Hi all!
Last day I was trying to fix idiii library, because it uses utf8 for parsing
non-unicode content. I found the functions
> -- | Parses one value and returns it as a 'String'
> parseString :: CharEncoding -> TagParser String
> parseString enc = do
> v <- case enc of
> 0x01 -> pars
And swap the arguments.
Thanks for going the extra mile.
Michael
--- On Thu, 2/3/11, Daniel Fischer wrote:
From: Daniel Fischer
Subject: Re: [Haskell-cafe] Reader monad wrapping State monad
To: "michael rice"
Cc: haskell-cafe@haskell.org
Date: Thursday, February 3, 2011, 4
On Thursday 03 February 2011 21:40:13, michael rice wrote:
> Hi Daniel,
>
> Ok, but what I was looking for was ReaderT on top, State on the bottom.
No problem, just change the definition of the Heron type synonym and swap
the applcations of runReader[T] and evalState[T] in mySqrt, the monadic
sq
this case no use of lift at all.
Michael
--- On Thu, 2/3/11, Daniel Fischer wrote:
From: Daniel Fischer
Subject: Re: [Haskell-cafe] Reader monad wrapping State monad
To: haskell-cafe@haskell.org
Cc: "michael rice"
Date: Thursday, February 3, 2011, 2:54 PM
On Thursday 03 Februar
On 3 February 2011 19:18, michael rice wrote:
> but how do I get the constant a from the Reader monad?
>
http://hackage.haskell.org/packages/archive/transformers/latest/doc/html/Control-Monad-Trans-Reader.html#v:ask
You also need to change the type to use ReaderT.
--
Ozgur Akgun
_
On Thursday 03 February 2011 20:18:43, michael rice wrote:
> Given the first program, it seems that the unchanging first element of
> the tuple could be handled by a Reader monad, leading to the second
> program, where b becomes the state, but how do I get the constant a from
> the Reader monad?
Y
Is the idea here merely an exercise in using the state monad? This can be
easily performed using pure code.
Bob
On 3 Feb 2011, at 19:18, michael rice wrote:
> Given the first program, it seems that the unchanging first element of the
> tuple could be handled by a Reader monad, leading to the
Given the first program, it seems that the unchanging first element of the
tuple could be handled by a Reader monad, leading to the second program, where
b becomes the state, but how do I get the constant a from the Reader monad?
Michael
==
import Control.Monad.State
type Gen
2010/12/30 David Leimbach :
>
> Reader Writer State is commonly needed in big applications so transformers
> provides one for us:
> http://hackage.haskell.org/packages/archive/transformers/0.2.2.0/doc/html/Control-Monad-Trans-RWS-Lazy.html
> Pretty cool stuff if you ask me. I often wondered about
On Wed, Dec 29, 2010 at 1:48 PM, Michael Lazarev
wrote:
> 2010/12/29 michael rice
> > I had an "Aha!" moment and it all makes sense now. Just as the State
> monad can hold a generator (which can change) and pass it down a calculation
> chain, a Reader monad can hold an environment (which doesn't
2010/12/29 michael rice
> I had an "Aha!" moment and it all makes sense now. Just as the State monad
> can hold a generator (which can change) and pass it down a calculation chain,
> a Reader monad can hold an environment (which doesn't change) and pass it
> down a calculation chain. I was wond
2010/12/29 Albert Y. C. Lai
> On 10-12-29 12:50 PM, michael rice wrote:
>
>> I think of (r -> m a) as a type signature and Int or Bool by themselves
>> as types. So, all type signatures are themselves types?
>>
>
> http://www.haskell.org/onlinereport/haskell2010/haskellch4.html#x10-620004
>
> In
On 10-12-29 12:50 PM, michael rice wrote:
I think of (r -> m a) as a type signature and Int or Bool by themselves
as types. So, all type signatures are themselves types?
http://www.haskell.org/onlinereport/haskell2010/haskellch4.html#x10-620004
In particular
gendecl → vars :: [context =>] typ
9/10, Daniel Fischer wrote:
From: Daniel Fischer
Subject: Re: [Haskell-cafe] Reader monad
To: haskell-cafe@haskell.org
Cc: "michael rice"
Date: Wednesday, December 29, 2010, 2:47 PM
On Wednesday 29 December 2010 19:30:11, michael rice wrote:
> Yes, I'd already noticed that ReaderT
On Wednesday 29 December 2010 19:30:11, michael rice wrote:
> Yes, I'd already noticed that ReaderT preceded Reader. Guess I'll have
> to check out the Indentity monad too. I hope it's not dependent upon yet
> another monad.
