class Module
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 sym 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 #=> [:CONST, :PI, :E] Mod.instance_methods #=> [:meth]
Public Class Methods
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.
static VALUE
rb_mod_s_constants(int argc, VALUE *argv, VALUE mod)
{
const rb_cref_t *cref = rb_vm_cref();
VALUE klass;
VALUE cbase = 0;
void *data = 0;
if (argc > 0 || mod != rb_cModule) {
return rb_mod_constants(argc, argv, mod);
}
while (cref) {
klass = CREF_CLASS(cref);
if (!CREF_PUSHED_BY_EVAL(cref) &&
!NIL_P(klass)) {
data = rb_mod_const_at(CREF_CLASS(cref), data);
if (!cbase) {
cbase = klass;
}
}
cref = CREF_NEXT(cref);
}
if (cbase) {
data = rb_mod_const_of(cbase, data);
}
return rb_const_list(data);
}
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(VALUE _)
{
VALUE ary = rb_ary_new();
const rb_cref_t *cref = rb_vm_cref();
while (cref && CREF_NEXT(cref)) {
VALUE klass = CREF_CLASS(cref);
if (!CREF_PUSHED_BY_EVAL(cref) &&
!NIL_P(klass)) {
rb_ary_push(ary, klass);
}
cref = CREF_NEXT(cref);
}
return ary;
}
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 like 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.
static VALUE
rb_mod_initialize(VALUE module)
{
return rb_mod_initialize_exec(module);
}
Returns an array of all modules used in the current scope. The ordering of modules in the resulting array is not defined.
module A refine Object do end end module B refine Object do end end using A using B p Module.used_modules
produces:
[B, A]
static VALUE
rb_mod_s_used_modules(VALUE _)
{
const rb_cref_t *cref = rb_vm_cref();
VALUE ary = rb_ary_new();
while (cref) {
if (!NIL_P(CREF_REFINEMENTS(cref))) {
rb_hash_foreach(CREF_REFINEMENTS(cref), used_modules_i, ary);
}
cref = CREF_NEXT(cref);
}
return rb_funcall(ary, rb_intern("uniq"), 0);
}
Returns an array of all modules used in the current scope. The ordering of modules in the resulting array is not defined.
module A refine Object do end end module B refine Object do end end using A using B p Module.used_refinements
produces:
[#<refinement:Object@B>, #<refinement:Object@A>]
static VALUE
rb_mod_s_used_refinements(VALUE _)
{
const rb_cref_t *cref = rb_vm_cref();
VALUE ary = rb_ary_new();
while (cref) {
if (!NIL_P(CREF_REFINEMENTS(cref))) {
rb_hash_foreach(CREF_REFINEMENTS(cref), used_refinements_i, ary);
}
cref = CREF_NEXT(cref);
}
return ary;
}
Public Instance Methods
Returns true if mod is a subclass of other. Returns false if mod is the same as other or 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 “A < B”.)
static VALUE
rb_mod_lt(VALUE mod, VALUE arg)
{
if (mod == arg) return Qfalse;
return rb_class_inherited_p(mod, arg);
}
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”.)
VALUE
rb_class_inherited_p(VALUE mod, VALUE arg)
{
if (mod == arg) return Qtrue;
if (RB_TYPE_P(arg, T_CLASS) && RB_TYPE_P(mod, T_CLASS)) {
// comparison between classes
size_t mod_depth = RCLASS_SUPERCLASS_DEPTH(mod);
size_t arg_depth = RCLASS_SUPERCLASS_DEPTH(arg);
if (arg_depth < mod_depth) {
// check if mod < arg
return RCLASS_SUPERCLASSES(mod)[arg_depth] == arg ?
Qtrue :
Qnil;
}
else if (arg_depth > mod_depth) {
// check if mod > arg
return RCLASS_SUPERCLASSES(arg)[mod_depth] == mod ?
Qfalse :
Qnil;
}
else {
// Depths match, and we know they aren't equal: no relation
return Qnil;
}
}
else {
if (!CLASS_OR_MODULE_P(arg) && !RB_TYPE_P(arg, T_ICLASS)) {
rb_raise(rb_eTypeError, "compared with non class/module");
}
if (class_search_ancestor(mod, RCLASS_ORIGIN(arg))) {
return Qtrue;
}
/* not mod < arg; check if mod > arg */
if (class_search_ancestor(arg, mod)) {
return Qfalse;
}
return Qnil;
}
}
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.
Returns nil if module has no relationship with other_module, if other_module is not a module, or if the two values are incomparable.
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);
}
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 any pair of objects where eql? returns true, the hash value of both objects must be equal. So any subclass that overrides eql? should also override hash appropriately.
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
VALUE
rb_obj_equal(VALUE obj1, VALUE obj2)
{
return RBOOL(obj1 == obj2);
}
Case Equality—Returns true if obj is an instance of mod or an instance of one of mod’s descendants. Of limited use for modules, but can be used in case statements to classify objects by class.
static VALUE
rb_mod_eqq(VALUE mod, VALUE arg)
{
return rb_obj_is_kind_of(arg, mod);
}
Returns true if mod is an ancestor of other. Returns false if mod is the same as other or mod is a descendant 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”.)
static VALUE
rb_mod_gt(VALUE mod, VALUE arg)
{
if (mod == arg) return Qfalse;
return rb_mod_ge(mod, arg);
}
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”.)
