List syntax (was: Re: help from the community?)

Kirsten Chevalier catamorphism at
Fri Feb 2 23:17:01 EST 2007

On 2/2/07, Douglas Philips <dgou at> wrote:
> On 2007 Feb 2, at 1:03 PM, Neil Mitchell indited:
> > An import list is not a value, you can't examine whats in the list,
> > you can't enumerate it etc. As such, it doesn't really matter how many
> > elements are in there, the important thing is what the elements are.
> I don't know enough about it, but mightn't Template Haskell disagree
> on that point?
> Or any other source-level manipulators? (perhaps that shouldn't be a
> consideration?)

Well, Template Haskell is an extension and not part of the current
Haskell 98 standard. And as far as I know there's no effort to make it
part of Haskell Prime. So yeah, probably it shouldn't be a

> You just highlighted the inconsistency:
>         You refer to "import lists"... you appear to think of the import
> syntax _as a list_,
> and it is precisely that mental processing where the inconsistency
> hits/grates.
> If it is an "import" _list_ it can have trailing commas, but if it is
> some <other> _list_, it can't.
> I don't see the justification for making those two cases different.

The thing that I think Neil and Ganesh were trying to get at is that
an import list can't appear in just any context (that's what's meant
by it not being a first-class value), so Haskell programmers *do*
usually think about them differently.


Kirsten Chevalier* chevalier at *Often in error, never in doubt
"Man, you're not so perfect / Man, you're not a pearl / You're nothing
more, man, than a little piece of sand / That grew up inside of a girl"
-- Jude

More information about the Haskell-prime mailing list