On 04/22/2013 10:09 AM, Michael Norrish wrote:
On 22/04/13 4:29 PM, Andreas Rossberg wrote:
On Apr 22, 2013, at 03:31 , Michael Norrish
<[email protected]> wrote:
Is the following really supposed to be acceptable? Both Poly/ML and
mlton accept it without complaining:

datatype '+ = C | D;

(Moscow ML rejects it.  mlton and Poly/ML treat it as the
declaration of a unary type operator called +.)

and what about

datatype '' foo = C | D;

MLton and Poly/ML are correct. A type variable can be named plain '
or '', and symbolic identifiers (except *) are allowed as type
names.

Wow; you learn something new everyday.

Thanks for the quick feedback.

Incidentally, I think that makes your grammar at
http://www.mpi-sws.org/~rossberg/sml.html incorrect: the grammar there
wants an <id> to follow the apostrophe for <var>, and <id>s have at
least one character in them.

Yes, you are right. I was (semi-intentionally) sloppy there. Fixed.

Thanks,
/Andreas

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