X-Git-Url: https://git.distorted.org.uk/~mdw/sod/blobdiff_plain/ab7e7521a95d737ed6d1bf94964fc44d46ab077c..fddbedf7b1b4b19add30eeb62281748cc77e6955:/src/class-finalize-impl.lisp

diff --git a/src/class-finalize-impl.lisp b/src/class-finalize-impl.lisp
index f67c118..895b3c9 100644
--- a/src/class-finalize-impl.lisp
+++ b/src/class-finalize-impl.lisp
@@ -50,19 +50,65 @@
 
 ;;; Utilities.
 
+(export 'report-class-list-merge-error)
+(defun report-class-list-merge-error (class lists error)
+  "Report a failure to merge superclasseses.
+
+   Here, CLASS is the class whose class precedence list we're trying to
+   compute; the LISTS are the individual superclass orderings being merged;
+   and ERROR is an `inconsistent-merge-error' describing the problem that was
+   encountered.
+
+   Each of the LISTS is assumed to begin with the class from which the
+   corresponding constraint originates; see `merge-class-lists'."
+
+  (let* ((state (make-inheritance-path-reporter-state class))
+	 (candidates (merge-error-candidates error))
+	 (focus (remove-duplicates
+		 (remove nil
+			 (mapcar (lambda (list)
+				   (cons (car list)
+					 (remove-if-not
+					  (lambda (item)
+					    (member item candidates))
+					  list)))
+				 lists)
+			 :key #'cddr)
+		 :test #'equal :key #'cdr)))
+
+    (cerror*-with-location class "Ill-formed superclass graph: ~
+				  can't construct class precedence list ~
+				  for `~A'"
+			   class)
+    (dolist (offenders focus)
+      (let ((super (car offenders)))
+	(info-with-location super
+			    "~{Class `~A' orders `~A' before ~
+			       ~#[<BUG>~;`~A'~;`~A' and `~A'~:;~
+				  ~@{`~A', ~#[~;and `~A'~]~}~]~}"
+			    offenders)
+	(report-inheritance-path state super)))))
+
 (export 'merge-class-lists)
-(defun merge-class-lists (lists pick)
-  "Merge the LISTS of classes, using PICK to break ties.
+(defun merge-class-lists (class lists pick)
+  "Merge the LISTS of superclasses of CLASS, using PICK to break ties.
 
    This is a convenience wrapper around the main `merge-lists' function.
    Given that class linearizations (almost?) always specify a custom
-   tiebreaker function, this isn't a keyword argument.  Also, this wrapper
-   provides a standard presentation function so that any errors are presented
-   properly."
-  (merge-lists lists
-	       :pick pick
-	       :present (lambda (class)
-			  (format nil "`~A'" (sod-class-name class)))))
+   tiebreaker function, this isn't a keyword argument.
+
+   If a merge error occurs, this function translates it into a rather more
+   useful form, and tries to provide helpful notes.
+
+   For error reporting purposes, it's assumed that each of the LISTS begins
+   with the class from which the corresponding constraint originates.  This
+   initial class does double-duty: it is also considered to be part of the
+   list for the purpose of the merge."
+
+  (handler-case (merge-lists lists :pick pick)
+    (inconsistent-merge-error (error)
+      (report-class-list-merge-error class lists error)
+      (continue error))))
 
 ;;; Tiebreaker functions.
 
@@ -77,14 +123,11 @@
    direct subclass then that subclass's direct superclasses list must order
    them relative to each other."
 
