Hi all,
I have just met a strange problem (it might have already been
answered, but I can't find the it) while using camlp4 to generate a
polymorphic type like:
type t = [ `A of int * int | `B of string ]
error msg "The present constructor A has a conjunctive type" is thrown
by the compiler.
I followed the ocaml source code, found in ocaml-3.10.2/typing/typetexp.ml
Line 290, it does the following check in add_field function:
if List.length stl > 1 || c && stl <> [] then
raise(Error(styp.ptyp_loc, Present_has_conjunction l));
Sorry, I can't fully understand the source code, but it seems we can
only define a polymorphic variant with only one additional type
declaration, like
`A of int or `A of (int * int)
rather than `A of int * int
It looks wired, as we can directly define
type t = [ `A of int * int | `B of string ] in toploop or a *.ml file.
Or I have some mis-understanding in this part.
Thanks for any help.
Best regards,
Conglun
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