From KSergej at seznam.cz  Thu Jun  6 19:06:00 2019
From: KSergej at seznam.cz (Sergej KAREL)
Date: Thu, 06 Jun 2019 21:06:00 +0200 (CEST)
Subject: [Haskell-beginners] How can I view a digit on the N-th position of
	9^(9^9) in Haskell?
Message-ID: <55T.EThB.72{hdq8EsVi.1S{MGO@seznam.cz>

Hello,
Im looking for setting up a solver for the determination of digit on N-th 
position of the high value number


Best regards

Sergej
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From fa-ml at ariis.it  Thu Jun  6 20:12:56 2019
From: fa-ml at ariis.it (Francesco Ariis)
Date: Thu, 6 Jun 2019 22:12:56 +0200
Subject: [Haskell-beginners] How can I view a digit on the N-th position
 of 9^(9^9) in Haskell?
In-Reply-To: <55T.EThB.72{hdq8EsVi.1S{MGO@seznam.cz>
References: <55T.EThB.72{hdq8EsVi.1S{MGO@seznam.cz>
Message-ID: <20190606201256.os2ezycnh4qtm64c@x60s.casa>

Hello Sergej,

On Thu, Jun 06, 2019 at 09:06:00PM +0200, Sergej KAREL wrote:
> Hello,
> Im looking for setting up a solver for the determination of digit on N-th 
> position of the high value number

The trick is to only take the appropriate reminder instead of the whole
multiplication result. Something like:

    λ> myMult x y = rem (x * y) 100
    λ> :t +d foldr1
    foldr1 :: (a -> a -> a) -> [a] -> a
    λ> myPower x y = foldr1 myMult (replicate y x)
    λ> myPower 9 9
    89
    λ> 9^9
    387420489
    λ> myPower 9 (myPower 9 9)
    89

Does this help?
-F

From KSergej at seznam.cz  Fri Jun  7 04:06:27 2019
From: KSergej at seznam.cz (Sergej KAREL)
Date: Fri, 07 Jun 2019 06:06:27 +0200 (CEST)
Subject: [Haskell-beginners]
	=?utf-8?q?How_can_I_view_a_digit_on_the_N-th_?=
	=?utf-8?q?position_of_9=5E=289=5E9=29_in_Haskell=3F?=
References: <55T.EThB.72{hdq8EsVi.1S{MGO@seznam.cz>
 <20190606201256.os2ezycnh4qtm64c@x60s.casa>
Message-ID: <ZqG.EThQ.2hrfaW{DLFy.1S{UB3@seznam.cz>

Hello Francesco,
Im total beginner. I read some books and online pages.

I do not know, how to apply your rows if Im looking eg. digit on position 
177486336 of the number string

Sorry for asking so straightforward

Sergej





---------- Původní e-mail ----------
Od: Francesco Ariis <fa-ml at ariis.it>
Komu: beginners at haskell.org
Datum: 6. 6. 2019 22:13:36
Předmět: Re: [Haskell-beginners] How can I view a digit on the N-th position
of 9^(9^9) in Haskell? 
"Hello Sergej,

On Thu, Jun 06, 2019 at 09:06:00PM +0200, Sergej KAREL wrote:
> Hello,
> Im looking for setting up a solver for the determination of digit on N-th 
> position of the high value number

The trick is to only take the appropriate reminder instead of the whole
multiplication result. Something like:

λ> myMult x y = rem (x * y) 100
λ> :t +d foldr1
foldr1 :: (a -> a -> a) -> [a] -> a
λ> myPower x y = foldr1 myMult (replicate y x)
λ> myPower 9 9
89
λ> 9^9
387420489
λ> myPower 9 (myPower 9 9)
89

Does this help?
-F
_______________________________________________
Beginners mailing list
Beginners at haskell.org
http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
"
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From michael at orlitzky.com  Fri Jun  7 14:52:50 2019
From: michael at orlitzky.com (Michael Orlitzky)
Date: Fri, 7 Jun 2019 10:52:50 -0400
Subject: [Haskell-beginners] How can I view a digit on the N-th position
 of 9^(9^9) in Haskell?
In-Reply-To: <ZqG.EThQ.2hrfaW{DLFy.1S{UB3@seznam.cz>
References: <55T.EThB.72{hdq8EsVi.1S{MGO@seznam.cz>
 <20190606201256.os2ezycnh4qtm64c@x60s.casa>
 <ZqG.EThQ.2hrfaW{DLFy.1S{UB3@seznam.cz>
Message-ID: <074b7349-665a-bd0d-2fdd-054226060221@orlitzky.com>

On 6/7/19 12:06 AM, Sergej KAREL wrote:
> Hello Francesco,
> Im total beginner. I read some books and online pages.
> I do not know, how to apply your rows if Im looking eg. digit on
> position *177486336 *of the number string
> Sorry for asking so straightforward
> Sergej

This is a math problem. Read the first few chapters of a book on number
theory -- you'll usually find something like this in the exercises.