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);
}
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 #=> :orig_exit def exit(code=0) puts "Exiting with code #{code}" orig_exit(code) end end include Mod exit(99)
produces:
Exiting with code 99
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);
}
VALUE id = rb_to_id(newname);
rb_alias(mod, id, oldid);
return ID2SYM(id);
}
Returns a list of modules included/prepended in mod (including mod itself).
module Mod include Math include Comparable prepend Enumerable end Mod.ancestors #=> [Enumerable, Mod, Comparable, Math] Math.ancestors #=> [Math] Enumerable.ancestors #=> [Enumerable]
VALUE
rb_mod_ancestors(VALUE mod)
{
VALUE p, ary = rb_ary_new();
VALUE refined_class = Qnil;
if (BUILTIN_TYPE(mod) == T_MODULE && FL_TEST(mod, RMODULE_IS_REFINEMENT)) {
refined_class = rb_refinement_module_get_refined_class(mod);
}
for (p = mod; p; p = RCLASS_SUPER(p)) {
if (p == refined_class) break;
if (p != RCLASS_ORIGIN(p)) continue;
if (BUILTIN_TYPE(p) == T_ICLASS) {
rb_ary_push(ary, METACLASS_OF(p));
}
else {
rb_ary_push(ary, p);
}
}
return ary;
}
The first form is equivalent to attr_reader. The second form is equivalent to attr_accessor(name) but deprecated. The last form is equivalent to attr_reader(name) but deprecated. Returns an array of defined method names as symbols.
VALUE
rb_mod_attr(int argc, VALUE *argv, VALUE klass)
{
if (argc == 2 && (argv[1] == Qtrue || argv[1] == Qfalse)) {
ID id = id_for_attr(klass, argv[0]);
VALUE names = rb_ary_new();
rb_category_warning(RB_WARN_CATEGORY_DEPRECATED, "optional boolean argument is obsoleted");
rb_attr(klass, id, 1, RTEST(argv[1]), TRUE);
rb_ary_push(names, ID2SYM(id));
if (argv[1] == Qtrue) rb_ary_push(names, ID2SYM(rb_id_attrset(id)));
return names;
}
return rb_mod_attr_reader(argc, argv, klass);
}
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. Returns an array of defined method names as symbols.
module Mod attr_accessor(:one, :two) #=> [:one, :one=, :two, :two=] end Mod.instance_methods.sort #=> [:one, :one=, :two, :two=]
static VALUE
rb_mod_attr_accessor(int argc, VALUE *argv, VALUE klass)
{
int i;
VALUE names = rb_ary_new2(argc * 2);
for (i=0; i<argc; i++) {
ID id = id_for_attr(klass, argv[i]);
rb_attr(klass, id, TRUE, TRUE, TRUE);
rb_ary_push(names, ID2SYM(id));
rb_ary_push(names, ID2SYM(rb_id_attrset(id)));
}
return names;
}
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. Returns an array of defined method names as symbols.
static VALUE
rb_mod_attr_reader(int argc, VALUE *argv, VALUE klass)
{
int i;
VALUE names = rb_ary_new2(argc);
for (i=0; i<argc; i++) {
ID id = id_for_attr(klass, argv[i]);
rb_attr(klass, id, TRUE, FALSE, TRUE);
rb_ary_push(names, ID2SYM(id));
}
return names;
}
Creates an accessor method to allow assignment to the attribute symbol.id2name. String arguments are converted to symbols. Returns an array of defined method names as symbols.
static VALUE
rb_mod_attr_writer(int argc, VALUE *argv, VALUE klass)
{
int i;
VALUE names = rb_ary_new2(argc);
for (i=0; i<argc; i++) {
ID id = id_for_attr(klass, argv[i]);
rb_attr(klass, id, FALSE, TRUE, TRUE);
rb_ary_push(names, ID2SYM(rb_id_attrset(id)));
}
return names;
}
Registers _filename_ to be loaded (using Kernel::require) the first time that _const_ (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"
If const in mod is defined as autoload, the file name to be loaded is replaced with filename. If const is defined but not as autoload, does nothing.
static VALUE
rb_mod_autoload(VALUE mod, VALUE sym, VALUE file)
{
ID id = rb_to_id(sym);
FilePathValue(file);
rb_autoload_str(mod, id, file);
return Qnil;
}
Returns filename to be loaded if name is registered as autoload in the namespace of mod or one of its ancestors.
module A end A.autoload(:B, "b") A.autoload?(:B) #=> "b"
If inherit is false, the lookup only checks the autoloads in the receiver:
class A autoload :CONST, "const.rb" end class B < A end B.autoload?(:CONST) #=> "const.rb", found in A (ancestor) B.autoload?(:CONST, false) #=> nil, not found in B itself
static VALUE
rb_mod_autoload_p(int argc, VALUE *argv, VALUE mod)
{
int recur = (rb_check_arity(argc, 1, 2) == 1) ? TRUE : RTEST(argv[1]);
VALUE sym = argv[0];
ID id = rb_check_id(&sym);
if (!id) {
return Qnil;
}
return rb_autoload_at_p(mod, id, recur);
}
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
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!
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
static VALUE
rb_mod_cvar_defined(VALUE obj, VALUE iv)
{
ID id = id_for_var(obj, iv, class);
if (!id) {
return Qfalse;
}
return rb_cvar_defined(obj, id);
}
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
static VALUE
rb_mod_cvar_get(VALUE obj, VALUE iv)
{
ID id = id_for_var(obj, iv, class);
if (!id) {
rb_name_err_raise("uninitialized class variable %1$s in %2$s",
obj, iv);
}
return rb_cvar_get(obj, id);
}
Sets the class variable named by symbol to the given 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
static VALUE
rb_mod_cvar_set(VALUE obj, VALUE iv, VALUE val)
{
ID id = id_for_var(obj, iv, class);
if (!id) id = rb_intern_str(iv);
rb_cvar_set(obj, id, val);
return val;
}
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] Two.class_variables(false) #=> [:@@var2]
VALUE
rb_mod_class_variables(int argc, const VALUE *argv, VALUE mod)
{
bool inherit = true;
st_table *tbl;
if (rb_check_arity(argc, 0, 1)) inherit = RTEST(argv[0]);
if (inherit) {
tbl = mod_cvar_of(mod, 0);
}
else {
tbl = mod_cvar_at(mod, 0);
}
return cvar_list(tbl);
}
Says whether mod or its ancestors have a constant with the given name:
Float.const_defined?(:EPSILON) #=> true, found in Float itself Float.const_defined?("String") #=> true, found in Object (ancestor) BasicObject.const_defined?(:Hash) #=> false
If mod is a Module, additionally Object and its ancestors are checked:
Math.const_defined?(:String) #=> true, found in Object
In each of the checked classes or modules, if the constant is not present but there is an autoload for it, true is returned directly without autoloading:
module Admin autoload :User, 'admin/user' end Admin.const_defined?(:User) #=> true
If the constant is not found the callback const_missing is not called and the method returns false.