No, the Identity monad stands alone.
And as the name suggests, it's pret
Michael Lazarev
Subject: Re: [Haskell-cafe] Reader monad
To: "michael rice"
Cc: haskell-cafe@haskell.org
Date: Wednesday, December 29, 2010, 12:42 PM
2010/12/29 michael rice
>
> From the docs (and tuts) newtype creates a new type out of an existing type
> and gives
Hi,
Michael Rice wrote:
I think of (r -> m a) as a type signature and Int or Bool by themselves
as types. So, all type signatures are themselves types?
Yes.
In Haskell, functions are first class, so function types like (r -> m a)
are themselves types.
Tillmann
__
I think of (r -> m a) as a type signature and Int or Bool by themselves as
types. So, all type signatures are themselves types?
Michael
--- On Wed, 12/29/10, Henning Thielemann wrote:
From: Henning Thielemann
Subject: Re: [Haskell-cafe] Reader monad
To: "michael rice"
Cc:
2010/12/29 michael rice
>
> From the docs (and tuts) newtype creates a new type out of an existing
type
> and gives a single constructor for doing so.
>
> what is the existing type?
Michael, you may want to see this section:
http://learnyouahaskell.com/functors-applicative-functors-and-monoids#t
On Wed, 29 Dec 2010, michael rice wrote:
In the case of ReaderT and StateT
newtype ReaderT r m a = ReaderT {
-- | The underlying computation, as a function of the environment.
runReaderT :: r -> m a
}
newtype StateT s m a = StateT { runStateT :: s -> m (a, s) }
what is th
?
Michael
--- On Wed, 12/29/10, Ryan Ingram wrote:
From: Ryan Ingram
Subject: Re: [Haskell-cafe] Reader monad
To: "michael rice"
Cc: haskell-cafe@haskell.org
Date: Wednesday, December 29, 2010, 11:11 AM
On Wed, Dec 29, 2010 at 8:06 AM, michael rice wrote:
> Is there an unpara
On Wed, Dec 29, 2010 at 8:06 AM, michael rice wrote:
> Is there an unparameterizable reader monad?
I'm not sure this is the answer you are looking for, but it seems like the
obvious one.
Pick an "r", say "String". Now "Reader String" is an unparameterizable
reader monad that passes around a St
From: Control.Monad.Reader
type Reader r = ReaderT r IdentityThe parameterizable reader monad.
Computations are functions of a shared environment.
The return function ignores the environment, while >>= passes
the inherited environment to both subcomputations
Is there an unparameteri
On Fri, 22 Aug 2008, Alexander Dunlap wrote:
You can always change how you unsafePerformIO the data, though. If you
want to set Planck's constant to 42 (or whatever), just change the
unsafePerformIO $ to unsafePerformIO $ return 42.
you can't change it at runtime
___
On Wed, Aug 20, 2008 at 1:49 AM, Henning Thielemann
<[EMAIL PROTECTED]> wrote:
>
> On Mon, 18 Aug 2008, [EMAIL PROTECTED] wrote:
>
>> G'day all.
>>
>> Quoting Bjorn Buckwalter <[EMAIL PROTECTED]>:
>>
>>> I'd store the constants in a data structure along the lines of:
>>>
data AstroData a = Ast
On Mon, 18 Aug 2008, [EMAIL PROTECTED] wrote:
G'day all.
Quoting Bjorn Buckwalter <[EMAIL PROTECTED]>:
I'd store the constants in a data structure along the lines of:
data AstroData a = AstroData
{ mu_Earth:: GravitationalParameter a
, leapSeconds :: LeapSecondTable
}
I would like
G'day all.
Quoting "Richard A. O'Keefe" <[EMAIL PROTECTED]>:
Just an idiot-level question: so these "constants" are subject
to revision, but *how often*?
Good question. For leap seconds:
- The data can change no quicker than once every 6 months.
- The shortest time between changes was 6 m
Just an idiot-level question: so these "constants" are subject
to revision, but *how often*? What is the actual cost of
recompiling and using them *as* constants, compared with the
cost of rereading the stuff every time you run the program and
passing it around?
--
If stupidity were a crime, who
G'day all.
