3 ;;; Protocol for property sets
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 ;;;--------------------------------------------------------------------------
29 ;;; Property representation.
31 (export 'property-key)
32 (defun property-key (name)
33 "Convert NAME into a keyword.
35 If NAME isn't a symbol already, then flip its case (using
36 `frob-identifier'), and intern into the `keyword' package."
39 (string (intern (frob-identifier name) :keyword))))
41 (export '(property propertyp p-name p-value p-type p-key p-seenp))
43 (:predicate propertyp)
45 (:constructor %make-property
47 &key type location seenp
48 &aux (key (property-key name)) (%type type))))
49 "A simple structure for holding a property in a property set.
51 The main useful feature is the ability to tick off properties which have
52 been used, so that we can complain about unrecognized properties.
54 An explicit type tag is necessary because we need to be able to talk
55 distinctly about identifiers, strings and symbols, and we've only got two
56 obvious Lisp types to play with. Sad, but true."
58 (name nil :type (or string symbol) :read-only t)
59 (value nil :type t :read-only t)
60 (%type nil :type symbol :read-only t)
61 (location (file-location nil) :type file-location :read-only t)
62 (key nil :type symbol :read-only t)
63 (seenp nil :type boolean))
64 (define-access-wrapper p-type p-%type :read-only t)
66 (export 'decode-property)
67 (defgeneric decode-property (raw)
68 (:documentation "Decode a RAW value into a TYPE, VALUE pair.")
69 (:method ((raw symbol)) (values :symbol raw))
70 (:method ((raw integer)) (values :int raw))
71 (:method ((raw string)) (values :string raw))
72 (:method ((raw character)) (values :char raw))
73 (:method ((raw property)) (values (p-type raw) (p-value raw)))
74 (:method ((raw cons)) (values (car raw) (cdr raw)))
75 (:method ((raw function)) (values :func raw))
76 (:method ((raw c-type)) (values :type raw)))
78 (export 'make-property)
79 (defun make-property (name raw-value &key type location seenp)
80 (multiple-value-bind (type value)
82 (values type raw-value)
83 (decode-property raw-value))
84 (%make-property name value
86 :location (file-location location)
89 (defun string-to-symbol
90 (string &key (package *package*) (swap-case t) (swap-hyphen t))
91 "Convert STRING to a symbol in PACKAGE.
93 Parse off a `PACKAGE:' prefix from STRING if necessary, to identify the
94 package; PACKAGE is used if there isn't a prefix. A doubled colon allows
95 access to internal symbols, and will intern if necessary. Note that
96 escape characters are /not/ processed; don't put colons in package names
97 if you want to use them from SOD property sets.
99 The portions of the string are modified by `frob-identifier'; the
100 arguments SWAP-CASE and SWAP-HYPHEN are passed to `frob-identifier' to
101 control this process."
103 (let* ((length (length string))
104 (colon (position #\: string)))
105 (multiple-value-bind (start internalp)
106 (cond ((not colon) (values 0 t))
107 ((and (< (1+ colon) length)
108 (char= (char string (1+ colon)) #\:))
109 (values (+ colon 2) t))
111 (values (1+ colon) nil)))
113 (let* ((package-name (if (zerop colon) "KEYWORD"
114 (frob-identifier (subseq string 0 colon)
116 :swap-hyphen swap-hyphen)))
117 (found (find-package package-name)))
119 (error "Unknown package `~A'" package-name))
120 (setf package found)))
121 (let ((name (frob-identifier (subseq string start)
123 :swap-hyphen swap-hyphen)))
124 (multiple-value-bind (symbol status)
125 (funcall (if internalp #'intern #'find-symbol) name package)
126 (cond ((or internalp (eq status :external))
129 (error "Symbol `~A' not found in package `~A'"
130 name (package-name package)))
132 (error "Symbol `~A' not external in package `~A'"
133 name (package-name package)))))))))
135 (export 'coerce-property-value)
136 (defgeneric coerce-property-value (value type wanted)
138 "Convert VALUE, a property of type TYPE, to be of type WANTED.
140 It's sensible to add additional methods to this function, but there are
141 all the ones we need.")
143 ;; If TYPE matches WANTED, we'll assume that VALUE already has the right
144 ;; form. Otherwise, if nothing else matched, then I guess we'll have to
145 ;; say it didn't work.
146 (:method (value type wanted)
147 (if (eql type wanted) value
148 (error "Incorrect type: expected ~A but found ~A" wanted type)))
150 ;; If the caller asks for type T then give him the raw thing.
151 (:method (value type (wanted (eql t)))
152 (declare (ignore type))
155 ;;;--------------------------------------------------------------------------
156 ;;; Property set representation.
158 (export '(pset psetp))
159 (defstruct (pset (:predicate psetp)
160 (:constructor %make-pset)
164 Wrapped up in a structure so that we can define a print function."
165 (hash (make-hash-table) :type hash-table))
167 (export '(make-pset pset-get pset-store pset-map))
168 (declaim (inline make-pset pset-get pset-store pset-map))
171 "Constructor for property sets."
174 (defun pset-get (pset key)
175 "Look KEY up in PSET and return what we find.
