X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/sod/blobdiff_plain/e0808c472145fc81e52898bc9ac289e10c4f4f41..refs/heads/mdw/progfmt:/src/parser/scanner-proto.lisp

diff --git a/src/parser/scanner-proto.lisp b/src/parser/scanner-proto.lisp
index 8f27f89..aed4c9f 100644
--- a/src/parser/scanner-proto.lisp
+++ b/src/parser/scanner-proto.lisp
@@ -74,7 +74,7 @@ (defgeneric scanner-capture-place (scanner)
   (:documentation
    "Capture the SCANNER's current place and return it.")
   (:method (scanner)
-    (error "Scanner ~S doesn't support rewinding." scanner)))
+    (error "Scanner ~S doesn't support rewinding" scanner)))
 
 (export 'scanner-restore-place)
 (defgeneric scanner-restore-place (scanner place)
@@ -104,7 +104,7 @@ (defmacro with-scanner-place ((place scanner) &body body)
       `(let ((,place (scanner-capture-place ,scanner)))
 	 ,@decls
 	 (unwind-protect (progn ,@body)
-	   (scanner-release-place ,scanner ,place))))))
+	   (when ,place (scanner-release-place ,scanner ,place)))))))
 
 ;;;--------------------------------------------------------------------------
 ;;; Character scanner protocol.
@@ -157,6 +157,7 @@ (defgeneric scanner-column (scanner)
   (:documentation "Return the SCANNER's current column number.")
   (:method (scanner) nil))
 
+(export 'scanner-file-location)
 (defun scanner-file-location (scanner)
   "Capture the current location of the SCANNER.