);
    if (!FL_TEST(CLASS_OF(clone), FL_SINGLETON)) {
	RBASIC_SET_CLASS(clone, rb_singleton_class_clone(orig));
	rb_singleton_class_attached(RBASIC(clone)->klass, (VALUE)clone);
    }
    RCLASS_SET_SUPER(clone, RCLASS_SUPER(orig));
    RCLASS_EXT(clone)->allocator = RCLASS_EXT(orig)->allocator;
    if (RCLASS_IV_TBL(orig)) {
	st_data_t id;

	if (RCLASS_IV_TBL(clone)) {
	    st_free_table(RCLASS_IV_TBL(clone));
	}
	RCLASS_IV_TBL(clone) = rb_st_copy(clone, RCLASS_IV_TBL(orig));
	CONST_ID(id, "__tmp_classpath__");
	st_delete(RCLASS_IV_TBL(clone), &id, 0);
	CONST_ID(id, "__classpath__");
	st_delete(RCLASS_IV_TBL(clone), &id, 0);
	CONST_ID(id, "__classid__");
	st_delete(RCLASS_IV_TBL(clone), &id, 0);
    }
    if (RCLASS_CONST_TBL(orig)) {
	struct clone_const_arg arg;
	if (RCLASS_CONST_TBL(clone)) {
	    rb_free_const_table(RCLASS_CONST_TBL(clone));
	}
	RCLASS_CONST_TBL(clone) = st_init_numtable();
	arg.klass = clone;
	arg.tbl = RCLASS_CONST_TBL(clone);
	st_foreach(RCLASS_CONST_TBL(orig), clone_const_i, (st_data_t)&arg);
    }
    if (RCLASS_M_TBL(orig)) {
	if (RCLASS_M_TBL_WRAPPER(clone)) {
	    rb_free_m_tbl_wrapper(RCLASS_M_TBL_WRAPPER(clone));
	}
	RCLASS_M_TBL_INIT(clone);
	st_foreach(RCLASS_M_TBL(orig), clone_method_i, (st_data_t)clone);
    }

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

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

produces:

Hello there, Dave!



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# File 'proc.c', line 1555

static VALUE
rb_mod_instance_method(VALUE mod, VALUE vid)
{
    ID id = rb_check_id(&vid);
    if (!id) {
	rb_method_name_error(mod, vid);
    }
    return mnew(mod, Qundef, id, rb_cUnboundMethod, FALSE);
}

#instance_methods(include_super = true) ⇒ Array

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. 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:



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# File 'class.c', line 1200

VALUE
rb_class_instance_methods(int argc, VALUE *argv, VALUE mod)
{
    return class_instance_method_list(argc, argv, mod, 0, ins_methods_i);
}

#method_added ⇒ Object (private)

Not documented



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# File 'object.c', line 907

static VALUE
rb_obj_dummy(void)
{
    return Qnil;
}

#method_defined?(symbol) ⇒ Boolean #method_defined?(string) ⇒ 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. String arguments are converted to symbols.

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

Overloads:

  • #method_defined?(symbol) ⇒ Boolean

    Returns:

    • (Boolean)
  • #method_defined?(string) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


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# File 'vm_method.c', line 1017

static VALUE
rb_mod_method_defined(VALUE mod, VALUE mid)
{
    ID id = rb_check_id(&mid);
    if (!id || !rb_method_boundp(mod, id, 1)) {
	return Qfalse;
    }
    return Qtrue;

}

#method_removed ⇒ Object (private)

Not documented



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# File 'object.c', line 907

static VALUE
rb_obj_dummy(void)
{
    return Qnil;
}

#method_undefined ⇒ Object (private)

Not documented



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# File 'object.c', line 907

static VALUE
rb_obj_dummy(void)
{
    return Qnil;
}

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

Evaluates the string or block in the context of mod, except that when a block is given, constant/class variable lookup is not affected. 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:



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# File 'vm_eval.c', line 1685

VALUE
rb_mod_module_eval(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. Any arguments passed to the method will be passed to the block. This can be used if the block needs to access instance variables.