For example, exercise 2.30 in the freely-available "Elementary Number
Theory: Primes, Congruences, and Secrets" by William Stein:

  https://wstein.org/ent/


From utprimum at gmail.com  Fri Jun  7 16:21:39 2019
From: utprimum at gmail.com (Ut Primum)
Date: Fri, 7 Jun 2019 18:21:39 +0200
Subject: [Haskell-beginners] How can I view a digit on the N-th position
 of 9^(9^9) in Haskell?
In-Reply-To: <074b7349-665a-bd0d-2fdd-054226060221@orlitzky.com>
References: <55T.EThB.72{hdq8EsVi.1S{MGO@seznam.cz>
 <20190606201256.os2ezycnh4qtm64c@x60s.casa>
 <ZqG.EThQ.2hrfaW{DLFy.1S{UB3@seznam.cz>
 <074b7349-665a-bd0d-2fdd-054226060221@orlitzky.com>
Message-ID: <CANjDmKJPfj+oWzC68JY3nbDSCLMtUN8ATSOFZ3x4nNAtwq7N-w@mail.gmail.com>

Hello Sergej,

if you need to know the  Nth digit of a number (i.e. 10987654321), assuming
that we say that the rightmost digit is the digit 1, (so in my example 1st
digit is 1), you can use:
> x=10987654321
> div (mod x (10^N)) (10^(N-1))

So, *if you don't need a fast program* and you want to compute the digit in
position 177486336 of 9^(9^9):
> x=9^(9^9)
> div (mod x (10^177486336)) (10^177486335)
(it takes about 1 minute to compute it)

or in general if you want to know the N-th digit :
> x=9^(9^9)
> div (mod x (10^N)) (10^(N-1))

<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
Mail
priva di virus. www.avg.com
<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

Il giorno ven 7 giu 2019 alle ore 16:53 Michael Orlitzky <
michael at orlitzky.com> ha scritto:

> On 6/7/19 12:06 AM, Sergej KAREL wrote:
> > Hello Francesco,
> > Im total beginner. I read some books and online pages.
> > I do not know, how to apply your rows if Im looking eg. digit on
> > position *177486336 *of the number string
> > Sorry for asking so straightforward
> > Sergej
>
> This is a math problem. Read the first few chapters of a book on number
> theory -- you'll usually find something like this in the exercises.
>
> For example, exercise 2.30 in the freely-available "Elementary Number
> Theory: Primes, Congruences, and Secrets" by William Stein:
>
>   https://wstein.org/ent/
>
> _______________________________________________
> Beginners mailing list
> Beginners at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>
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From hilco.wijbenga at gmail.com  Tue Jun 11 03:44:30 2019
From: hilco.wijbenga at gmail.com (Hilco Wijbenga)
Date: Mon, 10 Jun 2019 20:44:30 -0700
Subject: [Haskell-beginners] How to test "error"?
Message-ID: <CAE1pOi3bKP3KmOZteQMGYmkfx1o=Awdqjyq17yw-sLYZkKE+vw@mail.gmail.com>

Hi all,

I have a function that may call "error" if the input represents a bug
in my program. (Think something like PositiveInt -1; this should never
happen so Maybe or Either are not applicable.)

f :: Whatever
f = error "This should never happen."

spec :: Spec
spec =
    describe "f" $
        it "error" $
            return f `shouldThrow` anyErrorCall

The above does not work, I get "did not get expected exception:
ErrorCall". Using "anyException" doesn't work either.

How can I write a test for this? And (assuming I can get the test to
work), how do I check that the error message is indeed what I expect?

Cheers,
Hilco

From michele.alzetta at gmail.com  Tue Jun 11 07:43:53 2019
From: michele.alzetta at gmail.com (Michele Alzetta)
Date: Tue, 11 Jun 2019 09:43:53 +0200
Subject: [Haskell-beginners] How to test "error"?
In-Reply-To: <CAE1pOi3bKP3KmOZteQMGYmkfx1o=Awdqjyq17yw-sLYZkKE+vw@mail.gmail.com>
References: <CAE1pOi3bKP3KmOZteQMGYmkfx1o=Awdqjyq17yw-sLYZkKE+vw@mail.gmail.com>
Message-ID: <CANhs-xCpDWcAmRVorfQwaJq=xmqBrOJNpJ-DWm4UB_4sQk1QhA@mail.gmail.com>

As beginner to beginner, so take this with a kg of salt  ... isn't what
you're looking for a construction of the Either sort?

