pugs-comm...@feather.perl6.nl wrote:
[S02] clarify that Pairs and Mappings are mutable in value, but not in key
     KeyHash     Perl hash that autodeletes values matching default
     KeySet      KeyHash of Bool (does Set in list/array context)
     KeyBag      KeyHash of UInt (does Bag in list/array context)
+    Pair        A single key-to-value association
+    Mapping     Set of Pairs with no duplicate keys
+As with C<Hash> types, C<Pair> and C<Mapping> are mutable in their
+values but not in their keys.  (A key can be a reference to a mutable
+object, but cannot change its C<.WHICH> identity.  In contrast,
+the value may be rebound to a different object, just as a hash
+element may.)

Following this change, it looks to me like Mapping is exactly the same as Hash. So under what circumstances should one now choose whether they want to use a Hash or a Mapping? How do they still differ? -- Darren Duncan

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