> multi sub infix:<=.> (Str $w1 is rw, Str $w2) { $w1 = $w2 ~ $w1;}
sub infix:<=.> (Str $w1 is rw, Str $w2) { #`(Sub+{Precedence}|149632400) ... }
>
> my $c = "bar";
bar
> $c =. "foo";
foobar
> say $c;
foobar