make ord() and chr() work with named args

src/core/Any-num.pm

@@ -12,7 +12,7 @@ augment class Any {
         pir::box__PN(pir::ceil__IN(self))
     }
 
-    our Str multi method chr() is export {
+    our Str multi method chr() {
         ~(pir::chr__SI(self))
     }
 
@@ -387,7 +387,7 @@ our multi sub sqrt(Any $x) {
 }
 
 our proto sign($x) {
-    defined($x) ?? $x.Num.sign !! undef;
+    defined($x) ?? $x.Num.sign !! Mu;
 }
 
 # This one doesn't seem to be needed with the above defined.
@@ -413,5 +413,8 @@ our multi sub infix:«<=>»($a, $b) {
     +$a cmp +$b
 }
 
+our proto chr($graph) {
+    $graph.chr;
+}
 
 # vim: ft=perl6

src/core/Any-str.pm

@@ -133,7 +133,7 @@ augment class Any {
         Regex::Cursor.parse(self, :rule($pat), :c($c));
     }
 
-    our Int multi method ord() is export {
+    our Int multi method ord() {
         fail('Can not take ord of empty string') if self.chars == 0;
         pir::box__PI(pir::ord__IS(self))
     }
@@ -179,6 +179,14 @@ augment class Any {
     }
 }
 
+our multi sub ord($string) {
+    $string.ord;
+}
+
+our proto ord($string) {
+    $string.ord;
+}
+
 multi sub infix:<x>($str, $n) {
     $n > 0 ?? ~(pir::repeat__SSI($str, $n)) !!  ''
 }