X-Git-Url: https://git.distorted.org.uk/~mdw/sod/blobdiff_plain/4fd69126f8b52945e0a572d1cf4a347468c1ced5..2b7ce7a531298ef50fe6fd98126485cc56175b02:/src/final.lisp

diff --git a/src/final.lisp b/src/final.lisp
index 1b87c26..e7a3eb4 100644
--- a/src/final.lisp
+++ b/src/final.lisp
@@ -74,29 +74,47 @@
 	      (values nil value)))))))
 
 (export 'test-parser)
-(defmacro test-parser ((scanner &key) parser input)
+(defmacro test-parser ((scanner &key backtrace) parser input)
   "Convenient macro for testing parsers at the REPL.
 
    This is a macro so that the parser can use the fancy syntax.  The name
    SCANNER is bound to a `sod-token-scanner' reading tokens from the INPUT
-   string.  Then the PARSER is invoked and three values are returned: a
-   `successp' flag indicating whether the parser succeeded; the result,
-   output or error indicator, of the parser; and a list consisting of the
-   lookahead token type and value, and a string containing the untokenized
-   remaining input."
+   string.  Then the PARSER is invoked and three values are returned: the
+   result of the parse, or `nil' if the main parse failed; a list containing
+   the number of errors and warnings (respectively) reported during the
+   parse; and a list consisting of the lookahead token type and value, and a
+   string containing the untokenized remaining input.
+
+   If BACKTRACE is nil (the default) then leave errors to the calling
+   environment to sort out (e.g., by entering the Lisp debugger); otherwise,
+   catch and report them as they happen so that you can test error recovery
+   strategies."
   (once-only (input)
-    (with-gensyms (char-scanner value winp consumedp where)
-      `(let* ((,char-scanner (make-string-scanner ,input))
-	      (,scanner (make-instance 'sod-token-scanner
-				       :char-scanner ,char-scanner
-				       :filename "<test-input>")))
+    (with-gensyms (char-scanner value winp body consumedp where nerror nwarn)
+      `(let ((,char-scanner nil) (,scanner nil))
 	 (with-parser-context (token-scanner-context :scanner ,scanner)
-	   (multiple-value-bind (,value ,winp ,consumedp) (parse ,parser)
-	     (declare (ignore ,consumedp))
+	   (multiple-value-bind (,value ,nerror ,nwarn)
+	       (flet ((,body ()
+			(setf ,char-scanner (make-string-scanner ,input)
+			      ,scanner (make-instance
+					'sod-token-scanner
+					:char-scanner ,char-scanner))
+			(multiple-value-bind (,value ,winp ,consumedp)
+			    (parse ,parser)
+			  (declare (ignore ,consumedp))
+			  (cond (,winp ,value)
+				(t (syntax-error ,scanner ,value)
+				   nil)))))
+		 (if ,backtrace (,body)
+		     (count-and-report-errors ()
+		       (with-default-error-location (,scanner)
+			 (,body)))))
 	     (let ((,where (scanner-capture-place ,char-scanner)))
-	       (values ,winp ,value
-		       (list (token-type ,scanner) (token-value ,scanner)
-			     (subseq ,input ,where))))))))))
+	       (values ,value
+		       (list ,nerror ,nwarn)
+		       (and ,scanner (list (token-type ,scanner)
+					   (token-value ,scanner)
+					   (subseq ,input ,where)))))))))))
 
 ;;;--------------------------------------------------------------------------
 ;;; Calisthenics.