1Glib::Type(3) User Contributed Perl Documentation Glib::Type(3)
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6 Glib::Type - Utilities for dealing with the GLib Type system
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9 This package defines several utilities for dealing with the GLib type
10 system from Perl. Because of some fundamental differences in how the
11 GLib and Perl type systems work, a fair amount of the binding magic
12 leaks out, and you can find most of that in the "Glib::Type::register*"
13 functions, which register new types with the GLib type system.
14 Most of the rest of the functions provide introspection functionality,
16 such as listing properties and values and other cool stuff that is used
17 mainly by Glib's reference documentation generator (see Glib::GenPod).
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20 list = Glib::Type->list_ancestors ($package)
21 • $package (string)
22 List the ancestry of package, as seen by the GLib type system. The
24 important difference is that GLib's type system implements only single
25 inheritance, whereas Perl's @ISA allows multiple inheritance.
26 This returns the package names of the ancestral types in reverse order,
28 with the root of the tree at the end of the list.
29 See also list_interfaces ().
31 list = Glib::Type->list_interfaces ($package)
33 • $package (string)
34 List the GInterfaces implemented by the type associated with package.
36 The interfaces are returned as package names.
37 list = Glib::Type->list_signals ($package)
39 • $package (string)
40 List the signals associated with package. This lists only the signals
42 for package, not any of its parents. The signals are returned as a
43 list of anonymous hashes which mirror the GSignalQuery structure
44 defined in the C API reference.
45 - signal_id
47 Numeric id of a signal. It's rare that you'll need this in
48 Gtk2-Perl.
49 - signal_name
51 Name of the signal, such as what you'd pass to "signal_connect".
52 - itype
54 The instance type for which this signal is defined.
55 - signal_flags
57 GSignalFlags describing this signal.
58 - return_type
60 The return type expected from handlers for this signal. If undef
61 or not present, then no return is expected. The type name is
62 mapped to the corresponding Perl package name if it is known,
63 otherwise you get the raw C name straight from GLib.
64 - param_types
66 The types of the parameters passed to any callbacks connected to
67 the emission of this signal. The list does not include the
68 instance, which is always first, and the user data from
69 "signal_connect", which is always last (unless the signal was
70 connected with "swap", which swaps the instance and the data, but
71 you get the point).
72 list = Glib::Type->list_values ($package)
74 • $package (string)
75 List the legal values for the GEnum or GFlags type $package. If
77 $package is not a package name registered with the bindings, this name
78 is passed on to g_type_from_name() to see if it's a registered flags or
79 enum type that just hasn't been registered with the bindings by
80 "gperl_register_fundamental()" (see Glib::xsapi). If $package is not
81 the name of an enum or flags type, this function will croak.
82 Returns the values as a list of hashes, one hash for each value,
84 containing the value, name and nickname, eg. for Glib::SignalFlags
85 { value => 8,
87 name => 'G_SIGNAL_NO_RECURSE',
88 nick => 'no-recurse'
89 }
90 string = Glib::Type->package_from_cname ($cname)
92 • $cname (string)
93 Convert a C type name to the corresponding Perl package name. If no
95 package is registered to that type, returns $cname.
96 Glib::Type->register ($parent_class, $new_class, ...)
98 • $parent_class (package) type from which to derive
99 • $new_class (package) name of new type
101 • ... (list) arguments for creation
103 Register a new type with the GLib type system.
105 This is a traffic-cop function. If $parent_type derives from
107 Glib::Object, this passes the arguments through to "register_object".
108 If $parent_type is Glib::Flags or Glib::Enum, this strips $parent_type
109 and passes the remaining args on to "register_enum" or
110 "register_flags". See those functions' documentation for more
111 information.
112 Glib::Type->register_enum ($name, ...)
114 • $name (string) package name for new enum type
115 • ... (list) new enum's values; see description.
117 Register and initialize a new Glib::Enum type with the provided
119 "values". This creates a type properly registered GLib so that it can
120 be used for property and signal parameter or return types created with
121 "Glib::Type->register" or "Glib::Object::Subclass".
122 The list of values is used to create the "nicknames" that are used in
124 general Perl code; the actual numeric values used at the C level are
125 automatically assigned, starting with 1. If you need to specify a
126 particular numeric value for a nick, use an array reference containing
127 the nickname and the numeric value, instead. You may mix and match the
128 two styles.
129 Glib::Type->register_enum ('MyFoo::Bar',
131 'value-one', # assigned 1
132 'value-two', # assigned 2
133 ['value-three' => 15 ], # explicit 15
134 ['value-four' => 35 ], # explicit 35
135 'value-five', # assigned 5
136 );
137 If you use the array-ref form, beware: the code performs no validation
139 for unique values.
140 Glib::Type->register_flags ($name, ...)
142 • $name (string) package name of new flags type
143 • ... (list) flag values, see discussion.
145 Register and initialize a new Glib::Flags type with the provided
147 "values". This creates a type properly registered GLib so that it can
148 be used for property and signal parameter or return types created with
149 "Glib::Type->register" or "Glib::Object::Subclass".