-  (let (winner)
-    (dolist (class so-far)
-      (dolist (candidate candidates)
-	(when (member candidate (sod-class-direct-superclasses class))
-	  (setf winner candidate))))
-    (unless winner
-      (error "SOD INTERNAL ERROR: Failed to break tie in CLOS"))
-    winner))
+  (dolist (class (reverse so-far))
+    (dolist (candidate candidates)
+      (when (member candidate (sod-class-direct-superclasses class))
+	(return-from clos-tiebreaker candidate))))
+  (error "SOD INTERNAL ERROR: Failed to break tie in CLOS"))
 
 (defun c3-tiebreaker (candidates cpls)
   "The C3 linearization tiebreaker function.
@@ -133,11 +176,11 @@
 	       (remove-duplicates (cons class
 					(mappend #'superclasses
 						 direct-supers))))))
-    (merge-class-lists
-     (mapcar (lambda (class)
-	       (cons class (sod-class-direct-superclasses class)))
-	     (superclasses class))
-     #'clos-tiebreaker)))
+    (merge-class-lists class
+		       (mapcar (lambda (c)
+				 (cons c (sod-class-direct-superclasses c)))
+			       (superclasses class))
+		       #'clos-tiebreaker)))
 
 (export 'dylan-cpl)
 (defun dylan-cpl (class)
@@ -158,11 +201,11 @@
    assuming that the superclass CPLs are already monotonic.  If they aren't,
    you're going to lose anyway."
 
-  (let ((direct-supers (sod-class-direct-superclasses class)))
-    (merge-class-lists
-     (cons (cons class direct-supers)
-	   (mapcar #'sod-class-precedence-list direct-supers))
-     #'clos-tiebreaker)))
+  (let* ((direct-supers (sod-class-direct-superclasses class))
+	 (cpls (mapcar #'sod-class-precedence-list direct-supers)))
+    (merge-class-lists class
+		       (cons (cons class direct-supers) cpls)
+		       #'clos-tiebreaker)))
 
 (export 'c3-cpl)
 (defun c3-cpl (class)
@@ -179,7 +222,8 @@
 
   (let* ((direct-supers (sod-class-direct-superclasses class))
 	 (cpls (mapcar #'sod-class-precedence-list direct-supers)))
-    (merge-class-lists (cons (cons class direct-supers) cpls)
+    (merge-class-lists class
+		       (cons (cons class direct-supers) cpls)
 		       (lambda (candidates so-far)
 			 (declare (ignore so-far))
 			 (c3-tiebreaker candidates cpls)))))
@@ -242,7 +286,8 @@
 
   (let ((dfs (flavors-cpl class)))
     (cons class
-	  (merge-class-lists (mapcar #'sod-class-precedence-list
+	  (merge-class-lists class
+			     (mapcar #'sod-class-precedence-list
 				     (sod-class-direct-superclasses class))
 			     (lambda (candidates so-far)
 			       (declare (ignore so-far))
@@ -253,10 +298,7 @@
 ;;; Default function.
 
 (defmethod compute-cpl ((class sod-class))
-  (handler-case (c3-cpl class)
-    (inconsistent-merge-error ()
-      (error "Failed to compute class precedence list for `~A'"
-	     (sod-class-name class)))))
+  (c3-cpl class))
 
 ;;;--------------------------------------------------------------------------
 ;;; Chains.
@@ -297,187 +339,207 @@
 					 (cdr class-precedence-list)))))))))
 
 ;;;--------------------------------------------------------------------------
-;;; Metaclasses.
-
-(defmethod guess-metaclass ((class sod-class))
-  "Default metaclass-guessing function for classes.
-
-   Return the most specific metaclass of any of the CLASS's direct
-   superclasses."
-
-  ;; During bootstrapping, our superclasses might not have their own
-  ;; metaclasses resolved yet.  If we find this, then throw `bootstrapping'
-  ;; so that `shared-initialize' on `sod-class' can catch it (or as a shot
-  ;; across the bows of anyone else who calls us).
-  (finalization-error (:bad-metaclass)
-    (select-minimal-class-property (sod-class-direct-superclasses class)
-				   (lambda (super)
-				     (if (slot-boundp super 'metaclass)
-					 (slot-value super 'metaclass)
-					 (throw 'bootstrapping nil)))
-				   #'sod-subclass-p class "metaclass")))
-
-;;;--------------------------------------------------------------------------
 ;;; Sanity checking.
 