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:



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# File 'vm_eval.c', line 1713

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

#module_function(symbol, ...) ⇒ self (private) #module_function(string, ...) ⇒ self (private)

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. String arguments are converted to symbols.

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

Overloads:

  • #module_function(symbol, ...) ⇒ self

    Returns:

    • (self)
  • #module_function(string, ...) ⇒ self

    Returns:

    • (self) 


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# File 'vm_method.c', line 1521

static VALUE
rb_mod_modfunc(int argc, VALUE *argv, VALUE module)
{
    int i;
    ID id;
    const rb_method_entry_t *me;

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

    if (argc == 0) {
	SCOPE_SET(NOEX_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 (;;) {
	    me = search_method(m, id, 0);
	    if (me == 0) {
		me = search_method(rb_cObject, id, 0);
	    }
	    if (UNDEFINED_METHOD_ENTRY_P(me)) {
		rb_print_undef(module, id, 0);
	    }
	    if (me->def->type != VM_METHOD_TYPE_ZSUPER) {
		break; /* normal case: need not to follow 'super' link */
	    }
	    m = RCLASS_SUPER(m);
	    if (!m)
		break;
	}
	rb_method_entry_set(rb_singleton_class(module), id, me, NOEX_PUBLIC);
    }
    return module;
}

#name ⇒ String

Returns the name of the module mod. Returns nil for anonymous modules.

Returns:



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# File 'variable.c', line 205

VALUE
rb_mod_name(VALUE mod)
{
    int permanent;
    VALUE path = classname(mod, &permanent);

    if (!NIL_P(path)) return rb_str_dup(path);
    return path;
}

#prepend ⇒ self

Invokes Module.prepend_features on each parameter in reverse order.

Returns:

  • (self) 


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# File 'eval.c', line 1063

static VALUE
rb_mod_prepend(int argc, VALUE *argv, VALUE module)
{
    int i;
    ID id_prepend_features, id_prepended;

    CONST_ID(id_prepend_features, "prepend_features");
    CONST_ID(id_prepended, "prepended");
    for (i = 0; i < argc; i++)
	Check_Type(argv[i], T_MODULE);
    while (argc--) {
	rb_funcall(argv[argc], id_prepend_features, 1, module);
	rb_funcall(argv[argc], id_prepended, 1, module);
    }
    return module;
}

#prepend_features(mod) ⇒ Object (private)

When this module is prepended in another, Ruby calls prepend_features in this module, passing it the receiving module in mod. Ruby’s default implementation is to overlay 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#prepend.



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# File 'eval.c', line 1045

static VALUE
rb_mod_prepend_features(VALUE module, VALUE prepend)
{
    if (!CLASS_OR_MODULE_P(prepend)) {
	Check_Type(prepend, T_CLASS);
    }
    rb_prepend_module(prepend, module);

    return module;
}

#prepended ⇒ Object (private)

Not documented



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# File 'object.c', line 907

static VALUE
rb_obj_dummy(void)
{
    return Qnil;
}

#private ⇒ self (private) #private(symbol, ...) ⇒ self (private) #private(string, ...) ⇒ self (private)

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

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

Overloads:

  • #private ⇒ self

    Returns:

    • (self)
  • #private(symbol, ...) ⇒ self

    Returns:

    • (self)
  • #private(string, ...) ⇒ self

    Returns:

    • (self) 


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# File 'vm_method.c', line 1397

static VALUE
rb_mod_private(int argc, VALUE *argv, VALUE module)
{
    return set_visibility(argc, argv, module, NOEX_PRIVATE);
}

#private_class_method(symbol, ...) ⇒ Object #private_class_method(string, ...) ⇒ Object

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

String arguments are converted to symbols.

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



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# File 'vm_method.c', line 1439

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

#private_constant(symbol, ...) ⇒ Object

Makes a list of existing constants private.



