Re: [bug #15690] Refactor /MISSING subcommands.

[Ben Pfaff]

John Darrington <address@hidden> writes:

> On Wed, Sep 27, 2006 at 07:48:25AM -0700, Benjamin Levy Pfaff wrote:
>      
>      OK.  Then let's create a new abstract data type, a "case_filter" or some
>      such.  To get a casereader with a filter, you pass one in, otherwise you
>      pass in a null pointer, so there's only a single additional argument. 
>      Cloned casereaders keep the same filter.  When no casereader or clone is
>      still using a filter, it gets destroyed; either reference counting or
>      case_filter cloning could be used.
>
> I've been looking at this again.  I don't think it will be necessary
> to abstract the case_filter.  A simple object containing an array of
> variables, and a bool to indicate whether user missing values should
> be excluded will, I think, be sufficient for all scenarios I can
> foresee.  If more complicated situations arise, then we can generalise
> a little, or abstract the type if and when that becomes necessary.   

Sounds OK.
-- 
On Perl: "It's as if H.P. Lovecraft, returned from the dead and speaking by
seance to Larry Wall, designed a language both elegant and terrifying for his
Elder Things to write programs in, and forgot that the Shoggoths didn't turn
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