From: Mark Wooding <mdw@distorted.org.uk>
Date: Sun, 26 Mar 2017 14:16:18 +0000 (+0100)
Subject: src/module-parse.lisp: Improve error recovery for `class' item framing.
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/sod/commitdiff_plain/6362119ed7d736a6617f59f46ec98b6351cb9867

src/module-parse.lisp: Improve error recovery for `class' item framing.

Cope with a failure to parse the class name (by inventing a synthetic
name) and/or superclass list (by forcing the use of `SodObject' as a
parent).
---

diff --git a/src/module-parse.lisp b/src/module-parse.lisp
index 2d81de1..e175a5b 100644
--- a/src/module-parse.lisp
+++ b/src/module-parse.lisp
@@ -247,16 +247,30 @@ (define-pluggable-parser class-item initargs (scanner class pset)
 			#\,))
 		 (nil (must #\;)))))))
 
+(defun synthetic-name ()
+  "Return an obviously bogus synthetic not-identifier."
+  (let ((ix *temporary-index*))
+    (incf *temporary-index*)
+    (make-instance 'temporary-variable :tag (format nil "%%#~A" ix))))
+
 (defun parse-class-body (scanner pset name supers)
   ;; class-body ::= `{' class-item* `}'
   ;;
   ;; class-item ::= property-set raw-class-item
   (with-parser-context (token-scanner-context :scanner scanner)
-    (make-class-type name)
-    (let* ((duff nil)
-	   (class (make-sod-class name
+    (when name (make-class-type name))
+    (let* ((duff (null name))
+	   (synthetic-name (or name
+			       (let ((var (synthetic-name)))
+				 (unless pset
+				   (setf pset (make-property-set)))
+				 (unless (pset-get pset "nick")
+				   (add-property pset "nick" var :type :id))
+				 var)))
+	   (class (make-sod-class synthetic-name
 				  (restart-case
-				      (mapcar #'find-sod-class supers)
+				      (mapcar #'find-sod-class
+					      (or supers (list "SodObject")))
 				    (continue ()
 				      (setf duff t)
 				      (list (find-sod-class "SodObject"))))
@@ -419,11 +433,12 @@ (define-pluggable-parser module class (scanner pset)
   ;; `class' id `;'
   (with-parser-context (token-scanner-context :scanner scanner)
     (parse (seq ("class"
-		 (name :id)
+		 (name (must :id))
 		 (nil (or (seq (#\;)
-			    (make-class-type name))
-			  (seq ((supers (seq (#\: (ids (list () :id #\,)))
-					  ids))
+			    (when name (make-class-type name)))
+			  (seq ((supers (must (seq (#\:
+						    (ids (list () :id #\,)))
+						ids)))
 				(nil (parse-class-body
 				      scanner
 				      pset name supers)))))))))))