177 If there's no property by that name, return nil."
178 (values (gethash key (%pset-hash pset))))
180 (defun pset-store (pset prop)
181 "Store property PROP in PSET.
183 Overwrite or replace any previous property with the same name. Mutates
185 (setf (gethash (p-key prop) (%pset-hash pset)) prop))
187 (defun pset-map (func pset)
188 "Call FUNC for each property in PSET."
189 (maphash (lambda (key value) (declare (ignore key)) (funcall func value))
192 (export 'with-pset-iterator)
193 (defmacro with-pset-iterator ((name pset) &body body)
194 "Evaluate BODY with NAME bound to a macro returning properties from PSET.
196 Evaluating (NAME) returns a property object or nil if all properties have
198 (with-gensyms (next win key value)
199 `(with-hash-table-iterator (,next (%pset-hash ,pset))
201 `(multiple-value-bind (,',win ,',key ,',value) (,',next)
202 (declare (ignore ,',key))
203 (and ,',win ,',value))))
206 ;;;--------------------------------------------------------------------------
207 ;;; `Cooked' property set operations.
209 (export 'store-property)
210 (defun store-property
211 (pset name value &key type location)
212 "Store a property in PSET."
214 (make-property name value :type type :location location)))
216 (export 'get-property)
217 (defun get-property (pset name type &optional default)
218 "Fetch a property from a property set.
220 If a property NAME is not found in PSET, or if a property is found, but
221 its type doesn't match TYPE, then return DEFAULT and nil; otherwise return
222 the value and its file location. In the latter case, mark the property as
225 The value returned depends on the TYPE argument provided. If you pass
226 `nil' then you get back the entire `property' object. If you pass `t',
227 then you get whatever was left in the property set, uninterpreted.
228 Otherwise the value is coerced to the right kind of thing (where possible)
231 The file location at which the property was defined is returned as a
234 If PSET is nil, then return DEFAULT and nil."
236 (let ((prop (and pset (pset-get pset (property-key name)))))
237 (with-default-error-location ((and prop (p-location prop)))
239 (values default nil))
241 (setf (p-seenp prop) t)
242 (values prop (p-location prop)))
244 (setf (p-seenp prop) t)
245 (values (coerce-property-value (p-value prop)
248 (p-location prop)))))))
250 (export 'add-property)
251 (defun add-property (pset name value &key type location)
252 "Add a property to PSET.
254 If a property with the same NAME already exists, report an error."
256 (with-default-error-location (location)
257 (let ((existing (get-property pset name nil)))
259 (error "Property ~S already defined~@[ at ~A~]"
260 name (p-location existing)))
261 (store-property pset name value :type type :location location))))
263 (export 'make-property-set)
264 (defun make-property-set (&rest plist)
265 "Make a new property set, with given properties.
267 This isn't the way to make properties when parsing, but it works well for
268 programmatic generation. The arguments should form a property list
269 (alternating keywords and values is good).
271 An attempt is made to guess property types from the Lisp types of the
272 values. This isn't always successful but it's not too bad. The
273 alternative is manufacturing a `property-value' object by hand and
274 stuffing it into the set."
276 (property-set plist))
278 (export 'property-set)
279 (defgeneric property-set (thing)
281 "Convert THING into a property set.")
282 (:method ((pset pset)) pset)
283 (:method ((list list))
284 "Convert a list into a property set. This works for alists and plists."
285 (multiple-value-bind (next name value)
286 (if (and list (consp (car list)))
287 (values #'cdr #'caar #'cdar)
288 (values #'cddr #'car #'cadr))
289 (do ((pset (make-pset))
290 (list list (funcall next list)))
292 (add-property pset (funcall name list) (funcall value list))))))
294 (export 'check-unused-properties)
295 (defun check-unused-properties (pset)
296 "Issue errors about unused properties in PSET."
298 (pset-map (lambda (prop)
299 (unless (p-seenp prop)
300 (cerror*-with-location (p-location prop)
301 "Unknown property `~A'"
303 (setf (p-seenp prop) t)))
306 ;;;--------------------------------------------------------------------------
309 (defmacro default-slot-from-property
310 ((instance slot &optional (slot-names t))
312 &optional (pvar (gensym "PROP-"))
315 "Initialize a slot from a property.
317 We initialize SLOT in INSTANCE. In full: if PSET contains a property
318 called NAME, then convert it to TYPE, bind the value to PVAR and evaluate
319 CONVERT-FORMS -- these default to just using the property value. If
320 there's no property, and DEFAULT-FORMS contains at least one non-
321 declaration form, and the slot is named in SLOT-NAMES and currently
322 unbound, then evaluate DEFAULT-FORMS and use their value to compute the
325 (once-only (instance slot slot-names pset property type)
326 (multiple-value-bind (docs decls body)
327 (parse-body default-forms :docp nil)
328 (declare (ignore docs))
330 `(multiple-value-bind (,pvar ,floc)
331 (get-property ,pset ,property ,type)
334 (setf (slot-value ,instance ,slot)
335 (with-default-error-location (,floc)
336 ,@(or convert-forms `(,pvar))))
338 `((default-slot (,instance ,slot ,slot-names)
341 ;;;----- That's all, folks --------------------------------------------------