Class: UnboundMethod

Inherits:
Object show all
Defined in:
proc.c,
proc.c

Overview

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

Ruby supports two forms of objectified methods. Class
<code>Method</code> is used to represent methods that are associated
with a particular object: these method objects are bound to that
object. Bound method objects for an object can be created using
<code>Object#method</code>.

Ruby also supports unbound methods; methods objects that are not
associated with a particular object. These can be created either by
calling <code>Module#instance_method</code> or by calling
<code>unbind</code> on a bound method object. The result of both of
these is an <code>UnboundMethod</code> object.

Unbound methods can only be called after they are bound to an
object. That object must be be a kind_of? the method's original
class.

   class Square
     def area
       @side * @side
     end
     def initialize(side)
       @side = side
     end
   end

   area_un = Square.instance_method(:area)

   s = Square.new(12)
   area = area_un.bind(s)
   area.call   #=> 144

Unbound methods are a reference to the method at the time it was
objectified: subsequent changes to the underlying class will not
affect the unbound method.

   class Test
     def test
       :original
     end
   end
   um = Test.instance_method(:test)
   class Test
     def test
       :modified
     end
   end
   t = Test.new
   t.test            #=> :modified
   um.bind(t).call   #=> :original

Instance Method Summary collapse

Instance Method Details

#eql?(other_meth) ⇒ Boolean #==(other_meth) ⇒ Boolean

Two method objects are equal if they are bound to the same object and refer to the same method definition and their owners are the same class or module.

Overloads:

  • #eql?(other_meth) ⇒ Boolean

    Returns:

    • (Boolean)
  • #==(other_meth) ⇒ Boolean

    Returns:

    • (Boolean) 


1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
 
# File 'proc.c', line 1264

static VALUE
method_eq(VALUE method, VALUE other)
{
    struct METHOD *m1, *m2;

    if (!rb_obj_is_method(other))
	return Qfalse;
    if (CLASS_OF(method) != CLASS_OF(other))
	return Qfalse;

    Check_TypedStruct(method, &method_data_type);
    m1 = (struct METHOD *)DATA_PTR(method);
    m2 = (struct METHOD *)DATA_PTR(other);

    if (!rb_method_entry_eq(m1->me, m2->me) ||
	m1->rclass != m2->rclass ||
	m1->recv != m2->recv) {
	return Qfalse;
    }

    return Qtrue;
}

#arity ⇒ Fixnum

Returns an indication of the number of arguments accepted by a method. Returns a nonnegative integer for methods that take a fixed number of arguments. For Ruby methods that take a variable number of arguments, returns -n-1, where n is the number of required arguments. For methods written in C, returns -1 if the call takes a variable number of arguments.

class C
  def one;    end
  def two(a); end
  def three(*a);  end
  def four(a, b); end
  def five(a, b, *c);    end
  def six(a, b, *c, &d); end
end
c = C.new
c.method(:one).arity     #=> 0
c.method(:two).arity     #=> 1
c.method(:three).arity   #=> -1
c.method(:four).arity    #=> 2
c.method(:five).arity    #=> -3
c.method(:six).arity     #=> -3

"cat".method(:size).arity      #=> 0
"cat".method(:replace).arity   #=> 1
"cat".method(:squeeze).arity   #=> -1
"cat".method(:count).arity     #=> -1

Returns:



2061
2062
2063
2064
2065
2066
 
# File 'proc.c', line 2061

static VALUE
method_arity_m(VALUE method)
{
    int n = method_arity(method);
    return INT2FIX(n);
}

#bind(obj) ⇒ Object

Bind umeth to obj. If Klass was the class from which umeth was obtained, obj.kind_of?(Klass) must be true.

class A
  def test
    puts "In test, class = #{self.class}"
  end
end
class B < A
end
class C < B
end

um = B.instance_method(:test)
bm = um.bind(C.new)
bm.call
bm = um.bind(B.new)
bm.call
bm = um.bind(A.new)
bm.call

produces:

In test, class = C
In test, class = B
prog.rb:16:in `bind': bind argument must be an instance of B (TypeError)
	from prog.rb:16



1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
 
# File 'proc.c', line 1934

static VALUE
umethod_bind(VALUE method, VALUE recv)
{
    struct METHOD *data, *bound;
    VALUE methclass;