If inherit is false, the lookup only checks the constants in the receiver:
IO.const_defined?(:SYNC) #=> true, found in File::Constants (ancestor) IO.const_defined?(:SYNC, false) #=> false, not found in IO itself
In this case, the same logic for autoloading applies.
If the argument is not a valid constant name a NameError is raised with the message “wrong constant name name”:
Hash.const_defined? 'foobar' #=> NameError: wrong constant name foobar
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;
rb_check_arity(argc, 1, 2);
name = argv[0];
recur = (argc == 1) ? Qtrue : argv[1];
if (SYMBOL_P(name)) {
if (!rb_is_const_sym(name)) goto wrong_name;
id = rb_check_id(&name);
if (!id) return Qfalse;
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) {
goto wrong_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 (!rb_is_const_name(part)) {
name = part;
goto wrong_name;
}
else {
return Qfalse;
}
}
if (!rb_is_const_id(id)) {
name = ID2SYM(id);
goto wrong_name;
}
#if 0
mod = rb_const_search(mod, id, beglen > 0 || !RTEST(recur), RTEST(recur), FALSE);
if (UNDEF_P(mod)) return Qfalse;
#else
if (!RTEST(recur)) {
if (!rb_const_defined_at(mod, id))
return Qfalse;
if (p == pend) return Qtrue;
mod = rb_const_get_at(mod, id);
}
else if (beglen == 0) {
if (!rb_const_defined(mod, id))
return Qfalse;
if (p == pend) return Qtrue;
mod = rb_const_get(mod, id);
}
else {
if (!rb_const_defined_from(mod, id))
return Qfalse;
if (p == pend) return Qtrue;
mod = rb_const_get_from(mod, id);
}
#endif
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;
wrong_name:
rb_name_err_raise(wrong_constant_name, mod, name);
UNREACHABLE_RETURN(Qundef);
}
Checks for a constant with the given name in mod. If inherit is set, the lookup will also search the ancestors (and Object if mod is a Module).
The value of the constant is returned if a definition is found, otherwise a NameError is raised.
Math.const_get(:PI) #=> 3.14159265358979
This method will recursively look up constant names if a namespaced class name is provided. For example:
module Foo; class Bar; end end Object.const_get 'Foo::Bar'
The inherit flag is respected on each lookup. For example:
module Foo class Bar VAL = 10 end class Baz < Bar; end end Object.const_get 'Foo::Baz::VAL' # => 10 Object.const_get 'Foo::Baz::VAL', false # => NameError
If the argument is not a valid constant name a NameError will be raised with a warning “wrong constant name”.
Object.const_get 'foobar' #=> NameError: wrong constant name foobar
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;
rb_check_arity(argc, 1, 2);
name = argv[0];
recur = (argc == 1) ? Qtrue : argv[1];
if (SYMBOL_P(name)) {
if (!rb_is_const_sym(name)) goto wrong_name;
id = rb_check_id(&name);
if (!id) return rb_const_missing(mod, name);
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) {
goto wrong_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 (!rb_is_const_name(part)) {
name = part;
goto wrong_name;
}
else if (!rb_method_basic_definition_p(CLASS_OF(mod), id_const_missing)) {
part = rb_str_intern(part);
mod = rb_const_missing(mod, part);
continue;
}
else {
rb_mod_const_missing(mod, part);
}
}
if (!rb_is_const_id(id)) {
name = ID2SYM(id);
goto wrong_name;
}
#if 0
mod = rb_const_get_0(mod, id, beglen > 0 || !RTEST(recur), RTEST(recur), FALSE);
#else
if (!RTEST(recur)) {
mod = rb_const_get_at(mod, id);
}
else if (beglen == 0) {
mod = rb_const_get(mod, id);
}
else {
mod = rb_const_get_from(mod, id);
}
#endif
}
return mod;
wrong_name:
rb_name_err_raise(wrong_constant_name, mod, name);
UNREACHABLE_RETURN(Qundef);
}
Invoked when a reference is made to an undefined constant in mod. It is passed a symbol for the undefined constant, and returns a value to be used for that constant. For example, consider:
def Foo.const_missing(name) name # return the constant name as Symbol end Foo::UNDEFINED_CONST #=> :UNDEFINED_CONST: symbol returned
As the example above shows, const_missing is not required to create the missing constant in mod, though that is often a side-effect. The caller gets its return value when triggered. If the constant is also defined, further lookups won’t hit const_missing and will return the value stored in the constant as usual. Otherwise, const_missing will be invoked again.
