;;;----- Licensing notice ---------------------------------------------------
;;;
-;;; This file is part of the Sensble Object Design, an object system for C.
+;;; This file is part of the Sensible Object Design, an object system for C.
;;;
;;; SOD is free software; you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
(,bodyfunc))))))))
(export 'parse-body)
-(defun parse-body (body)
+(defun parse-body (body &key (docp t) (declp t))
"Parse the BODY into a docstring, declarations and the body forms.
These are returned as three lists, so that they can be spliced into a
macro expansion easily. The declarations are consolidated into a single
- `declare' form."
+ `declare' form. If DOCP is nil then a docstring is not permitted; if
+ DECLP is nil, then declarations are not permitted."
(let ((decls nil)
(doc nil))
(loop
(cond ((null body) (return))
- ((and (consp (car body)) (eq (caar body) 'declare))
+ ((and declp (consp (car body)) (eq (caar body) 'declare))
(setf decls (append decls (cdr (pop body)))))
- ((and (stringp (car body)) (not doc) (cdr body))
+ ((and docp (stringp (car body)) (not doc) (cdr body))
(setf doc (pop body)))
(t (return))))
(values (and doc (list doc))
(and decls (list (cons 'declare decls)))
body)))
+;;;--------------------------------------------------------------------------
+;;; Locatives.
+
+(export '(loc locp))
+(defstruct (loc (:predicate locp) (:constructor make-loc (reader writer)))
+ "Locative data type. See `locf' and `ref'."
+ (reader nil :type function)
+ (writer nil :type function))
+
+(export 'locf)
+(defmacro locf (place &environment env)
+ "Slightly cheesy locatives.
+
+ (locf PLACE) returns an object which, using the `ref' function, can be
+ used to read or set the value of PLACE. It's cheesy because it uses
+ closures rather than actually taking the address of something. Also,
+ unlike Zetalisp, we don't overload `car' to do our dirty work."
+ (multiple-value-bind
+ (valtmps valforms newtmps setform getform)
+ (get-setf-expansion place env)
+ `(let* (,@(mapcar #'list valtmps valforms))
+ (make-loc (lambda () ,getform)
+ (lambda (,@newtmps) ,setform)))))
+
+(export 'ref)
+(declaim (inline ref (setf ref)))
+(defun ref (loc)
+ "Fetch the value referred to by a locative."
+ (funcall (loc-reader loc)))
+(defun (setf ref) (new loc)
+ "Store a new value in the place referred to by a locative."
+ (funcall (loc-writer loc) new))
+
+(export 'with-locatives)
+(defmacro with-locatives (locs &body body)
+ "Evaluate BODY with implicit locatives.
+
+ LOCS is a list of items of the form (SYM [LOC-EXPR]), where SYM is a
+ symbol and LOC-EXPR evaluates to a locative. If LOC-EXPR is omitted, it
+ defaults to SYM. As an abbreviation for a common case, LOCS may be a
+ symbol instead of a list.
+
+ The BODY is evaluated in an environment where each SYM is a symbol macro
+ which expands to (ref LOC-EXPR) -- or, in fact, something similar which
+ doesn't break if LOC-EXPR has side-effects. Thus, references, including
+ `setf' forms, fetch or modify the thing referred to by the LOC-EXPR.
+ Useful for covering over where something uses a locative."
+ (setf locs (mapcar (lambda (item)
+ (cond ((atom item) (list item item))
+ ((null (cdr item)) (list (car item) (car item)))
+ (t item)))
+ (if (listp locs) locs (list locs))))
+ (let ((tt (mapcar (lambda (l) (declare (ignore l)) (gensym)) locs))
+ (ll (mapcar #'cadr locs))
+ (ss (mapcar #'car locs)))
+ `(let (,@(mapcar (lambda (tmp loc) `(,tmp ,loc)) tt ll))
+ (symbol-macrolet (,@(mapcar (lambda (sym tmp)
+ `(,sym (ref ,tmp))) ss tt))
+ ,@body))))
+
;;;--------------------------------------------------------------------------
;;; Anaphorics.