    TypedData_Get_Struct(method, struct METHOD, &method_data_type, data);

    methclass = data->rclass;
    if (!RB_TYPE_P(methclass, T_MODULE) &&
	methclass != CLASS_OF(recv) && !rb_obj_is_kind_of(recv, methclass)) {
	if (FL_TEST(methclass, FL_SINGLETON)) {
	    rb_raise(rb_eTypeError,
		     "singleton method called for a different object");
	}
	else {
	    rb_raise(rb_eTypeError, "bind argument must be an instance of % "PRIsVALUE,
		     rb_class_name(methclass));
	}
    }

    method = TypedData_Make_Struct(rb_cMethod, struct METHOD, &method_data_type, bound);
    *bound = *data;
    bound->me = ALLOC(rb_method_entry_t);
    *bound->me = *data->me;
    if (bound->me->def) bound->me->def->alias_count++;
    bound->recv = recv;
    bound->rclass = CLASS_OF(recv);
    data->ume = ALLOC(struct unlinked_method_entry_list_entry);

    return method;
}

#clone ⇒ Object

Returns a clone of this method.

class A
  def foo
    return "bar"
  end
end

m = A.new.method(:foo)
m.call # => "bar"
n = m.clone.call # => "bar"



1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
 
# File 'proc.c', line 1764

static VALUE
method_clone(VALUE self)
{
    VALUE clone;
    struct METHOD *orig, *data;

    TypedData_Get_Struct(self, struct METHOD, &method_data_type, orig);
    clone = TypedData_Make_Struct(CLASS_OF(self), struct METHOD, &method_data_type, data);
    CLONESETUP(clone, self);
    *data = *orig;
    data->me = ALLOC(rb_method_entry_t);
    *data->me = *orig->me;
    if (data->me->def) data->me->def->alias_count++;
    data->ume = ALLOC(struct unlinked_method_entry_list_entry);

    return clone;
}

#eql?(other_meth) ⇒ Boolean #==(other_meth) ⇒ Boolean

Two method objects are equal if they are bound to the same object and refer to the same method definition and their owners are the same class or module.

Overloads:

  • #eql?(other_meth) ⇒ Boolean

    Returns:

    • (Boolean)
  • #==(other_meth) ⇒ Boolean

    Returns:

    • (Boolean)

Returns:

  • (Boolean) 


1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
 
# File 'proc.c', line 1264

static VALUE
method_eq(VALUE method, VALUE other)
{
    struct METHOD *m1, *m2;

    if (!rb_obj_is_method(other))
	return Qfalse;
    if (CLASS_OF(method) != CLASS_OF(other))
	return Qfalse;

    Check_TypedStruct(method, &method_data_type);
    m1 = (struct METHOD *)DATA_PTR(method);
    m2 = (struct METHOD *)DATA_PTR(other);

    if (!rb_method_entry_eq(m1->me, m2->me) ||
	m1->rclass != m2->rclass ||
	m1->recv != m2->recv) {
	return Qfalse;
    }

    return Qtrue;
}

#hash ⇒ Integer

Returns a hash value corresponding to the method object.

Returns:



1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
 
# File 'proc.c', line 1294

static VALUE
method_hash(VALUE method)
{
    struct METHOD *m;
    st_index_t hash;

    TypedData_Get_Struct(method, struct METHOD, &method_data_type, m);
    hash = rb_hash_start((st_index_t)m->rclass);
    hash = rb_hash_uint(hash, (st_index_t)m->recv);
    hash = rb_hash_method_entry(hash, m->me);
    hash = rb_hash_end(hash);

    return INT2FIX(hash);
}

#to_s ⇒ String #inspect ⇒ String

Returns the name of the underlying method.

"cat".method(:count).inspect   #=> "#<Method: String#count>"

Overloads:



2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
 
# File 'proc.c', line 2216

static VALUE
method_inspect(VALUE method)
{
    struct METHOD *data;
    VALUE str;
    const char *s;
    const char *sharp = "#";
    VALUE mklass;

    TypedData_Get_Struct(method, struct METHOD, &method_data_type, data);
    str = rb_str_buf_new2("#<");
    s = rb_obj_classname(method);
    rb_str_buf_cat2(str, s);
    rb_str_buf_cat2(str, ": ");

    mklass = data->me->klass;
    if (FL_TEST(mklass, FL_SINGLETON)) {
	VALUE v = rb_ivar_get(mklass, attached);

	if (data->recv == Qundef) {
	    rb_str_buf_append(str, rb_inspect(mklass));
	}
	else if (data->recv == v) {
	    rb_str_buf_append(str, rb_inspect(v));
	    sharp = ".";
	}
	else {
	    rb_str_buf_append(str, rb_inspect(data->recv));
	    rb_str_buf_cat2(str, "(");
	    rb_str_buf_append(str, rb_inspect(v));
	    rb_str_buf_cat2(str, ")");
	    sharp = ".";
	}
    }
    else {
	rb_str_buf_append(str, rb_class_name(data->rclass));
	if (data->rclass != mklass) {
	    rb_str_buf_cat2(str, "(");
	    rb_str_buf_append(str, rb_class_name(mklass));
	    rb_str_buf_cat2(str, ")");
	}
    }
    rb_str_buf_cat2(str, sharp);
    rb_str_append(str, rb_id2str(data->id));
    if (data->id != data->me->def->original_id) {
	rb_str_catf(str, "(%"PRIsVALUE")",
		    rb_id2str(data->me->def->original_id));
    }
    if (data->me->def->type == VM_METHOD_TYPE_NOTIMPLEMENTED) {
        rb_str_buf_cat2(str, " (not-implemented)");
    }
    rb_str_buf_cat2(str, ">");

    return str;
}

#name ⇒ Object

Returns the name of the method.



