[Ur] {}

[Adam Chlipala]

Gergely Buday wrote:
>> Yes, though I'd say it the other way: [unit] is a synonym for [{}], which is
>> just a degenerate instance of the syntax for record types.  (I lifted this
>> convention directly from SML.)
>>      
> And, is there any reason to use either over the other in signatures, like
>
> transaction unit
>
> and
>
> transaction {}
>
> ?
>    

They have the same meaning.  Lately I've come to prefer the latter, and 
to regret including the synonym [unit].