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# File 'variable.c', line 2285

VALUE
rb_mod_private_constant(int argc, VALUE *argv, VALUE obj)
{
    set_const_visibility(obj, argc, argv, CONST_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:



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# File 'class.c', line 1238

VALUE
rb_class_private_instance_methods(int argc, VALUE *argv, VALUE mod)
{
    return class_instance_method_list(argc, argv, mod, 0, ins_methods_priv_i);
}

#private_method_defined?(symbol) ⇒ Boolean #private_method_defined?(string) ⇒ Boolean

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

Overloads:

  • #private_method_defined?(symbol) ⇒ Boolean

    Returns:

    • (Boolean)
  • #private_method_defined?(string) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


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# File 'vm_method.c', line 1106

static VALUE
rb_mod_private_method_defined(VALUE mod, VALUE mid)
{
    return check_definition(mod, mid, NOEX_PRIVATE);
}

#protected ⇒ self (private) #protected(symbol, ...) ⇒ self (private) #protected(string, ...) ⇒ self (private)

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

Overloads:

  • #protected ⇒ self

    Returns:

    • (self)
  • #protected(symbol, ...) ⇒ self

    Returns:

    • (self)
  • #protected(string, ...) ⇒ self

    Returns:

    • (self) 


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# File 'vm_method.c', line 1370

static VALUE
rb_mod_protected(int argc, VALUE *argv, VALUE module)
{
    return set_visibility(argc, argv, module, NOEX_PROTECTED);
}

#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:



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# File 'class.c', line 1215

VALUE
rb_class_protected_instance_methods(int argc, VALUE *argv, VALUE mod)
{
    return class_instance_method_list(argc, argv, mod, 0, ins_methods_prot_i);
}

#protected_method_defined?(symbol) ⇒ Boolean #protected_method_defined?(string) ⇒ Boolean

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

Overloads:

  • #protected_method_defined?(symbol) ⇒ Boolean

    Returns:

    • (Boolean)
  • #protected_method_defined?(string) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


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# File 'vm_method.c', line 1140

static VALUE
rb_mod_protected_method_defined(VALUE mod, VALUE mid)
{
    return check_definition(mod, mid, NOEX_PROTECTED);
}

#public ⇒ self (private) #public(symbol, ...) ⇒ self (private) #public(string, ...) ⇒ self (private)

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

Overloads:

  • #public ⇒ self

    Returns:

    • (self)
  • #public(symbol, ...) ⇒ self

    Returns:

    • (self)
  • #public(string, ...) ⇒ self

    Returns:

    • (self) 


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# File 'vm_method.c', line 1352

static VALUE
rb_mod_public(int argc, VALUE *argv, VALUE module)
{
    return set_visibility(argc, argv, module, NOEX_PUBLIC);
}

#public_class_method(symbol, ...) ⇒ Object #public_class_method(string, ...) ⇒ Object

Makes a list of existing class methods public.

String arguments are converted to symbols.



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# File 'vm_method.c', line 1413

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

#public_constant(symbol, ...) ⇒ Object

Makes a list of existing constants public.



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# File 'variable.c', line 2299

VALUE
rb_mod_public_constant(int argc, VALUE *argv, VALUE obj)
{
    set_const_visibility(obj, argc, argv, CONST_PUBLIC);
    return obj;
}

#public_instance_method(symbol) ⇒ Object

Similar to instance_method, searches public method only.



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# File 'proc.c', line 1572

static VALUE
rb_mod_public_instance_method(VALUE mod, VALUE vid)
{
    ID id = rb_check_id(&vid);
    if (!id) {
	rb_method_name_error(mod, vid);
    }
    return mnew(mod, Qundef, id, rb_cUnboundMethod, TRUE);
}

#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:



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# File 'class.c', line 1253

VALUE
rb_class_public_instance_methods(int argc, VALUE *argv, VALUE mod)
{
    return class_instance_method_list(argc, argv, mod, 0, ins_methods_pub_i);
}

#public_method_defined?(symbol) ⇒ Boolean #public_method_defined?(string) ⇒ Boolean

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

Overloads:

  • #public_method_defined?(symbol) ⇒ Boolean

    Returns:

    • (Boolean)
  • #public_method_defined?(string) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


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# File 'vm_method.c', line 1072

static VALUE
rb_mod_public_method_defined(VALUE mod, VALUE mid)
{
    return check_definition(mod, mid, NOEX_PUBLIC);
}

#refine(klass) { ... } ⇒ Object (private)

Refine klass in the receiver.

