date:20131106

Annotations

2013-11-06 Thread Simon Peyton-Jones

I've just noticed that there is no GHC language extension for annotations
http://www.haskell.org/ghc/docs/latest/html/users_guide/extending-ghc.html#annotation-pragmas
That feels like an oversight. Yes, they are in a pragma, but you may get an 
error message if you compile with a stage-1 compiler, for example.  Plus, the 
language extensions should truthfully report what extra stuff you are using.

I'm inclined to add a language extension Annotations.

* Without it {-# ANN ... #-} pragmas are ignored as comments

* With it, they are treated as annotations
Do you agree?
I don't know whether this can (or even should) land in 7.8.1.  Do you care 
either way?
Guidance welcome
Simon

Microsoft Research Limited (company number 03369488) is registered in England 
and Wales
Registered office is at 21 Station Road, Cambridge, CB1 2FB

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Re: Annotations

2013-11-06 Thread Gergely Risko

On Wed, 6 Nov 2013 10:55:09 +, Simon Peyton-Jones simo...@microsoft.com 
writes:

 I’m inclined to add a language extension “Annotations”. 

 · Without it {-# ANN … #-} pragmas are ignored as comments

 · With it, they are treated as annotations

 Do you agree?

I generally agree that this should be a language extension.

My only worry is around the just implemented TH additions regarding
annotations.  I don't clearly see what would happen if:
  - a TH library exports a function that generates annotations when spliced.
  - and the user uses this function in a .hs file,
  - without specifying the language extension.

I'd it to work even in that case.

I guess the behavior in this corner case depends heavily on how this is
actually implemented.  If e.g. the reader is the only component that
checks if the language extension is turned on, then I imagine that the
TH way of putting in the annotation into the AST would just work.

On the other hand if the reader recognizes the annotations either way
and some component after TH splicing is checking for the language
extension, then my use-case would blow up.

TH currently is lenient in cases like this.  E.g. if you know that a
Name is exported from a module and you reference it directly, without
importing it everything will just work.  I'd like to have the same
behavior for annotations.

Thanks,
Gergely

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RE: Annotations

2013-11-06 Thread Simon Peyton-Jones

| My only worry is around the just implemented TH additions regarding
| annotations.  I don't clearly see what would happen if:
|   - a TH library exports a function that generates annotations when
| spliced.  
|   - and the user uses this function in a .hs file,
|   - without specifying the language extension.

But this is true for ANY language extension. If a TH library exports a function 
that generates (say) a type family declaration, and you splice that into a 
file, do you need -XTypeFamilies in the client file?   I think currently you 
do.  

So your point is a good one but it's orthogonal.

Simon

| -Original Message-
| From: ghc-devs [mailto:ghc-devs-boun...@haskell.org] On Behalf Of
| Gergely Risko
| Sent: 06 November 2013 11:57
| To: ghc-d...@haskell.org
| Cc: glasgow-haskell-users@haskell.org
| Subject: Re: Annotations
| 
| On Wed, 6 Nov 2013 10:55:09 +, Simon Peyton-Jones
| simo...@microsoft.com writes:
| 
|  I’m inclined to add a language extension “Annotations”.
| 
|  · Without it {-# ANN … #-} pragmas are ignored as comments
| 
|  · With it, they are treated as annotations
| 
|  Do you agree?
| 
| I generally agree that this should be a language extension.
| 
| My only worry is around the just implemented TH additions regarding
| annotations.  I don't clearly see what would happen if:
|   - a TH library exports a function that generates annotations when
| spliced.  
|   - and the user uses this function in a .hs file,
|   - without specifying the language extension.
| 
| I'd it to work even in that case.
| 
| I guess the behavior in this corner case depends heavily on how this is
| actually implemented.  If e.g. the reader is the only component that
| checks if the language extension is turned on, then I imagine that the
| TH way of putting in the annotation into the AST would just work.
| 
| On the other hand if the reader recognizes the annotations either way
| and some component after TH splicing is checking for the language
| extension, then my use-case would blow up.
| 
| TH currently is lenient in cases like this.  E.g. if you know that a
| Name is exported from a module and you reference it directly, without
| importing it everything will just work.  I'd like to have the same
| behavior for annotations.
| 
| Thanks,
| Gergely
| 
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| ghc-d...@haskell.org
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Re: Annotations

2013-11-06 Thread Edward A Kmett

Currently, in all the cases I can think of if the splice generates something 
that uses an extension then the module must have that flag turned on.

Sent from my iPhone

 On Nov 6, 2013, at 6:57 AM, Gergely Risko gerg...@risko.hu wrote:
 
 On Wed, 6 Nov 2013 10:55:09 +, Simon Peyton-Jones simo...@microsoft.com 
 writes:
 
 I’m inclined to add a language extension “Annotations”. 
 
 · Without it {-# ANN … #-} pragmas are ignored as comments
 
 · With it, they are treated as annotations
 
 Do you agree?
 
 I generally agree that this should be a language extension.
 
 My only worry is around the just implemented TH additions regarding
 annotations.  I don't clearly see what would happen if:
  - a TH library exports a function that generates annotations when spliced.
  - and the user uses this function in a .hs file,
  - without specifying the language extension.
 
