X-Git-Url: https://git.distorted.org.uk/~mdw/sod/blobdiff_plain/c91b90c3bfd3d3e68cc3d3ff3f431d1e73920061..048d0b2d143b6a491ac73eed6ab972e97774391c:/src/lexer-proto.lisp

diff --git a/src/lexer-proto.lisp b/src/lexer-proto.lisp
index e72152e..af2e535 100644
--- a/src/lexer-proto.lisp
+++ b/src/lexer-proto.lisp
@@ -56,6 +56,7 @@
 		 (format nil "~/sod::show-char/" type)
 		 (case type
 		   (:id (format nil "<identifier~@[ `~A'~]>" value))
+		   (:int "<integer-literal>")
 		   (:string "<string-literal>")
 		   (:char "<character-literal>")
 		   (:eof "<end-of-file>")
@@ -95,6 +96,36 @@
 		(scanner-current-char char-scanner))
 	   (and consumedp (file-location char-scanner))))
 
+(defparse skip-until (:context (context token-scanner-context)
+		      (&key (keep-end nil keep-end-p))
+		      &rest token-types)
+  "Discard tokens until we find one listed in TOKEN-TYPES.
+
+   If KEEP-END is true then retain the found token for later; otherwise
+   discard it.  KEEP-END defaults to true if multiple TOKEN-TYPES are given;
+   otherwise false.  If end-of-file is encountered then the indicator list is
+   simply the list of TOKEN-TYPES; otherwise the result is `nil'."
+  `(skip-until ,(parser-scanner context)
+	       (list ,@token-types)
+	       :keep-end ,(if keep-end-p keep-end
+			      (> (length token-types) 1))))
+
+(defparse error (:context (context token-scanner-context)
+		 (&key) sub &optional (recover t))
+  "Try to parse SUB; if it fails then report an error, and parse RECOVER.
+
+   This is the main way to recover from errors and continue parsing.  Even
+   then, it's not especially brilliant.
+
+   If the SUB parser succeeds then just propagate its result: it's like we
+   were never here.  Otherwise, try to recover in a sensible way so we can
+   continue parsing.  The details of this recovery are subject to change, but
+   the final action is generally to invoke the RECOVER parser and return its
+   result."
+  `(parse-error-recover ,(parser-scanner context)
+			(parser () ,sub)
+			(parser () ,recover)))
+
 ;;;--------------------------------------------------------------------------
 ;;; Lexical analysis utilities.