In the next example, when a reference is made to an undefined constant, const_missing attempts to load a file whose path is the lowercase version of the constant name (thus class Fred is assumed to be in file fred.rb). If defined as a side-effect of loading the file, the method returns the value stored in the constant. This implements an autoload feature similar to Kernel#autoload and Module#autoload, though it differs in important ways.
def Object.const_missing(name) @looked_for ||= {} str_name = name.to_s raise "Constant not found: #{name}" if @looked_for[str_name] @looked_for[str_name] = 1 file = str_name.downcase require file const_get(name, false) end
VALUE
rb_mod_const_missing(VALUE klass, VALUE name)
{
rb_execution_context_t *ec = GET_EC();
VALUE ref = ec->private_const_reference;
rb_vm_pop_cfunc_frame();
if (ref) {
ec->private_const_reference = 0;
rb_name_err_raise("private constant %2$s::%1$s referenced", ref, name);
}
uninitialized_constant(klass, name);
UNREACHABLE_RETURN(Qnil);
}
Sets the named constant to the given object, returning that object. Creates a new constant if no constant with the given name previously existed.
Math.const_set("HIGH_SCHOOL_PI", 22.0/7.0) #=> 3.14285714285714 Math::HIGH_SCHOOL_PI - Math::PI #=> 0.00126448926734968
If sym or str is not a valid constant name a NameError will be raised with a warning “wrong constant name”.
Object.const_set('foobar', 42) #=> NameError: wrong constant name foobar
static VALUE
rb_mod_const_set(VALUE mod, VALUE name, VALUE value)
{
ID id = id_for_var(mod, name, const);
if (!id) id = rb_intern_str(name);
rb_const_set(mod, id, value);
return value;
}
Returns the Ruby source filename and line number containing the definition of the constant specified. If the named constant is not found, nil is returned. If the constant is found, but its source location can not be extracted (constant is defined in C code), empty array is returned.
inherit specifies whether to lookup in mod.ancestors (true by default).
# test.rb: class A # line 1 C1 = 1 C2 = 2 end module M # line 6 C3 = 3 end class B < A # line 10 include M C4 = 4 end class A # continuation of A definition C2 = 8 # constant redefinition; warned yet allowed end p B.const_source_location('C4') # => ["test.rb", 12] p B.const_source_location('C3') # => ["test.rb", 7] p B.const_source_location('C1') # => ["test.rb", 2] p B.const_source_location('C3', false) # => nil -- don't lookup in ancestors p A.const_source_location('C2') # => ["test.rb", 16] -- actual (last) definition place p Object.const_source_location('B') # => ["test.rb", 10] -- top-level constant could be looked through Object p Object.const_source_location('A') # => ["test.rb", 1] -- class reopening is NOT considered new definition p B.const_source_location('A') # => ["test.rb", 1] -- because Object is in ancestors p M.const_source_location('A') # => ["test.rb", 1] -- Object is not ancestor, but additionally checked for modules p Object.const_source_location('A::C1') # => ["test.rb", 2] -- nesting is supported p Object.const_source_location('String') # => [] -- constant is defined in C code
static VALUE
rb_mod_const_source_location(int argc, VALUE *argv, VALUE mod)
{
VALUE name, recur, loc = Qnil;
rb_encoding *enc;
const char *pbeg, *p, *path, *pend;
ID id;
rb_check_arity(argc, 1, 2);
name = argv[0];
recur = (argc == 1) ? Qtrue : argv[1];
if (SYMBOL_P(name)) {
if (!rb_is_const_sym(name)) goto wrong_name;
id = rb_check_id(&name);
if (!id) return Qnil;
return RTEST(recur) ? rb_const_source_location(mod, id) : rb_const_source_location_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) {
goto wrong_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 (!rb_is_const_name(part)) {
name = part;
goto wrong_name;
}
else {
return Qnil;
}
}
if (!rb_is_const_id(id)) {
name = ID2SYM(id);
goto wrong_name;
}
if (p < pend) {
if (RTEST(recur)) {
mod = rb_const_get(mod, id);
}
else {
mod = rb_const_get_at(mod, id);
}
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));
}
}
else {
if (RTEST(recur)) {
loc = rb_const_source_location(mod, id);
}
else {
loc = rb_const_source_location_at(mod, id);
}
break;
}
recur = Qfalse;
}
return loc;
wrong_name:
rb_name_err_raise(wrong_constant_name, mod, name);
UNREACHABLE_RETURN(Qundef);
}
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.
The implementation makes no guarantees about the order in which the constants are yielded.
IO.constants.include?(:SYNC) #=> true IO.constants(false).include?(:SYNC) #=> false
Also see Module#const_defined?.
VALUE
rb_mod_constants(int argc, const VALUE *argv, VALUE mod)
{
bool inherit = true;
if (rb_check_arity(argc, 0, 1)) inherit = RTEST(argv[0]);
if (inherit) {
return rb_const_list(rb_mod_const_of(mod, 0));
}
else {
return rb_local_constants(mod);
}
}
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. If a block or the method parameter has parameters, they’re used as method parameters. This block is evaluated using instance_eval.
class A def fred puts "In Fred" end def create_method(name, &block) self.class.define_method(name, &block) end define_method(:wilma) { puts "Charge it!" } define_method(:flint) {|name| puts "I'm #{name}!"} end class B < A define_method(:barney, instance_method(:fred)) end a = B.new a.barney a.wilma a.flint('Dino') a.create_method(:betty) { p self } a.betty
produces:
In Fred Charge it! I'm Dino! #<B:0x401b39e8>
static VALUE
rb_mod_define_method(int argc, VALUE *argv, VALUE mod)
{
const rb_cref_t *cref = rb_vm_cref_in_context(mod, mod);
const rb_scope_visibility_t default_scope_visi = {METHOD_VISI_PUBLIC, FALSE};
const rb_scope_visibility_t *scope_visi = &default_scope_visi;
if (cref) {
scope_visi = CREF_SCOPE_VISI(cref);
}
return rb_mod_define_method_with_visibility(argc, argv, mod, scope_visi);
}
Makes a list of existing constants deprecated. Attempt to refer to them will produce a warning.
module HTTP NotFound = Exception.new NOT_FOUND = NotFound # previous version of the library used this name deprecate_constant :NOT_FOUND end HTTP::NOT_FOUND # warning: constant HTTP::NOT_FOUND is deprecated
VALUE
rb_mod_deprecate_constant(int argc, const VALUE *argv, VALUE obj)
{
set_const_visibility(obj, argc, argv, CONST_DEPRECATED, CONST_DEPRECATED);
return obj;
}
Prevents further modifications to mod.
