Hi,

And a big thanks to everyone -- you've really given me a lot of interesting
ideas.  For the time being, I am going for the no-inheritance object solution:
it avoids the option type mess, provides a clean interface to users of the
module, and allows code reuse thanks to OCaml's structural subtyping feature
(the "duck" in this thread's title).  Moreover, while obviously not as concise
as a record, the declaration of each story variant is still quite economical:

class full (id, title, intro, body) =
object
        method id: int = id
        method title: string = title
        method intro: string = intro
        method body: string = body
end

class blurb (id, title, intro) =
object
        method id: int = id
        method title: string = title
        method intro: string = intro
end


Etc, etc.  I can live with this.

Cheers,
Dario





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