Max Skaller wrote:
>
> I'm confused: why doesn't this work? [I get unbound type ctor message]
> [shortened version]
>
> module type X = sig type one end
> module type Y = sig type two end
> module type XY = sig module type XX = X module type YY = Y end
> module type Client = functor (T: XY) ->
> sig val f: T.XX.one -> unit end
> ^^^^^^^^
>
> What I expected was that T.XX.one would refer to the
> type X.one, but this doesn't seem to be the case.
You cannot even say
type one = X.one
What you tried is just a more complicated example of the same thing.
Signature members cannot be accessed via the dot notation - it would not
make any sense. You cannot refer to X.one just as you cannot write
module type X = sig val one: int end
let one = X.one
Signatures just contain descriptions of entities - values, types,
modules, etc. - they do not contain the actual things. So there simply
is no type "X.one" if X is a signature, the notation does not even
exist. If you want to access an actual entity you need a structure that
matches the signature X.
I'm not sure what you were trying to do, maybe you meant to say
> module type XY = sig module XX : X module YY : Y end
? With this your example should be perfectly valid.
Hope this helps,
- Andreas
-- Andreas Rossberg, rossberg@ps.uni-sb.de:: be declarative. be functional. just be. ::
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