 I'd it to work even in that case.
 
 I guess the behavior in this corner case depends heavily on how this is
 actually implemented.  If e.g. the reader is the only component that
 checks if the language extension is turned on, then I imagine that the
 TH way of putting in the annotation into the AST would just work.
 
 On the other hand if the reader recognizes the annotations either way
 and some component after TH splicing is checking for the language
 extension, then my use-case would blow up.
 
 TH currently is lenient in cases like this.  E.g. if you know that a
 Name is exported from a module and you reference it directly, without
 importing it everything will just work.  I'd like to have the same
 behavior for annotations.
 
 Thanks,
 Gergely
 
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Re: love for hpc?

2013-11-06 Thread Carter Schonwald

Evan,

if  you want to get involved in working on HPC, go for it! theres many many
pieces of ghc that need more proactive ownership.

i should probably use HPC a bit as i start getting my numerical libs out,
and i'm sure future me will appreciate current you working on making it
better

-Carter


On Thu, Nov 7, 2013 at 12:03 AM, Evan Laforge qdun...@gmail.com wrote:

 Is anyone out there using HPC?  It seems like it was gotten into a
 more or less working if not ideal state, and then abandoned.

 Things I've noticed lately:

 The GHC runtime just quits on the spot if there's already a tix file.
 This bit me when I was parallelizing tests.  It's also completely
 unsafe when run concurrently, mostly it just overwrites the file,
 sometimes it quits.  Sure to cause headaches for someone trying to
 parallelize tests.

 You can't change the name of the output tix file, so I worked around
 by hardlinking the binary to a bunch of new ones, and then doing 'hpc
 sum' on the results.

 The hpc command is super slow.  It might have to do with it doing its
 parsing with Prelude's 'read', and it certainly doesn't help the error
 msgs.

 And the whole thing is generally minimally documented.

 I can already predict the answer will be yes, HPC could use some
 love, roll up your sleeves and welcome!  It does look like it could
 be improved a lot with just a bit of effort, but that would be a yak
 too far for me, at the moment.  I'm presently just curious if anyone
 else out there is using it, and if they feel like it could do with a
 bit of polishing.
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Re: love for hpc?

2013-11-06 Thread Roman Cheplyaka

So Evan's prediction was accurate ;-)

* Carter Schonwald carter.schonw...@gmail.com [2013-11-07 00:29:24-0500]
 Evan,
 
 if  you want to get involved in working on HPC, go for it! theres many many
 pieces of ghc that need more proactive ownership.
 
 i should probably use HPC a bit as i start getting my numerical libs out,
 and i'm sure future me will appreciate current you working on making it
 better
 
 -Carter
 
 
 On Thu, Nov 7, 2013 at 12:03 AM, Evan Laforge qdun...@gmail.com wrote:
 
  Is anyone out there using HPC?  It seems like it was gotten into a
  more or less working if not ideal state, and then abandoned.
 
  Things I've noticed lately:
 
  The GHC runtime just quits on the spot if there's already a tix file.
  This bit me when I was parallelizing tests.  It's also completely
  unsafe when run concurrently, mostly it just overwrites the file,
  sometimes it quits.  Sure to cause headaches for someone trying to
  parallelize tests.
 
  You can't change the name of the output tix file, so I worked around
  by hardlinking the binary to a bunch of new ones, and then doing 'hpc
  sum' on the results.
 
  The hpc command is super slow.  It might have to do with it doing its
  parsing with Prelude's 'read', and it certainly doesn't help the error
  msgs.
 
  And the whole thing is generally minimally documented.
 
  I can already predict the answer will be yes, HPC could use some
  love, roll up your sleeves and welcome!  It does look like it could
  be improved a lot with just a bit of effort, but that would be a yak
  too far for me, at the moment.  I'm presently just curious if anyone
  else out there is using it, and if they feel like it could do with a
  bit of polishing.
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[Haskell] Haskell Weekly News: Issue 285

2013-11-06 Thread Daniel Santa Cruz

Welcome to issue 285 of the HWN, an issue covering crowd-sourced bits
of information about Haskell from around the web. This issue covers the
weeks of October 20 to November 02, 2013.

Quotes of the Week

   * roconnor: edwardk: is comonad Haskell 1.4? I liked Haskell 1.4.

   * Peaker: Don't trust the @src, luke

   * dmwit: If it fits in a tweet, you haven't included enough
 information to debug it yet.

