simonpj at microsoft.com
Thu Feb 9 03:19:00 EST 2006
| There has been a suggestion that the 'deriving' mechanism be
| from the datatype declaration. Together with a generic default
| definition, that means you could write something like
| deriving Bin for (,,,,,,,,,,,,,,,,,,,,)
| and hence not need to write the tedious instance header yourself,
| since the compiler can easily infer it.
Yes -- a couple of times I've nearly gotten down to implementing this.
Given that we have the deriving mechanism at all, we might as well make
it a bit more useful. The only real obstacle is defining a suitable
syntax. It makes the language bigger, but not in a deep way.
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