((candidates :initarg :candidates
:reader merge-error-candidates))
(:documentation
- "Reports an inconsistency in the arguments passed to MERGE-LISTS.")
+ "Reports an inconsistency in the arguments passed to `merge-lists'.")
(:report (lambda (condition stream)
(format stream "Merge inconsistency: failed to decide among ~A."
(merge-error-candidates condition)))))
(defun merge-lists (lists &key pick (test #'eql))
"Return a merge of the given LISTS.
- The resulting LIST contains the items of the given lists, with duplicates
+ The resulting list contains the items of the given LISTS, with duplicates
removed. The order of the resulting list is consistent with the orders of
the input LISTS in the sense that if A precedes B in some input list then
A will also precede B in the output list. If the lists aren't consistent
If there is an ambiguity at any point -- i.e., a choice between two or
more possible next items to emit -- then PICK is called to arbitrate.
PICK is called with two arguments: the list of candidate next items, and
- the current output list. It should return one of the candidate items. If
- PICK is omitted then an arbitrary choice is made.
+ the current output list. It should return one of the candidate items.
+ The order of the candidates in the list given to the PICK function
+ reflects their order in the input LISTS: item A will precede item B in the
+ candidates list if and only if an occurrence of A appears in an earlier
+ input list than any occurrence of item B. (This completely determines the
+ order of the candidates: it is not possible that two candidates appear in
+ the same input list would resolve the ambiguity between them.) If PICK is
+ omitted then the item chosen is the one appearing in the earliest of the
+ input lists: i.e., effectively, the default PICK function is
+
+ (lambda (candidates output-so-far)
+ (declare (ignore output-so-far))
+ (car candidates))
The primary use of this function is in computing class precedence lists.
By building the input lists and selecting the PICK function appropriately,
a variety of different CPL algorithms can be implemented."
- (do* ((lb (make-list-builder)))
- ((null lists) (lbuild-list lb))
+ (do ((lb (make-list-builder)))
+ ((null lists) (lbuild-list lb))
;; The candidate items are the ones at the front of the input lists.
;; Gather them up, removing duplicates. If a candidate is somewhere in
;; one of the other lists other than at the front then we reject it. If
;; we've just rejected everything, then we can make no more progress and
;; the input lists were inconsistent.
- (let* ((candidates (delete-duplicates (mapcar #'car lists) :test test))
+ (let* ((candidates (delete-duplicates (mapcar #'car lists)
+ :test test :from-end t))
(leasts (remove-if (lambda (item)
(some (lambda (list)
(member item (cdr list) :test test))
(,print))
(,print)))))
+(export 'print-ugly-stuff)
+(defun print-ugly-stuff (stream func)
+ "Print not-pretty things to the stream underlying STREAM.
+
+ The Lisp pretty-printing machinery, notably `pprint-logical-block', may
+ interpose additional streams between its body and the original target
+ stream. This makes it difficult to make use of the underlying stream's
+ special features, whatever they might be."
+
+ ;; This is unpleasant. Hacky hacky.
+ #.(or #+sbcl '(if (typep stream 'sb-pretty:pretty-stream)
+ (let ((target (sb-pretty::pretty-stream-target stream)))
+ (pprint-newline :mandatory stream)
+ (funcall func target))
+ (funcall func stream))
+ #+cmu '(if (typep stream 'pp:pretty-stream)
+ (let ((target (pp::pretty-stream-target stream)))
+ (pprint-newline :mandatory stream)
+ (funcall func target))
+ (funcall func stream))
+ '(funcall func stream)))
+
;;;--------------------------------------------------------------------------
;;; Iteration macros.