Quoting Bjorn Buckwalter <[EMAIL PROTECTED]>:
I'd store the constants in a data structure along the lines of:
data AstroData a = AstroData
{ mu_Earth:: GravitationalParameter a
, leapSeconds :: LeapSecondTable
}
I would like to know if there is any consensus on what is
On 2008 Aug 18, at 17:09, Evan Laforge wrote:
They also seem to be removed from ghc:
http://www.haskell.org/pipermail/cvs-ghc/2006-September/031824.html
Again, that's *linear* implicit parameters (%foo instead of ?foo).
Oh, you're right. I made exactly the same mistake you made, and righ
>> They also seem to be removed from ghc:
>>
>> http://www.haskell.org/pipermail/cvs-ghc/2006-September/031824.html
>
>
> Again, that's *linear* implicit parameters (%foo instead of ?foo).
Oh, you're right. I made exactly the same mistake you made, and right
after you warned against making it too
On 2008 Aug 18, at 16:20, Evan Laforge wrote:
Which is comparable to the Reader version (with the
advantage/disadvantage of the body of 'escapeVelocity' not being
monadic).
In my opinion the implicit parameters don't make things simpler,
only less
portable, that's why I prefer the Reader mon
>> Which is comparable to the Reader version (with the
>> advantage/disadvantage of the body of 'escapeVelocity' not being
>> monadic).
>
> In my opinion the implicit parameters don't make things simpler, only less
> portable, that's why I prefer the Reader monad.
They also seem to be removed from
Bjorn Buckwalter schrieb:
On Mon, Aug 18, 2008 at 2:02 PM, Henning Thielemann
<[EMAIL PROTECTED]> wrote:
>>
Instead of
muEarth :: GravitationalParameter a
muEarth = ???
escapeVelocity :: a
escapeVelocity = ... muEarth ...
you would write
data AstroData a = AstroData
{ muEarth ::
On Mon, Aug 18, 2008 at 2:02 PM, Henning Thielemann
<[EMAIL PROTECTED]> wrote:
>
> On Mon, 18 Aug 2008, Bjorn Buckwalter wrote:
>
>> On Mon, Aug 18, 2008 at 11:16 AM, Henning Thielemann
>> <[EMAIL PROTECTED]> wrote:
>>>
>>> On Mon, 18 Aug 2008, Bjorn Buckwalter wrote:
>>>
I would like to know
On Mon, 18 Aug 2008, Bjorn Buckwalter wrote:
On Mon, Aug 18, 2008 at 11:16 AM, Henning Thielemann
<[EMAIL PROTECTED]> wrote:
On Mon, 18 Aug 2008, Bjorn Buckwalter wrote:
I would like to know if there is any consensus on what is the best way
to make such a data structure accessible in pure f
On Mon, 18 Aug 2008, Brandon S. Allbery KF8NH wrote:
On 2008 Aug 18, at 11:16, Henning Thielemann wrote:
know implicit parameters break referential transparency.
http://www.haskell.org/haskellwiki/The_Monad.Reader/Issue2/FunWithLinearImplicitParameters
Are you making the same mistake I did?
On 2008 Aug 18, at 11:16, Henning Thielemann wrote:
know implicit parameters break referential transparency.
http://www.haskell.org/haskellwiki/The_Monad.Reader/Issue2/FunWithLinearImplicitParameters
Are you making the same mistake I did? Linear implicit parameters are
different from impli
On 2008 Aug 18, at 10:59, Bjorn Buckwalter wrote:
I would like to know if there is any consensus on what is the best way
to make such a data structure accessible in pure functions. Passing it
explicitly would be a mess. It seems that two options are to use
either a Reader monad or implicit parame
On Mon, Aug 18, 2008 at 11:16 AM, Henning Thielemann
<[EMAIL PROTECTED]> wrote:
>
> On Mon, 18 Aug 2008, Bjorn Buckwalter wrote:
>
>> I would like to know if there is any consensus on what is the best way
>> to make such a data structure accessible in pure functions. Passing it
>> explicitly would
On Mon, 18 Aug 2008, Bjorn Buckwalter wrote:
I would like to know if there is any consensus on what is the best way
to make such a data structure accessible in pure functions. Passing it
explicitly would be a mess. It seems that two options are to use
either a Reader monad or implicit parameter
All,
I have a growing amount of astrodynamics code that relies on various
physical "constants". The problem with these so called "constants" are
that they either aren't really constants or aren't well known. An
example is the leap second table (see Data.Time.Clock.TAI). I'd like
to be able to fetc
All,
I have a growing amount of astrodynamics code that relies on various
physical "constants". The problem with these so called "constants" are
that they either aren't really constants or aren't well known. An
example is the leap second table (see Data.Time.Clock.TAI). I'd like
to be able to fetc
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