src/lexer-impl.lisp: Don't always skip a token.

[sod] / src / lexer-impl.lisp

diff --git a/src/lexer-impl.lisp b/src/lexer-impl.lisp
index 821849b..f00994a 100644 (file)
--- a/src/lexer-impl.lisp
+++ b/src/lexer-impl.lisp
@@ -59,7 +59,8 @@
       (return (values token-types nil consumedp)))
     (scanner-step scanner)))
 
-(defun parse-error-recover (scanner parser recover &key ignore-unconsumed)
+(defun parse-error-recover (scanner parser recover
+                           &key ignore-unconsumed force-progress)
   "This is the implementation of the `error' parser."
   (multiple-value-bind (result win consumedp) (funcall parser)
     (cond ((or win
@@ -84,8 +85,8 @@
           ;; current token.  Finally, if we are at EOF then our best bet is
           ;; simply to propagate the current failure back to the caller, but
           ;; we handled that case above.
-          (syntax-error scanner result :continuep t)
-          (unless consumedp (scanner-step scanner))
+          (syntax-error scanner result)
+          (when (and force-progress (not consumedp)) (scanner-step scanner))
           (funcall recover)))))
 
 ;;;--------------------------------------------------------------------------