This method returns self.
static VALUE
rb_mod_freeze(VALUE mod)
{
rb_class_name(mod);
return rb_obj_freeze(mod);
}
Invokes Module.append_features on each parameter in reverse order.
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");
if (BUILTIN_TYPE(module) == T_MODULE && FL_TEST(module, RMODULE_IS_REFINEMENT)) {
rb_raise(rb_eTypeError, "Refinement#include has been removed");
}
rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
for (i = 0; i < argc; i++) {
Check_Type(argv[i], T_MODULE);
if (FL_TEST(argv[i], RMODULE_IS_REFINEMENT)) {
rb_raise(rb_eTypeError, "Cannot include refinement");
}
}
while (argc--) {
rb_funcall(argv[argc], id_append_features, 1, module);
rb_funcall(argv[argc], id_included, 1, module);
}
return module;
}
Returns true if module is included or prepended 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
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 && !FL_TEST(p, RICLASS_IS_ORIGIN)) {
if (METACLASS_OF(p) == mod2) return Qtrue;
}
}
return Qfalse;
}
Returns the list of modules included or prepended in mod or one of mod’s ancestors.
module Sub end module Mixin prepend Sub end module Outer include Mixin end Mixin.included_modules #=> [Sub] Outer.included_modules #=> [Sub, Mixin]
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 && RCLASS_ORIGIN(p) == p && BUILTIN_TYPE(p) == T_ICLASS) {
VALUE m = METACLASS_OF(p);
if (RB_TYPE_P(m, T_MODULE))
rb_ary_push(ary, m);
}
}
return ary;
}
Returns 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 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!
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_unbound(mod, id, rb_cUnboundMethod, FALSE);
}
Returns an array containing the names of the public and protected instance methods in the receiver. For a module, these are the public and protected methods; for a class, they are the instance (not singleton) methods. If the optional parameter is false, the methods of any ancestors are not included.
module A def method1() end end class B include A def method2() end end class C < B def method3() end end A.instance_methods(false) #=> [:method1] B.instance_methods(false) #=> [:method2] B.instance_methods(true).include?(:method1) #=> true C.instance_methods(false) #=> [:method3] C.instance_methods.include?(:method2) #=> true
Note that method visibility changes in the current class, as well as aliases, are considered as methods of the current class by this method:
class C < B alias method4 method2 protected :method2 end C.instance_methods(false).sort #=> [:method2, :method3, :method4]
VALUE
rb_class_instance_methods(int argc, const VALUE *argv, VALUE mod)
{
return class_instance_method_list(argc, argv, mod, 0, ins_methods_i);
}
Returns true if the named method is defined by mod. If inherit is set, the lookup will also search mod’s ancestors. Public and protected methods are matched. String arguments are converted to symbols.
module A def method1() end def protected_method1() end protected :protected_method1 end class B def method2() end def private_method2() end private :private_method2 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? "method2", true #=> true C.method_defined? "method2", false #=> false C.method_defined? "method3" #=> true C.method_defined? "protected_method1" #=> true C.method_defined? "method4" #=> false C.method_defined? "private_method2" #=> false
static VALUE
rb_mod_method_defined(int argc, VALUE *argv, VALUE mod)
{
rb_method_visibility_t visi = check_definition_visibility(mod, argc, argv);
return RBOOL(visi == METHOD_VISI_PUBLIC || visi == METHOD_VISI_PROTECTED);
}
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
static VALUE
rb_mod_module_eval_internal(int argc, const VALUE *argv, VALUE mod)
{
return specific_eval(argc, argv, mod, FALSE, RB_PASS_CALLED_KEYWORDS);
}
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!
static VALUE
rb_mod_module_exec_internal(int argc, const VALUE *argv, VALUE mod)
{
return yield_under(mod, FALSE, argc, argv, RB_PASS_CALLED_KEYWORDS);
}
Returns the name of the module mod. Returns nil for anonymous modules.
VALUE
rb_mod_name(VALUE mod)
{
bool permanent;
return classname(mod, &permanent);
}
Invokes Module.prepend_features on each parameter in reverse order.
static VALUE
rb_mod_prepend(int argc, VALUE *argv, VALUE module)
{
int i;
ID id_prepend_features, id_prepended;
if (BUILTIN_TYPE(module) == T_MODULE && FL_TEST(module, RMODULE_IS_REFINEMENT)) {
rb_raise(rb_eTypeError, "Refinement#prepend has been removed");
}
CONST_ID(id_prepend_features, "prepend_features");
CONST_ID(id_prepended, "prepended");
rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
for (i = 0; i < argc; i++) {
Check_Type(argv[i], T_MODULE);
if (FL_TEST(argv[i], RMODULE_IS_REFINEMENT)) {
rb_raise(rb_eTypeError, "Cannot prepend refinement");
}
}
while (argc--) {
rb_funcall(argv[argc], id_prepend_features, 1, module);
rb_funcall(argv[argc], id_prepended, 1, module);
}
return module;
}
Makes existing class methods private. Often used to hide the default constructor new.
String arguments are converted to symbols. An Array of Symbols and/or Strings is also accepted.
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(int argc, VALUE *argv, VALUE obj)
{
set_method_visibility(rb_singleton_class(obj), argc, argv, METHOD_VISI_PRIVATE);
return obj;
}
Makes a list of existing constants private.
