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GHC modding Qs
Hello, Haskell is one of my favorite programming languages syntactically (and feature wise) but I've always wanted a variant/derivative of Haskell where some of the default semantics are the opposite way around such as:
- Strict by default.
- All types are unboxed types by default and record aggregation is like in C/C++, all values of these types are allocated on the stack.
- (GC) Heap allocation is more explicit via pointer types.
I'm a full-time programmer so I don't have time alone to start such a huge project from scratch. So I was thinking about making a fork of GHC and incrementally swapping some of the default semantics.
What would be the feasibility/difficulty of such changes?
submitted by snk_kid[link] [75 comments]
Categories: Incoming News
question about type constructors
Hi,
In the program I am trying to write, I have a problem that can be reduced to
the following dummy example:
--------------------------
{-# LANGUAGE GADTs #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE IncoherentInstances #-}
class PrettyPrint a where
prettify :: a -> String
data Gender = Male | Female | Gender3 | Gender4
data Person :: Gender -> * where
Person :: String -> Person b
Child :: String -> Person a -> Person b -> Person c
instance PrettyPrint (Person a)
instance PrettyPrint (Person Male) where
prettify (Person name) = "My name is " ++ (show name)
++ " and I am a male"
prettify (Child name person1 person2) = "My name is " ++ (show name)
++ " and my parents are:" ++ (prettify person1) ++ ", "
++ (prettify person2)
main = do
let p1 = Person "Jim" :: Person Male
let p2 = Person "Joe" :: Person Male
let p3 = Child "Jack" p1 p2
print $ prettify p1
print $ prettify p2
print $ pre
Categories: Offsite Discussion
Debugging embedded ruby interpreter
Hello,
I am trying to embed a ruby interpreter into my Haskell library. It
didn't seem complicated, and went flawlessly until I tried using it a
lot. Then I got segfaults.
Here is a test program that corrupts the Array object that is being
created :
https://github.com/bartavelle/hruby/blob/271d99e26a5df075b1011e4b30adf6adddd1c8d2/test/roundtrip.hs
Changing line 46 to this makes it work:
v <- pick (listOf arbitrary :: Gen [Double])
And this version makes it fail again :
v <- pick (listOf subvalue :: Gen [Value])
As you can see, the "frequencies" of "subvalue" are set so that only
JSON Values representing Doubles are generated. As the toRuby and
fromRuby instances for Value are just pure wrappers over the instances
for Double, the non-pure code that is executed should be the same. Am I
wrong here ?
Given that there is almost no documentation for doing this Ruby
embedding, I am unsure that I am doing it right. I looked at the Hubris
code and several other sources on the Internet, but can't find what i
Categories: Offsite Discussion
Votes for generalizing mapM &c.
Here are the current totals by my count, ignoring any 0s:
+13 / -0
+1 / -11
+0 / -12
+0 / -13
- C.
Categories: Offsite Discussion
SLE 2013 - Final Call for Papers
========================================================================
CALL FOR PAPERS
6th International Conference on Software Language Engineering (SLE 2013)
Oct 26-28, 2013, Indianapolis, IN, USA
(Co-located with SPLASH 2013 and GPCE 2013)
General chair:
Eric Van Wyk, University of Minnesota, USA
Program co-chairs:
Martin Erwig, Oregon State University, USA
Richard Paige, University of York, UK
Keynote speaker:
Don Batory, University of Austin, USA
http://planet-sl.org/sle2013
========================================================================
IMPORTANT DATES
Deadline for abstracts: June 7, 2013 (Midnight UTC-8, Pacific Standard Time)
Deadline for full papers: June 14, 2013 (Midnight UTC-8, Pacific Standard Time)
Notification to authors: August 3, 2013
Camera-ready copies due: August 16, 2013
Conference: October 26 -28, 2013
TYPES OF SUBMISSIONS
We solicit the following types of papers:
- Research papers: These should report a substantial research contribution
Categories: Incoming News
"Haskell from N00b to Real World Programmer"
Hello,
As hinted in the previous HCAR, this year we will organize an workshop
entitled like the subject of this mail[1].
It will be organized by ROSEdu (Romanian Open Source Education) [2]
and the newly founded Haskell-Romania group (no link yet, working on
that). It is one workshop in a series of summer workshops organized by
ROSEdu (go one level up in the wiki, some of them are in Romanian and
I don't want to blindly give links to Romanian pages).
The entire schedule is given on the wiki page at [1] and detailed below:
Day 1 (8th of July)
Introduction. History and Syntax. -- basic introduction to the
language. Including < at >lambdabot usage as an example
Programming with Static Typing as An Ally. -- designing with types and
using GHCI for rapid prototyping and testing type of expressions.
Possible to include < at >djinn
Programming with State and Style. -- gentle introduction to monads in
the style of "You could have invented monads" [3]
Day 2 (9th of July)
Packaging and Distributing Code. -- hackage, cabal,
Categories: Offsite Discussion
accessing a type variable in instance declaration
Hi all,
I wonder if there is some means to get a type variable value in the body of
a class instance definition. It seems it is not possible (a workaround has
already been given on this list), but I would like a confirmation.