+(defmethod check-class-initializer ((slot effective-slot) (class sod-class))
+  (finalization-error (:missing-class-initializer)
+    (unless (find-class-initializer slot class)
+      (let ((dslot (effective-slot-direct-slot slot)))
+	(cerror* "Missing initializer for class slot `~A', ~
+		  defined by meta-superclass `~A' of `~A'"
+		 dslot (sod-slot-class dslot) class)))))
+
+(defmethod check-class-initializer
+    ((slot sod-class-effective-slot) (class sod-class))
+  ;; The programmer shouldn't set an explicit initializer here.
+  (finalization-error (:invalid-class-initializer)
+    (let ((init (find-class-initializer slot class))
+	  (dslot (effective-slot-direct-slot slot)))
+      (when init
+	(cerror* "Initializers not permitted for class slot `~A', ~
+		  defined by meta-superclass `~A' of `~A'"
+		 dslot (sod-slot-class dslot) class)
+	(info-with-location init "Offending initializer defined here")))))
+
 (defmethod check-sod-class ((class sod-class))
-  (with-default-error-location (class)
 
-    ;; Check the names of things are valid.
-    (flet ((check-list (list what namefunc)
-	     (dolist (item list)
-	       (let ((name (funcall namefunc item)))
-		 (unless (valid-name-p name)
-		   (cerror*-with-location item
-					  "Invalid ~A name `~A' ~
-					   in class `~A'"
-					  what name class))))))
-      (unless (valid-name-p (sod-class-name class))
-	(cerror* "Invalid class name `~A'" class))
-      (unless (valid-name-p (sod-class-nickname class))
-	(cerror* "Invalid class nickname `~A' for class `~A'"
-		 (sod-class-nickname class) class))
-      (check-list (sod-class-messages class) "message" #'sod-message-name)
-      (check-list (sod-class-slots class) "slot" #'sod-slot-name))
-
-    ;; Check that the class doesn't define conflicting things.
-    (labels ((check-list (list keyfunc complain)
-	       (let ((seen (make-hash-table :test #'equal)))
-		 (dolist (item list)
-		   (let* ((key (funcall keyfunc item))
-			  (found (gethash key seen)))
-		     (if found (funcall complain item found)
-			 (setf (gethash key seen) item))))))
-	     (simple-previous (previous)
-	       (info-with-location previous "Previous definition was here"))
-	     (simple-complain (what namefunc)
-	       (lambda (item previous)
+  ;; Check the names of things are valid.
+  (flet ((check-list (list what namefunc)
+	   (dolist (item list)
+	     (let ((name (funcall namefunc item)))
+	       (unless (valid-name-p name)
 		 (cerror*-with-location item
-					"Duplicate ~A `~A' in class `~A'"
-					what (funcall namefunc item) class)
-		 (simple-previous previous))))
-
-	;; Make sure direct slots have distinct names.
-	(check-list (sod-class-slots class) #'sod-slot-name
-		    (simple-complain "slot name" #'sod-slot-name))
-
-	;; Make sure there's at most one initializer for each slot.
-	(flet ((check-initializer-list (list kind)
-		 (check-list list #'sod-initializer-slot
-			     (lambda (initializer previous)
-			       (let ((slot
-				      (sod-initializer-slot initializer)))
-				 (cerror*-with-location initializer
-							"Duplicate ~
-							 initializer for ~
-							 ~A slot `~A' ~
-							 in class `~A'"
-							kind slot class)
-				 (simple-previous previous))))))
-	  (check-initializer-list (sod-class-instance-initializers class)
-				  "instance")
-	  (check-initializer-list (sod-class-class-initializers class)
-				  "class"))
-
-	;; Make sure messages have distinct names.
-	(check-list (sod-class-messages class) #'sod-message-name
-		    (simple-complain "message name" #'sod-message-name))
-
-	;; Make sure methods are sufficiently distinct.
-	(check-list (sod-class-methods class) #'sod-method-function-name
-		    (lambda (method previous)
-		      (cerror*-with-location method
-					     "Duplicate ~A direct method ~
-					      for message `~A' ~
-					      in classs `~A'"
-					     (sod-method-description method)
-					     (sod-method-message method)
-					     class)
