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| -rw-r--r-- | perl6.html.markdown | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/perl6.html.markdown b/perl6.html.markdown index cb64b646..6b0df0d4 100644 --- a/perl6.html.markdown +++ b/perl6.html.markdown @@ -247,11 +247,12 @@ concat3(|@array); #=> a, b, c ## arguments. If you really need to, you can ask for a mutable container by ## using the `is rw` trait: sub mutate( $n is rw ) { - $n++; + $n++; # postfix ++ operator increments its argument but returns its old value } my $m = 42; -mutate $m; #=> 43 +mutate $m; # the value is incremented but the old value is returned + #=> 42 say $m; #=> 43 ## This works because we are passing the container $m to the `mutate` sub. |