X-Git-Url: https://git.distorted.org.uk/~mdw/sod/blobdiff_plain/0ad3667e905948b4bbade7a0da172c8cefcafad9..bfd08be5c65f696eddf48cfa48eaeab2714a3ec5:/src/lexer-proto.lisp

diff --git a/src/lexer-proto.lisp b/src/lexer-proto.lisp
index 22d61c0..a811298 100644
--- a/src/lexer-proto.lisp
+++ b/src/lexer-proto.lisp
@@ -112,6 +112,11 @@
 		      &rest token-types)
   "Discard tokens until we find one listed in TOKEN-TYPES.
 
+   Each of the TOKEN-TYPES is an expression which evaluates to either a
+   two-item list (TYPE VALUE), or a singleton TYPE; the latter is equivalent
+   to a list (TYPE t).  Such a pair matches a token with the corresponding
+   TYPE and VALUE, except that a VALUE of `t' matches any token value.
+
    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
@@ -124,7 +129,7 @@
 (export 'error)
 (defparse error (:context (context token-scanner-context)
 		 (&key ignore-unconsumed force-progress)
-		 sub &optional (recover t))
+		 sub &optional (recover t) &body body)
   "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
@@ -143,7 +148,8 @@
 			(parser () ,sub)
 			(parser () ,recover)
 			:ignore-unconsumed ,ignore-unconsumed
-			:force-progress ,force-progress))
+			:force-progress ,force-progress
+			:action ,(and body `(lambda () ,@body))))
 
 (export 'must)
 (defparse must (:context (context token-scanner-context)