VALUE
rb_mod_private_constant(int argc, const VALUE *argv, VALUE obj)
{
set_const_visibility(obj, argc, argv, CONST_PRIVATE, CONST_VISIBILITY_MASK);
return obj;
}
Returns a list of the private instance methods defined in mod. If the optional parameter is false, the methods of any ancestors are not included.
module Mod def method1() end private :method1 def method2() end end Mod.instance_methods #=> [:method2] Mod.private_instance_methods #=> [:method1]
VALUE
rb_class_private_instance_methods(int argc, const VALUE *argv, VALUE mod)
{
return class_instance_method_list(argc, argv, mod, 0, ins_methods_priv_i);
}
Returns true if the named private method is defined by mod. If inherit is set, the lookup will also search mod’s 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.private_method_defined? "method2", true #=> true C.private_method_defined? "method2", false #=> false C.method_defined? "method2" #=> false
static VALUE
rb_mod_private_method_defined(int argc, VALUE *argv, VALUE mod)
{
return check_definition(mod, argc, argv, METHOD_VISI_PRIVATE);
}
Returns a list of the protected instance methods defined in mod. If the optional parameter is false, the methods of any ancestors are not included.
VALUE
rb_class_protected_instance_methods(int argc, const VALUE *argv, VALUE mod)
{
return class_instance_method_list(argc, argv, mod, 0, ins_methods_prot_i);
}
Returns true if the named protected method is defined mod. If inherit is set, the lookup will also search mod’s 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.protected_method_defined? "method2", true #=> true C.protected_method_defined? "method2", false #=> false C.method_defined? "method2" #=> true
static VALUE
rb_mod_protected_method_defined(int argc, VALUE *argv, VALUE mod)
{
return check_definition(mod, argc, argv, METHOD_VISI_PROTECTED);
}
Makes a list of existing class methods public.
String arguments are converted to symbols. An Array of Symbols and/or Strings is also accepted.
static VALUE
rb_mod_public_method(int argc, VALUE *argv, VALUE obj)
{
set_method_visibility(rb_singleton_class(obj), argc, argv, METHOD_VISI_PUBLIC);
return obj;
}
Makes a list of existing constants public.
VALUE
rb_mod_public_constant(int argc, const VALUE *argv, VALUE obj)
{
set_const_visibility(obj, argc, argv, CONST_PUBLIC, CONST_VISIBILITY_MASK);
return obj;
}
Similar to instance_method, searches public method only.
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_unbound(mod, id, rb_cUnboundMethod, TRUE);
}
Returns a list of the public instance methods defined in mod. If the optional parameter is false, the methods of any ancestors are not included.
VALUE
rb_class_public_instance_methods(int argc, const VALUE *argv, VALUE mod)
{
return class_instance_method_list(argc, argv, mod, 0, ins_methods_pub_i);
}
Returns true if the named public method is defined by mod. If inherit is set, the lookup will also search mod’s 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? "method1", true #=> true C.public_method_defined? "method1", false #=> true C.public_method_defined? "method2" #=> false C.method_defined? "method2" #=> true
static VALUE
rb_mod_public_method_defined(int argc, VALUE *argv, VALUE mod)
{
return check_definition(mod, argc, argv, METHOD_VISI_PUBLIC);
}
Returns an array of modules defined within the receiver.
module A refine Integer do end refine String do end end p A.refinements
produces:
[#<refinement:Integer@A>, #<refinement:String@A>]
static VALUE
mod_refinements(VALUE self)
{
ID id_refinements;
VALUE refinements;
CONST_ID(id_refinements, "__refinements__");
refinements = rb_attr_get(self, id_refinements);
if (NIL_P(refinements)) {
return rb_ary_new();
}
return rb_hash_values(refinements);
}
Removes the named class variable from the receiver, returning that variable’s value.
class Example @@var = 99 puts remove_class_variable(:@@var) p(defined? @@var) end
produces:
99 nil
VALUE
rb_mod_remove_cvar(VALUE mod, VALUE name)
{
const ID id = id_for_var_message(mod, name, class, "wrong class variable name %1$s");
st_data_t val;
if (!id) {
goto not_defined;
}
rb_check_frozen(mod);
val = rb_ivar_delete(mod, id, Qundef);
if (!UNDEF_P(val)) {
return (VALUE)val;
}
if (rb_cvar_defined(mod, id)) {
rb_name_err_raise("cannot remove %1$s for %2$s", mod, ID2SYM(id));
}
not_defined:
rb_name_err_raise("class variable %1$s not defined for %2$s",
mod, name);
UNREACHABLE_RETURN(Qundef);
}
Removes the method identified by symbol from the current class. For an example, see Module#undef_method. String arguments are converted to symbols.
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_err_raise("method '%1$s' not defined in %2$s",
mod, v);
}
remove_method(mod, id);
}
return mod;
}
Sets the temporary name of the module. This name is reflected in introspection of the module and the values that are related to it, such as instances, constants, and methods.
The name should be nil or a non-empty string that is not a valid constant path (to avoid confusing between permanent and temporary names).
The method can be useful to distinguish dynamically generated classes and modules without assigning them to constants.
If the module is given a permanent name by assigning it to a constant, the temporary name is discarded. A temporary name can’t be assigned to modules that have a permanent name.
If the given name is nil, the module becomes anonymous again.