-		      (simple-previous previous)))
-
-	;; Make sure superclasses have distinct nicknames.
-	(let ((state (make-inheritance-path-reporter-state class)))
-	  (check-list (sod-class-precedence-list class) #'sod-class-nickname
-		      (lambda (super previous)
-			(cerror*-with-location class
-					       "Duplicate nickname `~A' ~
-						in superclasses of `~A': ~
-						used by `~A' and `~A'"
-					       (sod-class-nickname super)
-					       class super previous)
-			(report-inheritance-path state super)
-			(report-inheritance-path state previous)))))
-
-    ;; Check that the CHAIN-TO class is actually a proper superclass.  (This
-    ;; eliminates hairy things like a class being its own link.)
-    (let ((link (sod-class-chain-link class)))
-      (unless (or (not link)
-		  (member link (cdr (sod-class-precedence-list class))))
-	(cerror* "In `~A~, chain-to class `~A' is not a proper superclass"
-		 class link)))
-
-    ;; Check that the initargs declare compatible types.  Duplicate entries,
-    ;; even within a class, are harmless, but at most one initarg in any
-    ;; class should declare a default value.
-    (let ((seen (make-hash-table :test #'equal))
-	  (state (make-inheritance-path-reporter-state class)))
-      (dolist (super (sod-class-precedence-list class))
-	(dolist (initarg (reverse (sod-class-initargs super)))
-	  (let* ((initarg-name (sod-initarg-name initarg))
-		 (initarg-type (sod-initarg-type initarg))
-		 (initarg-default (sod-initarg-default initarg))
-		 (found (gethash initarg-name seen))
-		 (found-type (and found (sod-initarg-type found)))
-		 (found-default (and found (sod-initarg-default found)))
-		 (found-class (and found (sod-initarg-class found)))
-		 (found-location (and found (file-location found))))
-	    (with-default-error-location (initarg)
-	      (cond ((not found)
-		     (setf (gethash initarg-name seen) initarg))
-		    ((not (c-type-equal-p initarg-type found-type))
-		     (cerror* "Inititalization argument `~A' defined ~
-			       with incompatible types: ~
-			       ~A in class `~A', but ~A in class `~A'"
-			      initarg-name initarg-type super
-			      found-type found-class found-location)
-		     (report-inheritance-path state super))
-		    ((and initarg-default found-default
-			  (eql super found-class))
-		     (cerror* "Initialization argument `~A' redefined ~
-			       with default value"
-			      initarg-name)
-		     (info-with-location found-location
-					 "Previous definition is here"))
-		    (initarg-default
-		     (setf (gethash initarg-name seen) initarg))))))))
-
-    ;; Check for circularity in the superclass graph.  Since the superclasses
-    ;; should already be acyclic, it suffices to check that our class is not
-    ;; a superclass of any of its own direct superclasses.
-    (let ((circle (find-if (lambda (super)
-			     (sod-subclass-p super class))
-			   (sod-class-direct-superclasses class))))
-      (when circle
-	(cerror* "`~A' is already a superclass of `~A'" class circle)
-	(report-inheritance-path (make-inheritance-path-reporter-state class)
-				 circle)))
-
-    ;; Check that the class has a unique root superclass.
-    (find-root-superclass class)
-
-    ;; Check that the metaclass is a subclass of each direct superclass's
-    ;; metaclass.
-    (finalization-error (:bad-metaclass)
-      (let ((meta (sod-class-metaclass class)))
-	(dolist (super (sod-class-direct-superclasses class))
-	  (let ((supermeta (sod-class-metaclass super)))
-	    (unless (sod-subclass-p meta supermeta)
-	      (cerror* "Metaclass `~A' of `~A' isn't a subclass of `~A'"
-		       meta class supermeta)
-	      (info-with-location super
-				  "Direct superclass `~A' defined here ~
-				   has metaclass `~A'"
-				  super supermeta))))))))
+					"Invalid ~A name `~A' in class `~A'"
+					what name class))))))
+    (unless (valid-name-p (sod-class-name class))
+      (cerror* "Invalid class name `~A'" class))