Top Reddit Stories

   * The Haskell Cast #3 - Simon Peyton Jones on GHC
 Domain: haskellcast.com, Score: 88, Comments: 11
 On Reddit: [1] http://goo.gl/0sGzlg
 Original: [2] http://goo.gl/wQ4FKi

   * Elm 0.10 released: faster strings, nice colors, bug fixes,
 and searchable documentation
 Domain: elm-lang.org, Score: 74, Comments: 9
 On Reddit: [3] http://goo.gl/HJ2fc7
 Original: [4] http://goo.gl/xFJJMN

   * Procrustean Mathematics by Edward Kmett
 Domain: fpcomplete.com, Score: 71, Comments: 17
 On Reddit: [5] http://goo.gl/AsB0CM
 Original: [6] http://goo.gl/E1iDNM

   * Haskell hurdle: uninteresting world
 Domain: gundersen.net, Score: 68, Comments: 58
 On Reddit: [7] http://goo.gl/W8l3T1
 Original: [8] http://goo.gl/uBVp1f

   * websockets-0.8 released: with browser shell example + bonus section
 on pipes vs. conduit vs. io-streams
 Domain: jaspervdj.be, Score: 65, Comments: 9
 On Reddit: [9] http://goo.gl/0XvXZa
 Original: [10] http://goo.gl/eUDMn1

   * IHaskell: Haskell for Interactive Computing
 Domain: gibiansky.github.io, Score: 61, Comments: 26
 On Reddit: [11] http://goo.gl/ZpNpq8
 Original: [12] http://goo.gl/A8iccI

   * ShellCheck – static analysis and linting tool for sh/bash script
 Domain: shellcheck.net, Score: 55, Comments: 10
 On Reddit: [13] http://goo.gl/z0giaP
 Original: [14] http://goo.gl/zF3DLB

   * Micro-tutorial: liftM by accident
 Domain: self.haskell, Score: 54, Comments: 29
 On Reddit: [15] http://goo.gl/d6ReRs
 Original: [16] http://goo.gl/d6ReRs

   * Barclays are hiring: Haskell developers in London and Kiev
 Domain: self.haskell, Score: 52, Comments: 14
 On Reddit: [17] http://goo.gl/Fq7JPE
 Original: [18] http://goo.gl/Fq7JPE

   * License monads
 Domain: joeyh.name, Score: 52, Comments: 18
 On Reddit: [19] http://goo.gl/oZ9La1
 Original: [20] http://goo.gl/9C1Stp

   * Show Reddit: My weekend project, PureScript
 Domain: functorial.com, Score: 49, Comments: 61
 On Reddit: [21] http://goo.gl/sRx1Eh
 Original: [22] http://goo.gl/TJBCYN

   * Deamortized ST by Edward Kmett
 Domain: fpcomplete.com, Score: 49, Comments: 57
 On Reddit: [23] http://goo.gl/Vck3Ij
 Original: [24] http://goo.gl/wtaueO

   * HaLVM 2.0 Developer's Release (trans: buggy but API-stable
pre-release)
 now available for folks to try. GHC 7.8, threaded RTS, SMP HaLVM
support,
 0-copy networking, and more.
 Domain: community.galois.com, Score: 44, Comments: 13
 On Reddit: [25] http://goo.gl/5Psg7B
 Original: [26] http://goo.gl/xQFUA2

   * Could you explain why complexity of monadic IO is worth it?
 Domain: self.haskell, Score: 43, Comments: 128
 On Reddit: [27] http://goo.gl/esFCc4
 Original: [28] http://goo.gl/esFCc4

   * London Haskell User Group 18/09/2013: Oliver Charles on pipes [video]
 Domain: ocharles.org.uk, Score: 42, Comments: 14
 On Reddit: [29] http://goo.gl/8kDKnw
 Original: [30] http://goo.gl/hi3L3P

   * C-- as a project separate from GHC
 Domain: cminusminus.org, Score: 42, Comments: 14
 On Reddit: [31] http://goo.gl/fvUjIk
 Original: [32] http://goo.gl/VueAA

   * How to start a new Haskell project
 Domain: jabberwocky.eu, Score: 42, Comments: 26
 On Reddit: [33] http://goo.gl/6dRRXn
 Original: [34] http://goo.gl/btWJYS

   * The let-no-escape optimization
 Domain: lambda.jstolarek.com, Score: 41, Comments: 1
 On Reddit: [35] http://goo.gl/l8xhuP
 Original: [36] http://goo.gl/J8uekI

   * Improving Applicative do-notation
 Domain: tmorris.net, Score: 40, Comments: 150
 On Reddit: [37] http://goo.gl/MXoPdz
 Original: [38] http://goo.gl/y1I8Tx

   * Odersky: The Trouble with Types - Strange Loop 2013 [InfoQ]
 Domain: infoq.com, Score: 39, Comments: 55
 On Reddit: [39] http://goo.gl/5QEJfz
 Original: [40] http://goo.gl/Ir4kwG

Top StackOverflow Questions

   * Haskell Thrift library 300x slower than C++ in performance test
 votes: 34, answers: 5
 Read on SO: [41] http://goo.gl/timvYf

   * Creating methods bound to records in Haskell
 votes: 10, answers: 1
 Read on SO: [42] http://goo.gl/4E4Sgh

   * Installing  Building GHC with OSX Mavericks GHC
 votes: 10, answers: 1
 Read on SO: [43] http://goo.gl/44PIaj

   * How to properly communicate compile-time information to
 Template Haskell functions?
 votes: 10, answers: 0
 Read on SO: [44] http://goo.gl/YQkGbl

   * Data.Text vs String

Annotations

Re: Annotations

RE: Annotations

Re: Annotations

Re: love for hpc?

Re: love for hpc?

[Haskell] Haskell Weekly News: Issue 285

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