3 ;;; Class construction protocol
5 ;;; (c) 2009 Straylight/Edgeware
8 ;;;----- Licensing notice ---------------------------------------------------
10 ;;; This file is part of the Sensible Object Design, an object system for C.
12 ;;; SOD is free software; you can redistribute it and/or modify
13 ;;; it under the terms of the GNU General Public License as published by
14 ;;; the Free Software Foundation; either version 2 of the License, or
15 ;;; (at your option) any later version.
17 ;;; SOD is distributed in the hope that it will be useful,
18 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
19 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 ;;; GNU General Public License for more details.
22 ;;; You should have received a copy of the GNU General Public License
23 ;;; along with SOD; if not, write to the Free Software Foundation,
24 ;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
28 ;;;--------------------------------------------------------------------------
31 (export 'make-sod-class)
32 (defun make-sod-class (name superclasses pset &optional location)
33 "Construct and return a new SOD class with the given NAME and SUPERCLASSES.
35 This is the main constructor function for classes. The protocol works as
36 follows. The `:lisp-metaclass' property in PSET is checked: if it exists,
37 it must be a symbol naming a (CLOS) class, which is used in place of
38 `sod-class'. All of the arguments are then passed to `make-instance';
39 further behaviour is left to the standard CLOS instance construction
40 protocol; for example, `sod-class' defines an `:after'-method on
43 Minimal sanity checking is done during class construction; most of it is
44 left for `finalize-sod-class' to do (via `check-sod-class')."
46 (with-default-error-location (location)
47 (let* ((pset (property-set pset))
48 (best-class (or (get-property pset :lisp-metaclass :symbol nil)
49 (select-minimal-class-property
50 superclasses #'class-of #'subtypep 'sod-class
52 :present (lambda (class)
56 (class (make-instance best-class
58 :superclasses superclasses
59 :location (file-location location)
63 ;;;--------------------------------------------------------------------------
64 ;;; Slots and slot initializers.
66 (export 'make-sod-slot)
67 (defgeneric make-sod-slot (class name type pset &optional location)
69 "Construct, add, and attach a new slot with given NAME and TYPE, to CLASS.
71 This is the main constructor function for slots. This is a generic
72 function primarily so that the CLASS can intervene in the construction
73 process. The default method uses the `:slot-class' property (defaulting
74 to `sod-slot') to choose a (CLOS) class to instantiate. The slot is then
75 constructed by `make-instance' passing the arguments as initargs; further
76 behaviour is left to the standard CLOS instance construction protocol; for
77 example, `sod-slot' defines an `:after'-method on `shared-initialize'."))
79 (export 'make-sod-instance-initializer)
80 (defgeneric make-sod-instance-initializer
81 (class nick name value pset &optional location)
83 "Construct and attach an instance slot initializer, to CLASS.
85 This is the main constructor function for instance initializers. This is
86 a generic function primarily so that the CLASS can intervene in the
87 construction process. The default method looks up the slot using
88 `find-instance-slot-by-name', calls `make-sod-initializer-using-slot' to
89 actually make the initializer object, and adds it to the appropriate list
92 (export 'make-sod-class-initializer)
93 (defgeneric make-sod-class-initializer
94 (class nick name value pset &optional location)
96 "Construct and attach a class slot initializer, to CLASS.
98 This is the main constructor function for class initializers. This is a
99 generic function primarily so that the CLASS can intervene in the
100 construction process. The default method looks up the slot using
101 `find-class-slot-by-name', calls `make-sod-initializer-using-slot' to
102 actually make the initializer object, and adds it to the appropriate list
105 (export 'make-sod-initializer-using-slot)
106 (defgeneric make-sod-initializer-using-slot
107 (class slot init-class value pset location)
109 "Common construction protocol for slot initializers.
111 This generic function does the common work for constructing instance and
112 class initializers. It can usefully be specialized according to both the
113 class and slot types. The default method uses the `:initializer-class'
114 property (defaulting to INIT-CLASS) to choose a (CLOS) class to
115 instantiate. The slot is then constructed by `make-instance' passing the
116 arguments as initargs; further behaviour is left to the standard CLOS
117 instance construction protocol; for example, `sod-initializer' defines an
118 `:after'-method on `shared-initialize'.
120 Diagnosing unused properties is left for the caller (usually
121 `make-sod-instance-initializer' or `make-sod-class-initializer') to do.
122 The caller is also expected to have set `with-default-error-location' if
125 You are not expected to call this generic function directly; it's more
126 useful as a place to hang methods for custom initializer classes."))
128 (export 'make-sod-user-initarg)
129 (defgeneric make-sod-user-initarg
130 (class name type pset &optional default location)
132 "Attach a user-defined initialization keyword argument to the CLASS.
