Re: Persistence of limited tagged types

[Jano <nono@celes.unizar.es>]

Hyman Rosen dice...
> Stephen Leake wrote:
> > You will have to write a function that reads the external
> > representation of the tag, allocates an object of the appropriate
> > type, and returns the pointer. Yes, this function must be changed
> > every time you add a new tag.
> 
> This is known as the Factory pattern. Instead of changing the
> function for each new tag, you can have the package that defines
> the type enroll a read method into a table of methods. Then the
> factory reads the external tag representation, looks it up in
> the table, and calls the method if it's present.

I like this solution. With very little overwork.

-- 
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Jano
402450.at.cepsz.unizar.es
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