150 The list of values is used to create the "nicknames" that are used in
152 general Perl code; the actual numeric values used at the C level are
153 automatically assigned, of the form 1<<i, starting with i = 0. If you
154 need to specify a particular numeric value for a nick, use an array
155 reference containing the nickname and the numeric value, instead. You
156 may mix and match the two styles.
157 Glib::Type->register_flags ('MyFoo::Baz',
159 'value-one', # assigned 1<<0
160 'value-two', # assigned 1<<1
161 ['value-three' => 1<<10 ], # explicit 1<<10
162 ['value-four' => 0x0f ], # explicit 0x0f
163 'value-five', # assigned 1<<4
164 );
165 If you use the array-ref form, beware: the code performs no validation
167 for unique values.
168 Glib::Type->register_object ($parent_package, $new_package, ...)
170 • $parent_package (string) name of the parent package, which must be
171 a derivative of Glib::Object.
172 • $new_package (string) usually __PACKAGE__.
174 • ... (list) key/value pairs controlling how the class is created.
176 Register new_package as an officially GLib-sanctioned derivative of the
178 (GObject derivative) parent_package. This automatically sets up an
179 @ISA entry for you, and creates a new GObjectClass under the hood.
180 The ... parameters are key/value pairs, currently supporting:
182 signals => HASHREF
184 The "signals" key contains a hash, keyed by signal names, which
185 describes how to set up the signals for new_package.
186 If the value is a code reference, the named signal must exist
188 somewhere in parent_package or its ancestry; the code reference
189 will be used to override the class closure for that signal. This
190 is the officially sanctioned way to override virtual methods on
191 Glib::Objects. The value may be a string rather than a code
192 reference, in which case the sub with that name in new_package will
193 be used. (The function should not be inherited.)
194 If the value is a hash reference, the key will be the name of a new
196 signal created with the properties defined in the hash. All of the
197 properties are optional, with defaults provided:
198 class_closure => subroutine or undef
200 Use this code reference (or sub name) as the class closure
201 (that is, the default handler for the signal). If not
202 specified, "do_signal_name", in the current package, is used.
203 return_type => package name or undef
205 Return type for the signal. If not specified, then the signal
206 has void return.
207 param_types => ARRAYREF
209 Reference to a list of parameter types (package names),
210 omitting the instance and user data. Callbacks connected to
211 this signal will receive the instance object as the first
212 argument, followed by arguments with the types listed here, and
213 finally by any user data that was supplied when the callback
214 was connected. Not specifying this key is equivalent to
215 supplying an empty list, which actually means instance and
216 maybe data.
217 flags => Glib::SignalFlags
219 Flags describing this signal's properties. See the GObject C
220 API reference' description of GSignalFlags for a complete
221 description.
222 accumulator => subroutine or undef
224 The signal accumulator is a special callback that can be used
225 to collect return values of the various callbacks that are
226 called during a signal emission. Generally, you can omit this
227 parameter; custom accumulators are used to do things like
228 stopping signal propagation by return value or creating a list
229 of returns, etc. See "SIGNALS" in Glib::Object::Subclass for
230 details.
231 properties => ARRAYREF
233 Array of Glib::ParamSpec objects, each describing an object
234 property to add to the new type. These properties are available
235 for use by all code that can access the object, regardless of
236 implementation language. See Glib::ParamSpec. This list may be
237 empty; if it is not, the functions "GET_PROPERTY" and
238 "SET_PROPERTY" in $new_package will be called to get and set the
239 values. Note that an object property is just a mechanism for
240 getting and setting a value -- it implies no storage. As a
241 convenience, however, Glib::Object provides fallbacks for
242 GET_PROPERTY and SET_PROPERTY which use the property nicknames as
243 hash keys in the object variable for storage.
244 Additionally, you may specify ParamSpecs as a describing hash
246 instead of as an object; this form allows you to supply explicit
247 getter and setter methods which override GET_PROPERY and
248 SET_PROPERTY. The getter and setter are both optional in the hash
249 form. For example:
250 Glib::Type->register_object ('Glib::Object', 'Foo',
252 properties => [
253 # specified normally
254 Glib::ParamSpec->string (...),
255 # specified explicitly
256 {
257 pspec => Glib::ParamSpec->int (...),
258 set => sub {
259 my ($object, $newval) = @_;
260 ...
261 },
262 get => sub {
263 my ($object) = @_;
264 ...
265 return $val;
266 },
267 },
268 ]
269 );
270 You can mix the two declaration styles as you like. If you have
272 individual "get_foo" / "set_foo" methods with the operative code
273 for a property then the "get"/"set" form is a handy way to go
274 straight to that.
275 interfaces => ARRAYREF
277 Array of interface package names that the new object implements.
278 Interfaces are the GObject way of doing multiple inheritance, thus,
279 in Perl, the package names will be prepended to @ISA and certain
280 inheritable and overrideable ALLCAPS methods will automatically be
281 called whenever needed. Which methods exactly depends on the
282 interface -- Gtk2::CellEditable for example uses START_EDITING,
283 EDITING_DONE, and REMOVE_WIDGET.
284
286 Glib
287
289 Copyright (C) 2003-2011 by the gtk2-perl team.
290 This software is licensed under the LGPL. See Glib for a full notice.
292perl v5.34.0 2022-01-21 Glib::Type(3)