Add single-term prototype

The C<+> prototype is a special alternative to C<$> that will act like
C<\[@%]> when given a literal array or hash variable, but will otherwise
force scalar context on the argument.  This is useful for functions which
should accept either a literal array or an array reference as the argument:

    sub smartpush (+@) {
        my $aref = shift;
        die "Not an array or arrayref" unless ref $aref eq 'ARRAY';
        push @$aref, @_;
    }

When using the C<+> prototype, your function must check that the argument
is of an acceptable type.

1 files changed, 2 insertions, 2 deletions

diff --git a/toke.c b/toke.c
index ec2ac73c51..731c2b4d35 100644
--- a/toke.c
+++ b/toke.c
@@ -6523,7 +6523,7 @@ Perl_yylex(pTHX)
 			    (
 			        (
 			            *proto == '$' || *proto == '_'
-			         || *proto == '*'
+			         || *proto == '*' || *proto == '+'
 			        )
 			     && proto[1] == '\0'
 			    )
@@ -7735,7 +7735,7 @@ Perl_yylex(pTHX)
 			    if (warnillegalproto) {
 				if (must_be_last)
 				    proto_after_greedy_proto = TRUE;
-				if (!strchr("$@%*;[]&\\_", *p)) {
+				if (!strchr("$@%*;[]&\\_+", *p)) {
 				    bad_proto = TRUE;
 				}
 				else {