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On Thu, Aug 8, 2013 at 7:40 AM, Timon Gehr <[hidden email]> wrote:
I think
Jerzy is alluding to the fact that we don't have a denotational
semantics for IO. So I'm not sure I understand your response. Are you
pointing out that some subspace of IO programs admit such a semantics
via an easy inspection? 'putStr "c"' is a pure value.
This is the crux of the matter: "pure value" means different things to different people. Some employ it to mean an effectful monadic expression to distinguish between getLine and (return "Hello"), both of type IO String. Others use it to distinguish between an ordinary Haskell expression and, say, C. So when you write: > 'unsafePerformIO (putStr "c")' is not a pure value. Would you then speak of 'effectful' values vs 'nulleffectful' ones? What oral syntax would you actually use?  KimEe
On Thu, Aug 8, 2013 at 7:40 AM, Timon Gehr <[hidden email]> wrote:
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I have the impression that a nice part of our dispute comes from the
fact that despite our ambitions, and a decent /technical/ level of understanding of what we are talking about, most of us are (and I am one of the worst...)   pitiful philosophers... Really bad... Confusing the contents and the function/role of the entities, using ambiguous definitions (and confounding objects with their definitions), et j'en passe. Sigh. I decided to reread some philosophical texts, and I suggest one for your evening reading. "Indiscrete Thoughts" by GianCarlo Rota, published by Birkhäuser in 1997. Available on the Web. Rota was an active *mathematician* and teacher, and the sense of mathematical constructs was very important for him. It is a very refreshing book, you won't be disappointed. (It contains also some personal views of Rota on his fellows mathematicians. And the analysis of the difference between characters who are "problem solvers", as contrasted with "theoreticians"... Rota was a strong personality, full of "obsessions", and his ideas on the soundness of formal thinking may not convince you, but you should find them interesting. And you will find inside that for Rota the term "should" is very important, even if it impossible to define...) Many thanks to Olivier Danvy, who recommended me this book! Jerzy Karczmarczuk Caen, France. _______________________________________________ HaskellCafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskellcafe 
On Fri, Aug 9, 2013 at 5:44 PM, Jerzy Karczmarczuk <[hidden email]> wrote: I have the impression that a nice part of our dispute comes from the fact that despite our ambitions, and a decent /technical/ level of understanding of what we are talking about, most of us are (and I am one of the worst...)  I just leave this here, happy hacking... man _______________________________________________ HaskellCafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskellcafe 
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In reply to this post by Jerzy Karczmarczuk
On Fri, Aug 9, 2013 at 10:44 PM, Jerzy Karczmarczuk <[hidden email]> wrote:
I'm rather fond of Rota's two volumes of musings. For the purpose of furthering the quality of philosophizing, would it not be better served citing the relevant chapters, if not the actual page numbers? As you took note, the book covers a swathe of topics.  KimEe
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KimEe Yeoh comments my reading
suggestion:
Shall I also give the line numbers, KimEe? The book of Rota is divided into parts and chapters, with titles. It is not so difficult to find quickly that something may (or not) interest you. What is a "relevant" chapter in a collection of philosophical essays? You might skip the "biographies" of some mathematicians, with some unpleasant fragments, if you are not interested. I liked a few others. Part II, Ch. VII: "The Pernicious Influence of Mathematics Upon Philosophy" is an inspired attack addressed at the "analytical philosophers" who felt really offended! (This is a reprint from the Journal of Metaphysics, published also in the book "18 Unconventional Essays on the Nature of Mathematics", Springer, ed. by Reuben Hersh. I also recommend it [also on the Web], it is plenty of serious wisdom, although sometimes hard to read.) This chapter deals with the nonphilosophical essence of logic, with the "philosophical vacuity" of formal definitions. Very inspiring. For Rota the question of IDENTITY is more important than that of EXISTENCE. The chapter XII: "Syntax, Semantics, and the Problem of the Identity of Mathematical Items" (p. 151) begins his presentation of the subject, which continues later. Rota exposes some reasoning based on his favourite philosophical topic, the phenomenology, continuing previous sections. This may not convince you (e.g. if you are an orthodox materialist...), but you might learn something. The chapter about /Fundierung/ (XV, p. 172) in which Rota fights against the reductionism, may give you a headache. But you should survive. Anyway, /a ciascuno il suo/. Jerzy K. _______________________________________________ HaskellCafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskellcafe 
In reply to this post by Jerzy Karczmarczuk
On 09.08.2013 17:44, Jerzy Karczmarczuk wrote:
> "Indiscrete Thoughts" by GianCarlo Rota, published by Birkhäuser in > 1997. Available on the Web. For download or to buy? [This looks very interesting...]  Andreas Abel <>< Du bist der geliebte Mensch. Theoretical Computer Science, University of Munich Oettingenstr. 67, D80538 Munich, GERMANY [hidden email] http://www2.tcs.ifi.lmu.de/~abel/ _______________________________________________ HaskellCafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskellcafe 
In reply to this post by Adam Gundry
On 06.08.2013 10:46, Adam Gundry wrote:
