On 8 okt 2006, at 18.22, Brian Smith wrote:
On 10/6/06, Björn Bringert <[EMAIL PROTECTED]> wrote:
John Hughes wrote:
> deriving (Eq Foo, Ord Foo)
>
> instead of
>
> deriving (Eq, Ord) for Foo
>
> I find the former syntax clearer and more readable, actually.
>
> John
I'll implement this syntax instead and then write up a Haskell'
proposal.
I am sure that it was already argued at great length, but I think
it is wrong to start the declaration with "deriving." I believe
that "derive instance" fits much better into the language. I
understand the desire to avoid adding new keywords but I think that
something along the lines of what was done for "for" could be done
here for "derive."
I agree that "derive" would be nicer, but as you say, the problem is
that it would add a new keyword. Since the declaration would then
start with "derive", I don't that think it could easily be made into
a special identifier. A deriving declaration would look like this:
derive Eq Foo
which looks just like the beginning of a declaration of a function
called "derive" which does some pattern matching, if derive can also
be an identifier.
/Björn
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