Returns an overlaid module.

Yields:



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# File 'eval.c', line 1229

static VALUE
rb_mod_refine(VALUE module, VALUE klass)
{
    VALUE refinement;
    ID id_refinements, id_activated_refinements,
       id_refined_class, id_defined_at;
    VALUE refinements, activated_refinements;
    rb_thread_t *th = GET_THREAD();
    rb_block_t *block = rb_vm_control_frame_block_ptr(th->cfp);

    if (!block) {
        rb_raise(rb_eArgError, "no block given");
    }
    if (block->proc) {
        rb_raise(rb_eArgError,
		 "can't pass a Proc as a block to Module#refine");
    }
    Check_Type(klass, T_CLASS);
    CONST_ID(id_refinements, "__refinements__");
    refinements = rb_attr_get(module, id_refinements);
    if (NIL_P(refinements)) {
	refinements = hidden_identity_hash_new();
	rb_ivar_set(module, id_refinements, refinements);
    }
    CONST_ID(id_activated_refinements, "__activated_refinements__");
    activated_refinements = rb_attr_get(module, id_activated_refinements);
    if (NIL_P(activated_refinements)) {
	activated_refinements = hidden_identity_hash_new();
	rb_ivar_set(module, id_activated_refinements,
		    activated_refinements);
    }
    refinement = rb_hash_lookup(refinements, klass);
    if (NIL_P(refinement)) {
	refinement = rb_module_new();
	RCLASS_SET_SUPER(refinement, klass);
	FL_SET(refinement, RMODULE_IS_REFINEMENT);
	CONST_ID(id_refined_class, "__refined_class__");
	rb_ivar_set(refinement, id_refined_class, klass);
	CONST_ID(id_defined_at, "__defined_at__");
	rb_ivar_set(refinement, id_defined_at, module);
	rb_hash_aset(refinements, klass, refinement);
	add_activated_refinement(activated_refinements, klass, refinement);
    }
    rb_yield_refine_block(refinement, activated_refinements);
    return refinement;
}

#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)
  p(defined? @@var)
end

produces:

99
nil

Returns:



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# File 'variable.c', line 2565

VALUE
rb_mod_remove_cvar(VALUE mod, VALUE name)
{
    const ID id = rb_check_id(&name);
    st_data_t val, n = id;

    if (!id) {
	if (rb_is_class_name(name)) {
	    rb_name_error_str(name, "class variable %"PRIsVALUE" not defined for %"PRIsVALUE"",
			      name, rb_class_name(mod));
	}
	else {
	    rb_name_error_str(name, "wrong class variable name %"PRIsVALUE"", QUOTE(name));
	}
    }
    if (!rb_is_class_id(id)) {
	rb_name_error(id, "wrong class variable name %"PRIsVALUE"", QUOTE_ID(id));
    }
    rb_check_frozen(mod);
    if (RCLASS_IV_TBL(mod) && st_delete(RCLASS_IV_TBL(mod), &n, &val)) {
	return (VALUE)val;
    }
    if (rb_cvar_defined(mod, id)) {
	rb_name_error(id, "cannot remove %"PRIsVALUE" for %"PRIsVALUE"",
		 QUOTE_ID(id), rb_class_name(mod));
    }
    rb_name_error(id, "class variable %"PRIsVALUE" not defined for %"PRIsVALUE"",
		  QUOTE_ID(id), rb_class_name(mod));

    UNREACHABLE;
}

#remove_const(sym) ⇒ Object (private)

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.