+    (unless (valid-name-p (sod-class-nickname class))
+      (cerror* "Invalid class nickname `~A' for class `~A'"
+	       (sod-class-nickname class) class))
+    (check-list (sod-class-messages class) "message" #'sod-message-name)
+    (check-list (sod-class-slots class) "slot" #'sod-slot-name))
+
+  ;; Check that the class doesn't define conflicting things.
+  (labels ((simple-previous (previous)
+	     (info-with-location previous "Previous definition was here"))
+	   (simple-complain (what namefunc)
+	     (lambda (item previous)
+	       (cerror*-with-location item
+				      "Duplicate ~A `~A' in class `~A'"
+				      what (funcall namefunc item) class)
+	       (simple-previous previous))))
+
+    ;; Make sure direct slots have distinct names.
+    (find-duplicates (simple-complain "slot name" #'sod-slot-name)
+		     (sod-class-slots class)
+		     :key #'sod-slot-name
+		     :test #'equal)
+
+    ;; Make sure there's at most one initializer for each slot.
+    (flet ((check-initializer-list (list kind)
+	     (find-duplicates (lambda (initializer previous)
+				(let ((slot
+				       (sod-initializer-slot initializer)))
+				  (cerror*-with-location initializer
+							 "Duplicate ~
+							  initializer ~
+							  for ~A slot `~A' ~
+							  in class `~A'"
+							 kind slot class)
+				  (simple-previous previous)))
+			      list
+			      :key #'sod-initializer-slot)))
+      (check-initializer-list (sod-class-instance-initializers class)
+			      "instance")
+      (check-initializer-list (sod-class-class-initializers class)
+			      "class"))
+
+    ;; Make sure messages have distinct names.
+    (find-duplicates (simple-complain "message name" #'sod-message-name)
+		     (sod-class-messages class)
+		     :key #'sod-message-name
+		     :test #'equal)
+
+    ;; Make sure methods are sufficiently distinct.
+    (find-duplicates (lambda (method previous)
+		       (cerror*-with-location method
+					      "Duplicate ~A direct method ~
+					       for message `~A' ~
+					       in classs `~A'"
+					      (sod-method-description method)
+					      (sod-method-message method)
+					      class)
+		       (simple-previous previous))
+		     (sod-class-methods class)
+		     :key #'sod-method-function-name
+		     :test #'equal)
+
+    ;; Make sure superclasses have distinct nicknames.
+    (let ((state (make-inheritance-path-reporter-state class)))
+      (find-duplicates (lambda (super previous)
+			 (cerror*-with-location class
+						"Duplicate nickname `~A' ~
+						 in superclasses of `~A': ~
+						 used by `~A' and `~A'"
+						(sod-class-nickname super)
+						class super previous)
+			 (report-inheritance-path state super)
+			 (report-inheritance-path state previous))
+		       (sod-class-precedence-list class)
+		       :key #'sod-class-nickname :test #'equal)))
+
+  ;; Check that the CHAIN-TO class is actually a proper superclass.  (This
+  ;; eliminates hairy things like a class being its own link.)
+  (let ((link (sod-class-chain-link class)))
+    (unless (or (not link)
+		(member link (cdr (sod-class-precedence-list class))))
+      (cerror* "In `~A', chain-to class `~A' is not a proper superclass"
+	       class link)))
+
+  ;; Check that the initargs declare compatible types.  Duplicate entries,
+  ;; even within a class, are harmless, but at most one initarg in any
+  ;; class should declare a default value.
+  (let ((seen (make-hash-table :test #'equal))
+	(state (make-inheritance-path-reporter-state class)))
+    (dolist (super (sod-class-precedence-list class))
+      (dolist (initarg (reverse (sod-class-initargs super)))
+	(let* ((initarg-name (sod-initarg-name initarg))
+	       (initarg-type (sod-initarg-type initarg))
+	       (initarg-default (sod-initarg-default initarg))
+	       (found (gethash initarg-name seen))
+	       (found-type (and found (sod-initarg-type found)))
+	       (found-default (and found (sod-initarg-default found)))
