How lazy is DData.Seq?
wolfgang at jeltsch.net
Sat May 8 21:28:37 EDT 2004
Am Samstag, 8. Mai 2004 18:37 schrieben Sie:
> --- Wolfgang Jeltsch <wolfgang at jeltsch.net> wrote:
> > Hello,
> > I would suspect that in DData.Seq the result of
> > head (singleton 'a' `append` undefined)
> > is 'a' but instead it is _|_. Why is this the case?
> I have the invariant that sublists are not empty.
> There is, for example:
> append as None = as
Is this necessary/desirable? I have an application where I think that it can
be important for efficiency that the above expression evaluates to 'a'. So I
would like it to not result in _|_.
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