Returns:



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# File 'variable.c', line 1919

VALUE
rb_mod_remove_const(VALUE mod, VALUE name)
{
    const ID id = rb_check_id(&name);

    if (!id) {
	if (rb_is_const_name(name)) {
	    rb_name_error_str(name, "constant %"PRIsVALUE"::%"PRIsVALUE" not defined",
			      rb_class_name(mod), name);
	}
	else {
	    rb_name_error_str(name, "`%"PRIsVALUE"' is not allowed as a constant name",
			      QUOTE(name));
	}
    }
    if (!rb_is_const_id(id)) {
	rb_name_error(id, "`%"PRIsVALUE"' is not allowed as a constant name",
		      QUOTE_ID(id));
    }
    return rb_const_remove(mod, id);
}

#remove_method(symbol) ⇒ self (private) #remove_method(string) ⇒ self (private)

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

Overloads:

  • #remove_method(symbol) ⇒ self

    Returns:

    • (self)
  • #remove_method(string) ⇒ self

    Returns:

    • (self) 


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# File 'vm_method.c', line 762

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

    for (i = 0; i < argc; i++) {
	VALUE v = argv[i];
	ID id = rb_check_id(&v);
	if (!id) {
	    rb_name_error_str(v, "method `%s' not defined in %s",
			      RSTRING_PTR(v), rb_class2name(mod));
	}
	remove_method(mod, id);
    }
    return mod;
}

#singleton_class? ⇒ Boolean

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:

  • (Boolean)

Returns:

  • (Boolean) 


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# File 'object.c', line 2540

static VALUE
rb_mod_singleton_p(VALUE klass)
{
    if (RB_TYPE_P(klass, T_CLASS) && FL_TEST(klass, FL_SINGLETON))
	return Qtrue;
    return Qfalse;
}

#to_s ⇒ String Also known as: inspect

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:



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# File 'object.c', line 1462

static VALUE
rb_mod_to_s(VALUE klass)
{
    ID id_defined_at;
    VALUE refined_class, defined_at;

    if (FL_TEST(klass, FL_SINGLETON)) {
	VALUE s = rb_usascii_str_new2("#<Class:");
	VALUE v = rb_ivar_get(klass, id__attached__);

	if (CLASS_OR_MODULE_P(v)) {
	    rb_str_append(s, rb_inspect(v));
	}
	else {
	    rb_str_append(s, rb_any_to_s(v));
	}
	rb_str_cat2(s, ">");

	return s;
    }
    refined_class = rb_refinement_module_get_refined_class(klass);
    if (!NIL_P(refined_class)) {
	VALUE s = rb_usascii_str_new2("#<refinement:");

	rb_str_concat(s, rb_inspect(refined_class));
	rb_str_cat2(s, "@");
	CONST_ID(id_defined_at, "__defined_at__");
	defined_at = rb_attr_get(klass, id_defined_at);
	rb_str_concat(s, rb_inspect(defined_at));
	rb_str_cat2(s, ">");
	return s;
    }
    return rb_str_dup(rb_class_name(klass));
}

#undef_method(symbol) ⇒ self (private) #undef_method(string) ⇒ self (private)

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. String arguments are converted to symbols.

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)

Overloads:

  • #undef_method(symbol) ⇒ self

    Returns:

    • (self)
  • #undef_method(string) ⇒ self

    Returns:

    • (self) 


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# File 'vm_method.c', line 974

static VALUE
rb_mod_undef_method(int argc, VALUE *argv, VALUE mod)
{
    int i;
    for (i = 0; i < argc; i++) {
	VALUE v = argv[i];
	ID id = rb_check_id(&v);
	if (!id) {
	    rb_method_name_error(mod, v);
	}
	rb_undef(mod, id);
    }
    return mod;
}

#using ⇒ self (private)

Import class refinements from module into the current class or module definition.

Returns:

  • (self) 


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# File 'eval.c', line 1284

static VALUE
mod_using(VALUE self, VALUE module)
{
    NODE *cref = rb_vm_cref();
    rb_control_frame_t *prev_cfp = previous_frame(GET_THREAD());

    if (prev_frame_func()) {
	rb_raise(rb_eRuntimeError,
		 "Module#using is not permitted in methods");
    }
    if (prev_cfp && prev_cfp->self != self) {
	rb_raise(rb_eRuntimeError, "Module#using is not called on self");
    }
    rb_using_module(cref, module);
    return self;
}