+	       (found-class (and found (sod-initarg-class found)))
+	       (found-location (and found (file-location found))))
+	  (with-default-error-location (initarg)
+	    (cond ((not found)
+		   (setf (gethash initarg-name seen) initarg))
+		  ((not (c-type-equal-p initarg-type found-type))
+		   (cerror* "Inititalization argument `~A' defined ~
+			     with incompatible types: ~
+			     ~A in class `~A', but ~A in class `~A'"
+			    initarg-name initarg-type super
+			    found-type found-class found-location)
+		   (report-inheritance-path state super))
+		  ((and initarg-default found-default
+			(eql super found-class))
+		   (cerror* "Initialization argument `~A' redefined ~
+			     with default value"
+			    initarg-name)
+		   (info-with-location found-location
+				       "Previous definition is here"))
+		  (initarg-default
+		   (setf (gethash initarg-name seen) initarg))))))))
+
+  ;; Check for circularity in the superclass graph.  Since the superclasses
+  ;; should already be acyclic, it suffices to check that our class is not
+  ;; a superclass of any of its own direct superclasses.
+  (let ((circle (find-if (lambda (super)
+			   (sod-subclass-p super class))
+			 (sod-class-direct-superclasses class))))
+    (when circle
+      (cerror* "`~A' is already a superclass of `~A'" class circle)
+      (report-inheritance-path (make-inheritance-path-reporter-state class)
+			       circle)))
+
+  ;; Check that the class has a unique root superclass.
+  (find-root-superclass class)
+
+  ;; Check that the metaclass is a subclass of each direct superclass's
+  ;; metaclass.
+  (finalization-error (:bad-metaclass)
+    (let ((meta (sod-class-metaclass class)))
+      (dolist (super (sod-class-direct-superclasses class))
+	(let ((supermeta (sod-class-metaclass super)))
+	  (unless (sod-subclass-p meta supermeta)
+	    (cerror* "Metaclass `~A' of `~A' isn't a subclass of `~A'"
+		     meta class supermeta)
+	    (info-with-location super
+				"Direct superclass `~A' defined here ~
+				 has metaclass `~A'"
+				super supermeta))))))
+
+  ;; Check that all of the messages we can be sent have coherent collections
+  ;; of applicable methods.  This can go wrong, for example, if we inherit
+  ;; methods with differently typed keyword arguments.
+  (finalization-error (:mismatched-applicable-methods)
+    (dolist (super (sod-class-precedence-list class))
+      (dolist (message (sod-class-messages super))
+	(let ((methods (sod-message-applicable-methods message class)))
+	  (sod-message-check-methods message class methods)))))
+
+  ;; Check that an initializer is available for every slot in the class's
+  ;; metaclass.  Skip this and trust the caller if the metaclass isn't
+  ;; finalized yet: in that case, we must be bootstrapping, and we must hope
+  ;; that the caller knows what they're doing.
+  (let* ((meta (sod-class-metaclass class))
+	 (ilayout (and (eq (sod-class-state meta) :finalized)
+		       (sod-class-ilayout meta))))
+    (dolist (ichain (and ilayout (ilayout-ichains ilayout)))
+      (dolist (item (cdr (ichain-body ichain)))
+	(when (typep item 'islots)
+	  (dolist (slot (islots-slots item))
+	    (check-class-initializer slot class)))))))
 
 ;;;--------------------------------------------------------------------------
 ;;; Finalization.
@@ -537,11 +599,6 @@
   ;; clone of the CPL and chain establishment code.  If the interface changes
   ;; then `bootstrap-classes' will need to be changed too.
 
-  ;; Set up the metaclass if it's not been set already.  This is delayed
-  ;; to give bootstrapping a chance to set up metaclass and superclass
-  ;; circularities.
-  (default-slot (class 'metaclass) (guess-metaclass class))
-
   ;; Finalize all of the superclasses.  There's some special pleading here to
   ;; make bootstrapping work: we don't try to finalize the metaclass if we're
   ;; a root class (no direct superclasses -- because in that case the