On 13-04-05 04:56 AM, Tom Ellis wrote:
any is very ambiguous. Doesn't the problem go away if you replace it with
all?
Yes, that is even better.
The world would be simple and elegant if it did things your way, and
would still be not too shabby if it did things my way, no?
«Learn You a
On Sat, Apr 06, 2013 at 05:14:48PM -0400, Albert Y. C. Lai wrote:
On 13-04-05 04:56 AM, Tom Ellis wrote:
any is very ambiguous. Doesn't the problem go away if you replace it with
all?
Yes, that is even better.
The world would be simple and elegant if it did things your way, and
would
On Thu, Apr 04, 2013 at 06:29:51PM -0400, Albert Y. C. Lai wrote:
You may think you know what's wrong, but you don't actually know
until you know how to clarify to the beginners. Note: harping on the
word any does not clarify, for the beginners exactly say this:
Yeah, t can be *any* type,
Albert Y. C. Lai trebla at vex.net writes:
Quantifiers are complicated, but I don't see how explicit is more so
than implicit. [...] I have just seen recently [...]
Great example. I completely agree.
My feeling is that mathematicians use this principle of leaving out
some of the
On Thu, Apr 04, 2013 at 11:02:34AM +, Johannes Waldmann wrote:
My feeling is that mathematicians use this principle of leaving out
some of the quantifiers and putting some others in the wrong place
as a cultural entry barrier to protect their field from newbies.
Albert showed an example
Hi,
Richard A. O'Keefe wrote:
As I understand it, in ML, it seemed to be a clever idea to not have type
signatures at all.
Wrong. In ML, it seemed to be a clever idea not to *NEED* type signatures,
and for local definitions they are very commonly omitted.
In the ML I used, I remember that
Tom Ellis tom-lists-haskell-cafe-2013 at jaguarpaw.co.uk writes:
I didn't see an example of quantifiers in the wrong place.
The example was:
every x satisfies P(x,y) for some y
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On Thu, Apr 04, 2013 at 01:15:27PM +, Johannes Waldmann wrote:
Tom Ellis tom-lists-haskell-cafe-2013 at jaguarpaw.co.uk writes:
I didn't see an example of quantifiers in the wrong place.
The example was:
every x satisfies P(x,y) for some y
Oh I see. I interpreted that as lack of
On 13-04-04 01:07 AM, wren ng thornton wrote:
When the quantifiers are implicit, we can rely on the unique human ability
to DWIM. This is a tremendous advantage when first teaching people about
mathematical concerns from a logical perspective. However, once people
move beyond the basics of
On 5/04/2013, at 1:22 AM, Tillmann Rendel wrote:
Hi,
Richard A. O'Keefe wrote:
As I understand it, in ML, it seemed to be a clever idea to not have type
signatures at all.
Wrong. In ML, it seemed to be a clever idea not to *NEED* type signatures,
and for local definitions they are
On Thu, Apr 4, 2013 at 3:29 PM, Albert Y. C. Lai tre...@vex.net wrote:
On 13-04-04 01:07 AM, wren ng thornton wrote:
When the quantifiers are implicit, we can rely on the unique human ability
to DWIM. This is a tremendous advantage when first teaching people about
mathematical concerns from
(Folks, let's rescue this increasingly tendentious thread.)
Some points to ponder:
(1) Any can be often be clarified to mean all, depending on how
polymorphic functions are exegeted. In a homotopy-flavored explanation
of natural transformation, its components (read parametric
instances) exist
I absolutely love to use Haskell when teaching
(and I have several years of experience doing it).
And I absolutely dislike it when I have to jump through hoops
to declare types in the most correct way, and in the most natural places.
This is hard to sell to the students. - Examples:
1. for
Hi Johannes.
I know this isn't really an answer, but ...
1. for explicit declaration of type variables, as in
reverse :: forall (a :: *) . [a] - [a]
I have to switch on RankNTypes and/or KindSignatures (ghc suggests).
... you can do this with ExplicitForall rather than RankNTypes,
which
Hi Johannes,
Johannes Waldmann wrote:
I absolutely dislike it when I have to jump through hoops
to declare types in the most correct way, and in the most natural places.
reverse :: forall (a :: *) . [a] - [a]
\ (xs :: [Bool]) - ...
All of this just because it seemed, at some time,
a clever
Hi Tillmann,
On Wed, Apr 3, 2013 at 11:59 PM, Tillmann Rendel
ren...@informatik.uni-marburg.de wrote:
From the type-theoretic point of view, I guess this is related to your view
of what a polymorphic function is.
Do you have a reference to the previous conversation?
but we moved further and
Hi Kim-Ee,
Kim-Ee Yeoh wrote:
[...] I guess this is related to your view of [...]
Do you have a reference to the previous conversation?
Sorry, I mean related to one's view of, not related to Johannes
Waldmanns' view of.
Which seems miles away from what you're alluding to. Full-blown
On 4/04/2013, at 5:59 AM, Tillmann Rendel wrote:
As I understand it, in ML, it seemed to be a clever idea to not have type
signatures at all.
Wrong. In ML, it seemed to be a clever idea not to *NEED* type signatures,
and for local definitions they are very commonly omitted.
But you can
On Wed, Apr 3, 2013 at 8:28 AM, Johannes Waldmann
waldm...@imn.htwk-leipzig.de wrote:
All of this just because it seemed, at some time,
a clever idea to allow the programmer to omit quantifiers?
(I know, mathematicians do this all over the place,
but it is never helpful, and especially not
On 13-04-03 07:39 PM, Alexander Solla wrote:
There's your problem. Mathematicians do this specifically because it is
helpful. If anything, explicit quantifiers and their interpretations
are more complicated. People seem to naturally get how scoping works in
mathematics until they have to
On 4/3/13 11:46 PM, Albert Y. C. Lai wrote:
On 13-04-03 07:39 PM, Alexander Solla wrote:
There's your problem. Mathematicians do this specifically because it is
helpful. If anything, explicit quantifiers and their interpretations
are more complicated. People seem to naturally get how
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