134 The new argument has the given NAME and TYPE, and maybe a DEFAULT value.
135 Currently, initialization arguments are just dumb objects held in a
138 (export 'make-sod-slot-initarg)
139 (defgeneric make-sod-slot-initarg
140 (class name nick slot-name pset &optional location)
142 "Attach an initialization keyword argument to a slot by name.
144 The default method uses `find-instance-slot-by-name' to find the slot, and
145 `make-slot-initarg-using-slot' to actually make and attach the initarg."))
147 (export 'make-sod-slot-initarg-using-slot)
148 (defgeneric make-sod-slot-initarg-using-slot
149 (class name slot pset &optional location)
151 "Attach an initialization keyword argument to a SLOT.
153 The argument's type is taken from the slot type. Slot initargs can't have
154 defaults: the slot's most-specific initializer is used instead.
156 You are not expected to call this generic function directly; it's more
157 useful as a place to hang methods for custom classes."))
159 (export 'sod-initarg-argument)
160 (defgeneric sod-initarg-argument (initarg)
161 (:documentation "Returns an `argument' object for the initarg."))
163 (export 'make-sod-class-initfrag)
164 (defgeneric make-sod-class-initfrag (class frag pset &optional location)
166 "Attach an initialization fragment FRAG to the CLASS.
168 Currently, initialization fragments are just dumb objects held in a
171 (export 'make-sod-class-tearfrag)
172 (defgeneric make-sod-class-tearfrag (class frag pset &optional location)
174 "Attach a teardown fragment FRAG to the CLASS.
176 Currently, teardown fragments are just dumb objects held in a
179 ;;;--------------------------------------------------------------------------
180 ;;; Messages and methods.
182 (export 'make-sod-message)
183 (defgeneric make-sod-message (class name type pset &optional location)
185 "Construct and attach a new message with given NAME and TYPE, to CLASS.
187 This is the main constructor function for messages. This is a generic
188 function primarily so that the CLASS can intervene in the construction
189 process. The default method uses the `:message-class' property to choose
190 a (CLOS) class to instantiate; if no such property is provided but a
191 `combination' property is present, then `aggregating-message' is chosen;
192 otherwise `standard-message' is used. The message is then constructed by
193 `make-instance' passing the arguments as initargs; further behaviour is
194 left to the standard CLOS instance construction protocol; for example,
195 `sod-message' defines an `:after'-method on `shared-initialize'."))
197 (export 'make-sod-method)
198 (defgeneric make-sod-method
199 (class nick name type body pset &optional location)
201 "Construct and attach a new method to CLASS.
203 This is the main constructor function for methods. This is a generic
204 function primarily so that the CLASS can intervene in the message lookup
205 process, though this is actually a fairly unlikely occurrence.
207 The default method looks up the message using `find-message-by-name',
208 invokes `make-sod-method-using-message' to make the method object, and
209 then adds the method to the class's list of methods. This split allows
210 the message class to intervene in the class selection process, for
213 (export 'make-sod-method-using-message)
214 (defgeneric make-sod-method-using-message
215 (message class type body pset location)
217 "Main construction subroutine for method construction.
219 This is a generic function so that it can be specialized according to both
220 a class and -- more particularly -- a message. The default method uses
221 the `:method-class' property (defaulting to the result of calling
222 `sod-message-method-class') to choose a (CLOS) class to instantiate. The
223 method is then constructed by `make-instance' passing the arguments as
224 initargs; further behaviour is left to the standard CLOS instance
225 construction protocol; for example, `sod-method' defines an
226 `:after'-method on `shared-initialize'.
228 Diagnosing unused properties is left for the caller (usually
229 `make-sod-method') to do. The caller is also expected to have set
230 `with-default-error-location' if appropriate.
232 You are not expected to call this generic function directly; it's more
233 useful as a place to hang methods for custom method classes."))
235 (export 'sod-message-method-class)
236 (defgeneric sod-message-method-class (message class pset)
238 "Return the preferred class for methods on MESSAGE.
240 The message can inspect the PSET to decide on a particular message. A
241 `:method-class' property will usually override this decision: it's then
242 the programmer's responsibility to ensure that the selected method class
245 (export 'check-message-type)
246 (defgeneric check-message-type (message type)
248 "Check that TYPE is a suitable type for MESSAGE. Signal errors if not.
250 This is separated out of `shared-initialize', where it's called, so that
251 it can be overridden conveniently by subclasses."))
253 (export 'check-method-type)
254 (defgeneric check-method-type (method message type)
256 "Check that TYPE is a suitable type for METHOD. Signal errors if not.
258 This is separated out of `shared-initialize', where it's called, so that
259 it can be overridden conveniently by subclasses."))
261 ;;;----- That's all, folks --------------------------------------------------