Tom wrote:

it has no extralogical operators (such as ones for performing I/O)

and commented:

This might not really be fair, since Twelf does have constraint domains, which I suppose could be used to implement I/O.

I changed the phrasing so that we say that the core does not contain extralogical operators, which I think is fine. --- Charles Stewart 20:31, 16 Jun 2005 (UTC)