Example:
m = Module.new # => #<Module:0x0000000102c68f38> m.name #=> nil m.set_temporary_name("fake_name") # => fake_name m.name #=> "fake_name" m.set_temporary_name(nil) # => #<Module:0x0000000102c68f38> m.name #=> nil c = Class.new c.set_temporary_name("MyClass(with description)") c.new # => #<MyClass(with description):0x0....> c::M = m c::M.name #=> "MyClass(with description)::M" # Assigning to a constant replaces the name with a permanent one C = c C.name #=> "C" C::M.name #=> "C::M" c.new # => #<C:0x0....>
VALUE
rb_mod_set_temporary_name(VALUE mod, VALUE name)
{
// We don't allow setting the name if the classpath is already permanent:
if (RCLASS_EXT(mod)->permanent_classpath) {
rb_raise(rb_eRuntimeError, "can't change permanent name");
}
if (NIL_P(name)) {
// Set the temporary classpath to NULL (anonymous):
RCLASS_SET_CLASSPATH(mod, 0, FALSE);
}
else {
// Ensure the name is a string:
StringValue(name);
if (RSTRING_LEN(name) == 0) {
rb_raise(rb_eArgError, "empty class/module name");
}
if (is_constant_path(name)) {
rb_raise(rb_eArgError, "the temporary name must not be a constant path to avoid confusion");
}
// Set the temporary classpath to the given name:
RCLASS_SET_CLASSPATH(mod, name, FALSE);
}
return mod;
}
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
static VALUE
rb_mod_singleton_p(VALUE klass)
{
return RBOOL(RCLASS_SINGLETON_P(klass));
}
Returns 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.
VALUE
rb_mod_to_s(VALUE klass)
{
ID id_defined_at;
VALUE refined_class, defined_at;
if (RCLASS_SINGLETON_P(klass)) {
VALUE s = rb_usascii_str_new2("#<Class:");
VALUE v = RCLASS_ATTACHED_OBJECT(klass);
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_class_name(klass);
}
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)
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;
}
Returns a list of the undefined instance methods defined in mod. The undefined methods of any ancestors are not included.
VALUE
rb_class_undefined_instance_methods(VALUE mod)
{
VALUE include_super = Qfalse;
return class_instance_method_list(1, &include_super, mod, 0, ins_methods_undef_i);
}
Private Instance Methods
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.
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;
}
Invoked as a callback whenever a constant is assigned on the receiver
module Chatty def self.const_added(const_name) super puts "Added #{const_name.inspect}" end FOO = 1 end
produces:
Added :FOO
#define rb_obj_mod_const_added rb_obj_dummy1
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
static VALUE
rb_mod_extend_object(VALUE mod, VALUE obj)
{
rb_extend_object(obj, mod);
return obj;
}
The equivalent of included, but for extended modules.
module A def self.extended(mod) puts "#{self} extended in #{mod}" end end module Enumerable extend A end # => prints "A extended in Enumerable"
#define rb_obj_mod_extended rb_obj_dummy1
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 # => prints "A included in Enumerable"
#define rb_obj_mod_included rb_obj_dummy1
Invoked as a callback whenever an instance method is added to the receiver.
module Chatty def self.method_added(method_name) puts "Adding #{method_name.inspect}" end def self.some_class_method() end def some_instance_method() end end
produces:
Adding :some_instance_method
#define rb_obj_mod_method_added rb_obj_dummy1
Invoked as a callback whenever an instance method is removed from the receiver.
module Chatty def self.method_removed(method_name) puts "Removing #{method_name.inspect}" end def self.some_class_method() end def some_instance_method() end class << self remove_method :some_class_method end remove_method :some_instance_method end
produces:
Removing :some_instance_method
#define rb_obj_mod_method_removed rb_obj_dummy1
Invoked as a callback whenever an instance method is undefined from the receiver.
module Chatty def self.method_undefined(method_name) puts "Undefining #{method_name.inspect}" end def self.some_class_method() end def some_instance_method() end class << self undef_method :some_class_method end undef_method :some_instance_method end
produces:
Undefining :some_instance_method
#define rb_obj_mod_method_undefined rb_obj_dummy1
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. If a single argument is passed, it is returned. If no argument is passed, nil is returned. If multiple arguments are passed, the arguments are returned as an array.
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"
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) {
rb_scope_module_func_set();
return Qnil;
}
set_method_visibility(module, argc, argv, METHOD_VISI_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, METHOD_VISI_UNDEF);
}
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, METHOD_VISI_PUBLIC);
}
if (argc == 1) {
return argv[0];
}
return rb_ary_new_from_values(argc, argv);
}
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.
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;
}
The equivalent of included, but for prepended modules.
module A def self.prepended(mod) puts "#{self} prepended to #{mod}" end end module Enumerable prepend A end # => prints "A prepended to Enumerable"
#define rb_obj_mod_prepended rb_obj_dummy1
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. An Array of Symbols and/or Strings is also accepted. If a single argument is passed, it is returned. If no argument is passed, nil is returned. If multiple arguments are passed, the arguments are returned as an array.
module Mod def a() end def b() end private def c() end private :a end Mod.private_instance_methods #=> [:a, :c]
Note that to show a private method on RDoc, use :doc:.
static VALUE
rb_mod_private(int argc, VALUE *argv, VALUE module)
{
return set_visibility(argc, argv, module, METHOD_VISI_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. An Array of Symbols and/or Strings is also accepted. If a single argument is passed, it is returned. If no argument is passed, nil is returned. If multiple arguments are passed, the arguments are returned as an array.
If a method has protected visibility, it is callable only where self of the context is the same as the method. (method definition or instance_eval). This behavior is different from Java’s protected method. Usually private should be used.
Note that a protected method is slow because it can’t use inline cache.
To show a private method on RDoc, use :doc: instead of this.
static VALUE
rb_mod_protected(int argc, VALUE *argv, VALUE module)
{
return set_visibility(argc, argv, module, METHOD_VISI_PROTECTED);
}
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. An Array of Symbols and/or Strings is also accepted. If a single argument is passed, it is returned. If no argument is passed, nil is returned. If multiple arguments are passed, the arguments are returned as an array.
static VALUE
rb_mod_public(int argc, VALUE *argv, VALUE module)
{
return set_visibility(argc, argv, module, METHOD_VISI_PUBLIC);
}
Refine mod in the receiver.
