+ scm_car ($2),
+ scm_cdr ($2));
+ }
+ ;
+
+// This is all quite awkward for the sake of substantial backward
+// compatibility while at the same time allowing a more "natural" form
+// of specification not separating grob specification from grob
+// property path. The purpose of this definition of revert_arg is to
+// allow the symbol list which specifies grob and property to revert
+// to be optionally be split into two parts after the grob (which in
+// this case is just the first element of the list). symbol_list_part
+// is only one path component, but it can be parsed without lookahead,
+// so we can follow it with a synthetic BACKUP token when needed. If
+// the first symbol_list_part already contains multiple elements (only
+// possible if a Scheme expression provides them), we just parse for
+// additional elements introduced by '.', which is what the
+// SYMBOL_LIST backup in connection with the immediately following
+// rule using symbol_list_arg does.
+//
+// As long as we don't have our coffers filled with both grob and at
+// least one grob property specification, the rest of the required
+// symbol list chain may be provided either with or without a leading
+// dot. This is for both allowing the traditional
+// \revert Accidental #'color
+// as well as well as the "naive" form
+// \revert Accidental.color
+
+revert_arg:
+ revert_arg_part
+ {
+ if (scm_is_null ($1)
+ || scm_is_null (scm_cdr ($1)))
+ MYBACKUP (SCM_ARG, $1, @1);
+ else
+ MYBACKUP (SYMBOL_LIST, scm_reverse_x ($1, SCM_EOL), @1);
+ }
+ | revert_arg BACKUP symbol_list_arg
+ {
+ $$ = $3;