For example, imagine that I have a Tensor type constructor, that takes a
type-level integer (representing the Tensor order) to make a concrete type:
---------
instance Show (Tensor order) where
show TensorVar str = show "tensor " ++ str ++ " of order "
++ (show (c2num order))
----------
where c2num transforms a type-level integer to an integer, through
typeclasses (see
http://www.haskell.org/haskellwiki/The_Monad.Reader/Issue5/Number_Param_Types)
I obtain a compilation error: order is not known in the body of the
instance. Putting ScopedTypeVariable as extension does not change anything
(http://www.haskell.org/ghc/docs/7.0-latest/html/users_guide/other-type-extensions.html#scoped-type-variables).
I have tried also using forall, withou
Categories: Offsite Discussion
I'm breaking into haskell with a fury and a little bit of frustration...
I'm trying to write a program to turn 13432 into the list: [10000,3000,400,30,2]
and I have the following code:
numbefier :: Int -> [Int] numbefier base 0 = [] numbefier number base= show( (highestd number) * (digitv number base)) : numbefier(newnum number) highestd number = (div number (10^(length(show number) - 1))) digitv number base = (base^(length(show number) - 1)) newnum number = (mod number (10^(length(show number) - 1 )))when I try to load the program into ghci it complains at me:
Couldn't match type `Int' with `[Char]' Expected type: [String] Actual type: [Int] In the return type of a call of `numbefier' In the second argument of `(:)', namely `(numbefier (newnum number))' In the expression: (show ((highestd number) * (digitv number base))) : (numbefier (newnum number)) Failed, modules loaded: none.any ideas?
EDIT: Y'all are so helpful. I'm going to try reading a book on haskell before I re-attempt this problem.
submitted by runnerboy[link] [22 comments]
Categories: Incoming News
Haskell in Production [slides]
Categories: Incoming News
On the history of the question of whether natural language is “illogical”
A nice essay from Barbara Partee on the origins of formal semantics of natural languages and Montague Grammar.
Not directly programming language material, the topic is likely to interest many here. I think several interesting previous discussions related to Montague can be found by searching the archives.
Categories: Offsite Discussion
www.glc.us.es
Categories: Offsite Blogs
Beginner question: how are list comprehensions considered functional?
For example:
ls n = [ x | x <- [1..n] ]In this list comprehension, isn't x taking different values from 1 to n? Isn't that exactly what functional programming stays away from? I'm sure my reasoning is wrong somewhere, so please let me know.
On another note, I'd be really interested to know more about Haskell theory, and why things were made the way they are. Any resources?
Edit: Thank you /r/haskell! You've been really helpful.
submitted by Alpha_Q[link] [34 comments]
Categories: Incoming News
www.glc.us.es
Categories: Offsite Blogs
Numeric.GSL.Integration
Categories: Offsite Blogs
gitit demo - Gitit
Categories: Offsite Blogs
Announce: vsim the VHDL-subset simulator(unmaintained)
Hi. I'd like to announce the vsim - the simulator for (small subset
of) VHDL language. Currently
the project contains pretty large Java part and is not maintained.
That's why I don't want to
publish it on Hackage. Still, as far as I now have a permission to
share the code, I would like to do it.
https://github.com/grrwlf/vsim
VSim is a VHDL simulator project aimed develop a methods of compiling VHDL code
into a high-level language (Haskell). Currently it is able to compile simple
VHDL programs, containing plain integer types, 1-dimentional arrays, records. It
supports processes, procedures, functions (partly). Breakpoints and wait
statements should work.
Simulator compile VHDL into Haskell in several steps.
Firstly, VHDL is translated into VIR-file by a translator written in Java (see
tr/ folder and runtr function in ./simenv shell script). VIR file is lisp-like
file, describing vhdl entities in a less complex manner. For example, it
contains all the port maps expanded.
Secondly, VSim tool is used to tr
Categories: Offsite Discussion
HP 2013.2 - RC3 installers for OS X
The Mac OS X RC3 installers are up:
Haskell Platform 2013.2.0.0 32bit
rc3.signed.pkg<http://www.ozonehouse.com/mark/platform/Haskell%20Platform%202013.2.0.0%2032bit%20rc3.signed.pkg>
Haskell Platform 2013.2.0.0 64bit
rc3.signed.pkg<http://www.ozonehouse.com/mark/platform/Haskell%20Platform%202013.2.0.0%2064bit%20rc3.signed.pkg>
Only difference in these from RC2 is that the missing documentation for
network, random, and primitive has been restored.
These will be the final, barring any catastrophic issue.
— Mark
15dd8762c9800308cb7cfdd16ea1a8e74988e06a Haskell Platform 2013.2.0.0 32bit
rc3.signed.pkg
89e6fb747816af69acabc5c04cee103257855614 Haskell Platform 2013.2.0.0 64bit
rc3.signed.pkg
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Categories: Offsite Discussion