Returns a module, where refined methods are defined.
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();
VALUE block_handler = rb_vm_frame_block_handler(th->ec->cfp);
if (block_handler == VM_BLOCK_HANDLER_NONE) {
rb_raise(rb_eArgError, "no block given");
}
if (vm_block_handler_type(block_handler) != block_handler_type_iseq) {
rb_raise(rb_eArgError, "can't pass a Proc as a block to Module#refine");
}
ensure_class_or_module(klass);
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)) {
VALUE superclass = refinement_superclass(klass);
refinement = rb_refinement_new();
RCLASS_SET_SUPER(refinement, superclass);
RUBY_ASSERT(BUILTIN_TYPE(refinement) == T_MODULE);
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;
}
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.
VALUE
rb_mod_remove_const(VALUE mod, VALUE name)
{
const ID id = id_for_var(mod, name, a, constant);
if (!id) {
undefined_constant(mod, name);
}
return rb_const_remove(mod, id);
}
For the given method names, marks the method as passing keywords through a normal argument splat. This should only be called on methods that accept an argument splat (*args) but not explicit keywords or a keyword splat. It marks the method such that if the method is called with keyword arguments, the final hash argument is marked with a special flag such that if it is the final element of a normal argument splat to another method call, and that method call does not include explicit keywords or a keyword splat, the final element is interpreted as keywords. In other words, keywords will be passed through the method to other methods.
This should only be used for methods that delegate keywords to another method, and only for backwards compatibility with Ruby versions before 3.0. See www.ruby-lang.org/en/news/2019/12/12/separation-of-positional-and-keyword-arguments-in-ruby-3-0/ for details on why ruby2_keywords exists and when and how to use it.
This method will probably be removed at some point, as it exists only for backwards compatibility. As it does not exist in Ruby versions before 2.7, check that the module responds to this method before calling it:
module Mod def foo(meth, *args, &block) send(:"do_#{meth}", *args, &block) end ruby2_keywords(:foo) if respond_to?(:ruby2_keywords, true) end
However, be aware that if the ruby2_keywords method is removed, the behavior of the foo method using the above approach will change so that the method does not pass through keywords.
static VALUE
rb_mod_ruby2_keywords(int argc, VALUE *argv, VALUE module)
{
int i;
VALUE origin_class = RCLASS_ORIGIN(module);
rb_check_arity(argc, 1, UNLIMITED_ARGUMENTS);
rb_check_frozen(module);
for (i = 0; i < argc; i++) {
VALUE v = argv[i];
ID name = rb_check_id(&v);
rb_method_entry_t *me;
VALUE defined_class;
if (!name) {
rb_print_undef_str(module, v);
}
me = search_method(origin_class, name, &defined_class);
if (!me && RB_TYPE_P(module, T_MODULE)) {
me = search_method(rb_cObject, name, &defined_class);
}
if (UNDEFINED_METHOD_ENTRY_P(me) ||
UNDEFINED_REFINED_METHOD_P(me->def)) {
rb_print_undef(module, name, METHOD_VISI_UNDEF);
}
if (module == defined_class || origin_class == defined_class) {
switch (me->def->type) {
case VM_METHOD_TYPE_ISEQ:
if (ISEQ_BODY(me->def->body.iseq.iseqptr)->param.flags.has_rest &&
!ISEQ_BODY(me->def->body.iseq.iseqptr)->param.flags.has_kw &&
!ISEQ_BODY(me->def->body.iseq.iseqptr)->param.flags.has_kwrest) {
ISEQ_BODY(me->def->body.iseq.iseqptr)->param.flags.ruby2_keywords = 1;
rb_clear_method_cache(module, name);
}
else {
rb_warn("Skipping set of ruby2_keywords flag for %s (method accepts keywords or method does not accept argument splat)", rb_id2name(name));
}
break;
case VM_METHOD_TYPE_BMETHOD: {
VALUE procval = me->def->body.bmethod.proc;
if (vm_block_handler_type(procval) == block_handler_type_proc) {
procval = vm_proc_to_block_handler(VM_BH_TO_PROC(procval));
}
if (vm_block_handler_type(procval) == block_handler_type_iseq) {
const struct rb_captured_block *captured = VM_BH_TO_ISEQ_BLOCK(procval);
const rb_iseq_t *iseq = rb_iseq_check(captured->code.iseq);
if (ISEQ_BODY(iseq)->param.flags.has_rest &&
!ISEQ_BODY(iseq)->param.flags.has_kw &&
!ISEQ_BODY(iseq)->param.flags.has_kwrest) {
ISEQ_BODY(iseq)->param.flags.ruby2_keywords = 1;
rb_clear_method_cache(module, name);
}
else {
rb_warn("Skipping set of ruby2_keywords flag for %s (method accepts keywords or method does not accept argument splat)", rb_id2name(name));
}
break;
}
}
/* fallthrough */
default:
rb_warn("Skipping set of ruby2_keywords flag for %s (method not defined in Ruby)", rb_id2name(name));
break;
}
}
else {
rb_warn("Skipping set of ruby2_keywords flag for %s (can only set in method defining module)", rb_id2name(name));
}
}
return Qnil;
}
Import class refinements from module into the current class or module definition.
static VALUE
mod_using(VALUE self, VALUE module)
{
rb_control_frame_t *prev_cfp = previous_frame(GET_EC());
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");
}
if (rb_block_given_p()) {
ignored_block(module, "Module#");
}
rb_using_module(rb_vm_cref_replace_with_duplicated_cref(), module);
return self;
}