Ah yes, thank you!
* Francesco Mazzoli [2013-05-08 08:51:12+0100]
> At Wed, 8 May 2013 09:46:08 +0300,
> Roman Cheplyaka wrote:
> >
> > I wonder whether it's always possible to break cycles using GHC's
> > .hs-boot files.
> >
> > Consider the following schematic example:
> >
> > module A whe
At Wed, 8 May 2013 09:46:08 +0300,
Roman Cheplyaka wrote:
>
> I wonder whether it's always possible to break cycles using GHC's
> .hs-boot files.
>
> Consider the following schematic example:
>
> module A where
>
> import B
>
> data A
>
> f :: B -> A
> f = undefined B.g
>
> modul
Hi,
> module A(A) where
> data A
> deriving Show
I think you should use "instance Show A" rather than "deriving Show".
All the boot file needs to do is say that the instance exists, not
explain how it is constructed.
Cheers,
Ganesh
Thanks Roberto!
Roberto Zunino wrote:
Chris Kuklewicz wrote:
There is no way to create a "A.hs-boot" file that has all of
(1) Allows A.hs-boot to be compiled without compiling B.hs first
(2) Allows B.hs (with a {-# SOURCE #-} pragma) to be compiled after
A.hs-boot
(3) Allows A.hs to com
John Meacham <[EMAIL PROTECTED]> wrote:
> Chris Kuklewicz wrote:
> > I have reached an impasse in designing a Haskell API for the
> > google's The messages in protobuf are defined in a namespace
> > that nests in the usual hierarchical OO style that Java
> > encourages.
>
> > To avoid namespace con
On Tue, Jul 15, 2008 at 12:21:16PM +0100, Chris Kuklewicz wrote:
> I have reached an impasse in designing a Haskell API for the google's
> The messages in protobuf are defined in a namespace that nests in the usual
> hierarchical OO style that Java encourages.
>
> To avoid namespace conflicts, I ma
On Wed, Jul 16, 2008 at 12:54 AM, Henning Thielemann
<[EMAIL PROTECTED]> wrote:
> Sooner or later you want generalize your datatypes. Then you can define
> data A b = A b
> and you do not need to import B any longer. I do not know if this is a
> generally applicable approach, but it helped me in
What about generating the verbose accessor/single module code, and
then creating a hierarchical module space as well, all importing your
Base module, and reexporting the data types you want as well as less
verbosely named accessor functions? Of course, this will break record
update syntax,
Chris Kuklewicz wrote:
There is no way to create a "A.hs-boot" file that has all of
(1) Allows A.hs-boot to be compiled without compiling B.hs first
(2) Allows B.hs (with a {-# SOURCE #-} pragma) to be compiled after
A.hs-boot
(3) Allows A.hs to compiled after A.hs-boot with a consistent
On Tue, 15 Jul 2008, Chris Kuklewicz wrote:
Consider these 3 files:
A.hs:
module A(A) where
import B(B)
data A = A B
B.hs
module B(B) where
import A(A)
data B = B A
Main.hs
module Main where
import A
import B
main = return ()
Sooner or later you want generalize your datatypes. Then y
Ah, a teachable moment. One of us is not entirely correct about what GHC can do
with this example. Hopefully I am wrong, but my experiments...
Max Bolingbroke wrote:
And there is no way ghc can compile these in separate modules.
I may be being redundant here, but you may not know that GHC a
> And there is no way ghc can compile these in separate modules.
I may be being redundant here, but you may not know that GHC actually
can compile mutually recursive modules. See
http://www.haskell.org/ghc/docs/latest/html/users_guide/separate-compilation.html#mutual-recursion
. Of course, this is
G'day all.
Quoting Isaac Dupree <[EMAIL PROTECTED]>:
Luckily,
it is very often the case that your code will be better off anyway if
refactored to have less module recursion. (though not always.)
Nonetheless, I prefer not to leave the robustness of my code to luck.
Besides, if I liked structur
Richard Giraud wrote:
Hello
I'm using GHC 6.8.2 with mutally recursive modules. I'm familiar with
how to do simple cases in GHC ({-# SOURCE #-} and .hs-boot files) but I
can't figure out how to get it to work for a particular set of modules.
Is it known (i.e., proven) that GHC 6.8.2 can com
On Mon, Sep 27, 2004 at 10:46:25AM -0700, Fergus Henderson wrote:
> (2) Although most of the mutual recursion occurred only in the
> intermediate stages of the refactoring, some of the mutual
> recursion remained at the end of the refactoring, forcing
> two modules with only the
G'day all.
Quoting Henning Thielemann <[EMAIL PROTECTED]>:
> Why can't GHC and Hugs go this way?
As Alastair noted, the problem is that Haskell allows you to export
symbols from a module whose types are unknown unless you type-check
modules that it imports. Simple example:
module A where
Alastair:
> A crude approach is to assume the type (\forall a. a) for any
> function with no prototype
Andreas:
> Huh? How can that ever be sound?
You're right, it's not - my mistake.
I guess that leaves two options:
1) Insist on a prototype for any exported function.
2) Insist on a prototype
An anecdotal note -
hbcc (the front end to the pH and Eager Haskell compilers, and also of
GRIN) contained several mutually recursive modules both in the compiler
and in the prelude.
One of the best things we ever did was get rid of the mutual recursion.
The resulting refactoring helped us to gr
On Fri, 24 Sep 2004, Malcolm Wallace wrote:
> The main obstacle is that Haskell systems generally process one
> file/module at a time. To extract an interface from each module
> first, before further processing, would not only require a second
> pass over the source files, but to load all of the
Alastair Reid wrote:
Generating .hiboot files by just deleting function definitions fails if there
is no prototype for an exported function. A crude approach is to assume the
type (\forall a. a) for any function with no prototype but, although this is
sound (I think), it will cause valid progra
The original Haskell design included interface files usually with names like
Main.hi
IIRC, Yale Haskell expected them to be hand-written while HBC and GHC
machine-generated but allowed the careful user to write them by hand.
Sometime around Haskell 1.4 or 98, they were dropped because Yale Haske
Henning Thielemann <[EMAIL PROTECTED]> writes:
> >a situation which occurs only very rarely, and for which
> > there is a relatively easy workaround.
>
> Namely? ...
See below.
> It's interesting how other languages solve this problem. In Modula-3 it
> is solved by explicit module
Henning Thielemann <[EMAIL PROTECTED]> writes:
> As far as can see neither Hugs or GHC really support them. Is this still
> on the to-do list or is it almost dropped due to implementation
> difficulties?
Hugs doesn't support mutually-recursive modules at all. Ghc and nhc98
support them only if
On Fri, 24 Sep 2004, Malcolm Wallace wrote:
> Hugs doesn't support mutually-recursive modules at all. Ghc and nhc98
> support them only if you hand-write a .hi-boot file to bootstrap the
> compilation. I would guess that better support from the mainstream
> implementations is unlikely, because
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