(once-only (:environment env seq start end)
(with-gensyms ((ivar "INDEX-") (endvar "END-") (bodyfunc "BODY-"))
-
- (flet ((loopguts (indexp listp endvar)
- ;; Build a DO-loop to do what we want.
- (let* ((do-vars nil)
- (end-condition (if endvar
- `(>= ,ivar ,endvar)
- `(endp ,seq)))
- (item (if listp
- `(car ,seq)
- `(aref ,seq ,ivar)))
- (body-call `(,bodyfunc ,item)))
- (when listp
- (push `(,seq (nthcdr ,start ,seq) (cdr ,seq))
- do-vars))
- (when indexp
- (push `(,ivar ,start (1+ ,ivar)) do-vars))
- (when indexvar
- (setf body-call (append body-call (list ivar))))
- `(do ,do-vars (,end-condition) ,body-call))))
-
- `(block nil
- (flet ((,bodyfunc (,var ,@(and indexvar `(,indexvar)))
- (tagbody ,@body)))
+ (multiple-value-bind (docs decls body) (parse-body body :docp nil)
+ (declare (ignore docs))
+
+ (flet ((loopguts (indexp listp endvar)
+ ;; Build a DO-loop to do what we want.
+ (let* ((do-vars nil)
+ (end-condition (if endvar
+ `(>= ,ivar ,endvar)
+ `(endp ,seq)))
+ (item (if listp
+ `(car ,seq)
+ `(aref ,seq ,ivar)))
+ (body-call `(,bodyfunc ,item)))
+ (when listp
+ (push `(,seq (nthcdr ,start ,seq) (cdr ,seq))
+ do-vars))
+ (when indexp
+ (push `(,ivar ,start (1+ ,ivar)) do-vars))
+ (when indexvar
+ (setf body-call (append body-call (list ivar))))
+ `(do ,do-vars (,end-condition) ,body-call))))
+
+ `(block nil
+ (flet ((,bodyfunc (,var ,@(and indexvar `(,indexvar)))
+ ,@decls
+ (tagbody ,@body)))
(etypecase ,seq
(vector
(let ((,endvar (or ,end (length ,seq))))
(list
(if ,end
,(loopguts t t end)
- ,(loopguts indexvar t nil))))))))))
+ ,(loopguts indexvar t nil)))))))))))
;;;--------------------------------------------------------------------------
;;; Structure accessor hacks.
`((defun (setf ,from) (value object)
(setf (,to object) value))))))
-(export 'define-on-demand-slot)
-(defmacro define-on-demand-slot (class slot (instance) &body body)
- "Defines a slot which computes its initial value on demand.
-
- Sets up the named SLOT of CLASS to establish its value as the implicit
- progn BODY, by defining an appropriate method on `slot-unbound'."
- (with-gensyms (classvar slotvar)
- `(defmethod slot-unbound
- (,classvar (,instance ,class) (,slotvar (eql ',slot)))
- (declare (ignore ,classvar))
- (setf (slot-value ,instance ',slot) (progn ,@body)))))
-
;;;--------------------------------------------------------------------------
;;; CLOS hacking.
(setf (slot-value ,instance ,slot)
(progn ,@value)))))
+(export 'define-on-demand-slot)
+(defmacro define-on-demand-slot (class slot (instance) &body body)
+ "Defines a slot which computes its initial value on demand.
+
+ Sets up the named SLOT of CLASS to establish its value as the implicit
+ progn BODY, by defining an appropriate method on `slot-unbound'."
+ (multiple-value-bind (docs decls body) (parse-body body)
+ (with-gensyms (classvar slotvar)
+ `(defmethod slot-unbound
+ (,classvar (,instance ,class) (,slotvar (eql ',slot)))
+ ,@docs ,@decls
+ (declare (ignore ,classvar))
+ (setf (slot-value ,instance ',slot) (block ,slot ,@body))))))
+
;;;----- That's all, folks --------------------------------------------------
~mdw / sod / blobdiff