1363
1364
1365
1366
1367
1368
1369
1370
 
# File 'proc.c', line 1363

static VALUE
method_name(VALUE obj)
{
    struct METHOD *data;

    TypedData_Get_Struct(obj, struct METHOD, &method_data_type, data);
    return ID2SYM(data->id);
}

#original_name ⇒ Object

Returns the original name of the method.



1379
1380
1381
1382
1383
1384
1385
1386
 
# File 'proc.c', line 1379

static VALUE
method_original_name(VALUE obj)
{
    struct METHOD *data;

    TypedData_Get_Struct(obj, struct METHOD, &method_data_type, data);
    return ID2SYM(data->me->def->original_id);
}

#owner ⇒ Object

Returns the class or module that defines the method.



1395
1396
1397
1398
1399
1400
1401
1402
 
# File 'proc.c', line 1395

static VALUE
method_owner(VALUE obj)
{
    struct METHOD *data;

    TypedData_Get_Struct(obj, struct METHOD, &method_data_type, data);
    return data->defined_class;
}

#parameters ⇒ Array

Returns the parameter information of this method.

Returns:



2196
2197
2198
2199
2200
2201
2202
2203
2204
 
# File 'proc.c', line 2196

static VALUE
rb_method_parameters(VALUE method)
{
    rb_iseq_t *iseq = rb_method_get_iseq(method);
    if (!iseq) {
	return unnamed_parameters(method_arity(method));
    }
    return rb_iseq_parameters(iseq, 0);
}

#source_location ⇒ Array, Fixnum

Returns the Ruby source filename and line number containing this method or nil if this method was not defined in Ruby (i.e. native)

Returns ].

Returns:



2182
2183
2184
2185
2186
2187
 
# File 'proc.c', line 2182

VALUE
rb_method_location(VALUE method)
{
    rb_method_definition_t *def = method_get_def(method);
    return method_def_location(def);
}

#to_s ⇒ String #inspect ⇒ String

Returns the name of the underlying method.

"cat".method(:count).inspect   #=> "#<Method: String#count>"

Overloads:



2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
 
# File 'proc.c', line 2216

static VALUE
method_inspect(VALUE method)
{
    struct METHOD *data;
    VALUE str;
    const char *s;
    const char *sharp = "#";
    VALUE mklass;

    TypedData_Get_Struct(method, struct METHOD, &method_data_type, data);
    str = rb_str_buf_new2("#<");
    s = rb_obj_classname(method);
    rb_str_buf_cat2(str, s);
    rb_str_buf_cat2(str, ": ");

    mklass = data->me->klass;
    if (FL_TEST(mklass, FL_SINGLETON)) {
	VALUE v = rb_ivar_get(mklass, attached);

	if (data->recv == Qundef) {
	    rb_str_buf_append(str, rb_inspect(mklass));
	}
	else if (data->recv == v) {
	    rb_str_buf_append(str, rb_inspect(v));
	    sharp = ".";
	}
	else {
	    rb_str_buf_append(str, rb_inspect(data->recv));
	    rb_str_buf_cat2(str, "(");
	    rb_str_buf_append(str, rb_inspect(v));
	    rb_str_buf_cat2(str, ")");
	    sharp = ".";
	}
    }
    else {
	rb_str_buf_append(str, rb_class_name(data->rclass));
	if (data->rclass != mklass) {
	    rb_str_buf_cat2(str, "(");
	    rb_str_buf_append(str, rb_class_name(mklass));
	    rb_str_buf_cat2(str, ")");
	}
    }
    rb_str_buf_cat2(str, sharp);
    rb_str_append(str, rb_id2str(data->id));
    if (data->id != data->me->def->original_id) {
	rb_str_catf(str, "(%"PRIsVALUE")",
		    rb_id2str(data->me->def->original_id));
    }
    if (data->me->def->type == VM_METHOD_TYPE_NOTIMPLEMENTED) {
        rb_str_buf_cat2(str, " (not-implemented)");
    }
    rb_str_buf_cat2(str, ">");

    return str;
}