More fun with undefined

Andreas Rossberg rossberg at
Fri Jun 15 00:09:03 PDT 2012

On 15 June 2012 01:22, Allen Wirfs-Brock <allen at> wrote:
> A wonder if this wart is hairy enough, that we wouldn't be justified in some
> explicit backwards compatibility hackery in the spec. to remove it.
> For example, we could allow it to appear in parameter lists and provide a
> dynamic check to ensure that nothing (other than a real undefined) is
> passed.  Similarly we could explicitly allow:
>       var undefined;

Actually, for very much the same effect, you could simply treat
'undefined' as a (refutable) _pattern_ that is only matched by the
undefined value. No need to make special rules for var or parameters


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