Marc Weber wrote:
http://impredicative.com/wiki/index.php/Polymorphic_Variants_Usage_Example
(* The commented out functions below do not compile .. the Medium constructor
is not polymorphic;
* it must "decide" on one of temp or size type
*)
[...snip...]
From reading the definitions in basis.urs I find it hard to find out how
to use them.
The code you quoted doesn't use polymorphic variants, which probably
explains why you found the definition of polymorphic variants unhelpful. ;)
Rather, the code you quoted uses normal ML variants, which are already
quite well accepted in SML, OCaml, and F#. Thus, I see no reason to
change the behavior. Just like with any other identifier in ML, it is
possible to shadow datatype constructor names, such that they literally
become unmentionable in future code. You can use modules as a namespace
mechanism to reuse constructor names, just as you can use this technique
to reuse any identifier.
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