> On 06/08/13 06:14, J. Stutterheim wrote: >> Suppose we now have the opportunity to change the name of the >> `return` function in Monad, what would be a "better" name for it? >> (for some definition of better) > > Rather than proposing a different name, I'm going to challenge the > premise of your question. Perhaps it would be better if `return` had no > name at all. Consider the following: > > return f `ap` s `ap` t > > f <$> s <*> t > > do { sv < s > ; tv < t > ; return (f sv tv) } Indeed, I wished the 0ary case would be more alike to the unary and binary case, cf. return f0 f1 <$> a1 f2 <$> a1 <*> a2 What is needed is a nice syntax for "idiom brackets". > These are all different ways of spelling > > f s t > > plus the necessary applicative or monadic bureaucracy. But why couldn't > we write just the plain application, and let the type system deal with > the plumbing of effects? I would not think this is practically possible. For instance, if f :: a > b > c then it could be a binary function or a unary function in the context monad reading from a, thus, application f x is ambiguous or too sensitive, especially with type inference. > I realise that this may be too open a research area for your project...  Andreas Abel <>< Du bist der geliebte Mensch. Theoretical Computer Science, University of Munich Oettingenstr. 67, D80538 Munich, GERMANY [hidden email] http://www2.tcs.ifi.lmu.de/~abel/ _______________________________________________ HaskellCafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskellcafe 
On 13/08/13 17:38, Andreas Abel wrote:
> Indeed, I wished the 0ary case would be more alike to the unary and binary > case, cf. > > return f0 > f1 <$> a1 > f2 <$> a1 <*> a2 You could always write the above as pure f0 pure f1 <*> a1 pure f2 <*> a1 <*> a2 Twan _______________________________________________ HaskellCafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskellcafe 
In reply to this post by Andreas Abel
 Indeed, I wished the 0ary case would be more alike to the unary and
 binary case, cf.   return f0  f1 <$> a1  f2 <$> a1 <*> a2   What is needed is a nice syntax for "idiom brackets". Indeed. I'm quite open to adding idiom brackets to GHC, if everyone can agree on their syntax, and someone would like to offer a patch. Something like ( f a1 a2 ) perhaps? Simon _______________________________________________ HaskellCafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskellcafe 
On Wed, Aug 14, 2013 at 7:54 PM, Simon PeytonJones <[hidden email]> wrote:
The last time I suggested this (on IRC), the first question someone asked was: How should nested uses of applicative work with idiom brackets? I think this question actually comes in two flavors:
* Can you nest the brackets themselves? * How deeply do you traverse the expression to insert the applicative combinators? Also, if anyone wants to look at prior art first, Idris supports applicative brackets.
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On Thu, Aug 15, 2013 at 5:39 AM, Jason Dagit <[hidden email]> wrote:
> Also, if anyone wants to look at prior art first, Idris supports applicative > brackets. As does she [0]. Erik [0] https://personal.cis.strath.ac.uk/conor.mcbride/pub/she/idiom.html _______________________________________________ HaskellCafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskellcafe 
I particularly like she's (her?) syntax for Alternative. Not sure whether or not Idris has that. Applicative tuples would be nice too, something like On Thu, Aug 15, 2013 at 11:08 AM, Erik Hesselink <[hidden email]> wrote:
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In reply to this post by Simon Peyton Jones
Simon PeytonJones <[hidden email]> writes:
>  Indeed, I wished the 0ary case would be more alike to the unary >  and binary case, cf. >  >  return f0 >  f1 <$> a1 >  f2 <$> a1 <*> a2 >  >  What is needed is a nice syntax for "idiom brackets". > > Indeed. I'm quite open to adding idiom brackets to GHC, if everyone > can agree on their syntax, and someone would like to offer a patch. > > Something like > ( f a1 a2 ) > perhaps? I can make a patch after people agree on everything. There's also http://hackage.haskell.org/package/applicativequoters with its template haskell nastiness h> :m +Control.Applicative.QQ.Idiom h> :set XQuasiQuotes h> [i (,) "THX" "BYE" ] [('T','B'),('T','Y'),('T','E'),('H','B'),('H','Y'),('H','E'),('X','B'),('X','Y'),('X','E')]  lelf _______________________________________________ HaskellCafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskellcafe 
If we're adding applicative brackets, it would be nice to have something like ⦇⦈ as options via UnicodeSyntax. When playing around with She, I found it much easier to read than the ASCII version, especially when I needed to combine them: ((a + b) + (c * d))On Thu, Aug 15, 2013 at 10:44 AM, Anton Nikishaev <[hidden email]> wrote:
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In reply to this post by Dag Odenhall
Dag Odenhall <[hidden email]> writes:
> I particularly like she's (her?) syntax for Alternative. Not sure > whether or not Idris has that. Applicative tuples would be nice too, > something like (a,b,c) translating to liftA3 (,,) a b c. And > operators too, liftA2 (+) a b as ( a + b )? > I patched she and did applicative tuples. Check my recent blog post on it: http://blog.bezirg.net/posts/20130803enhancementtothestrathclydehaskellenhancement.html She already does lifting of binary operators, AFAIK. Cheers > > > On Thu, Aug 15, 2013 at 11:08 AM, Erik Hesselink <[hidden email] >> wrote: > > On Thu, Aug 15, 2013 at 5:39 AM, Jason Dagit <[hidden email]> > wrote: > > Also, if anyone wants to look at prior art first, Idris > supports applicative > > brackets. > > As does she [0]. > > Erik > > [0] https://personal.cis.strath.ac.uk/conor.mcbride/pub/she/ > idiom.html > > _______________________________________________ > HaskellCafe mailing list > [hidden email] > http://www.haskell.org/mailman/listinfo/haskellcafe > > > > > _______________________________________________ > HaskellCafe mailing list > [hidden email] > http://www.haskell.org/mailman/listinfo/haskellcafe _______________________________________________ HaskellCafe mailing list [hidden email] http://www.haskell.org/mailman/listinfo/haskellcafe 
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