That way you get Right and Left and you can check for Left.





Il giorno mar 11 giu 2019 alle ore 05:45 Hilco Wijbenga <
hilco.wijbenga at gmail.com> ha scritto:

> Hi all,
>
> I have a function that may call "error" if the input represents a bug
> in my program. (Think something like PositiveInt -1; this should never
> happen so Maybe or Either are not applicable.)
>
> f :: Whatever
> f = error "This should never happen."
>
> spec :: Spec
> spec =
>     describe "f" $
>         it "error" $
>             return f `shouldThrow` anyErrorCall
>
> The above does not work, I get "did not get expected exception:
> ErrorCall". Using "anyException" doesn't work either.
>
> How can I write a test for this? And (assuming I can get the test to
> work), how do I check that the error message is indeed what I expect?
>
> Cheers,
> Hilco
> _______________________________________________
> Beginners mailing list
> Beginners at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>
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From fa-ml at ariis.it  Tue Jun 11 09:39:09 2019
From: fa-ml at ariis.it (Francesco Ariis)
Date: Tue, 11 Jun 2019 11:39:09 +0200
Subject: [Haskell-beginners] How to test "error"?
In-Reply-To: <CAE1pOi3bKP3KmOZteQMGYmkfx1o=Awdqjyq17yw-sLYZkKE+vw@mail.gmail.com>
References: <CAE1pOi3bKP3KmOZteQMGYmkfx1o=Awdqjyq17yw-sLYZkKE+vw@mail.gmail.com>
Message-ID: <20190611093909.zbbu6ynnjkoxclbt@x60s.casa>

Hello Hilco,

On Mon, Jun 10, 2019 at 08:44:30PM -0700, Hilco Wijbenga wrote:
> f :: Whatever
> f = error "This should never happen."
> 
> spec :: Spec
> spec =
>     describe "f" $
>         it "error" $
>             return f `shouldThrow` anyErrorCall

    import qualified Control.Exception as E

and

    E.evaluate tt' f `shouldThrow` anyErrorCall

should work. Does this work?
-F

From hilco.wijbenga at gmail.com  Wed Jun 12 05:24:09 2019
From: hilco.wijbenga at gmail.com (Hilco Wijbenga)
Date: Tue, 11 Jun 2019 22:24:09 -0700
Subject: [Haskell-beginners] How to test "error"?
In-Reply-To: <CANhs-xCpDWcAmRVorfQwaJq=xmqBrOJNpJ-DWm4UB_4sQk1QhA@mail.gmail.com>
References: <CAE1pOi3bKP3KmOZteQMGYmkfx1o=Awdqjyq17yw-sLYZkKE+vw@mail.gmail.com>
 <CANhs-xCpDWcAmRVorfQwaJq=xmqBrOJNpJ-DWm4UB_4sQk1QhA@mail.gmail.com>
Message-ID: <CAE1pOi0FmirpSYmgbUYO_4GuvxENXA+NG7M=T+JHvmi6XbT2RA@mail.gmail.com>

No, I don't think you should use Either/Maybe to anticipate bugs. If
your code could _legitimately_ fail (it's just something that follows
from your domain) then Maybe/Either are appropriate. Otherwise, some
sort of exception or "error" is more appropriate. E.g., if your domain
knowledge tells you that zeroes are impossible then you would not want
every division to return a Maybe just because division by zero is not
defined. _Because that should never happen._

On Tue, Jun 11, 2019 at 12:44 AM Michele Alzetta
<michele.alzetta at gmail.com> wrote:
>
> As beginner to beginner, so take this with a kg of salt  ... isn't what you're looking for a construction of the Either sort?
>
> That way you get Right and Left and you can check for Left.
>
>
>
>
>
> Il giorno mar 11 giu 2019 alle ore 05:45 Hilco Wijbenga <hilco.wijbenga at gmail.com> ha scritto:
>>
>> Hi all,
>>
>> I have a function that may call "error" if the input represents a bug
>> in my program. (Think something like PositiveInt -1; this should never
>> happen so Maybe or Either are not applicable.)
>>
>> f :: Whatever
>> f = error "This should never happen."
>>
>> spec :: Spec
>> spec =
>>     describe "f" $
>>         it "error" $
>>             return f `shouldThrow` anyErrorCall
>>
>> The above does not work, I get "did not get expected exception:
>> ErrorCall". Using "anyException" doesn't work either.
>>
>> How can I write a test for this? And (assuming I can get the test to
>> work), how do I check that the error message is indeed what I expect?
>>
>> Cheers,
>> Hilco
>> _______________________________________________
>> Beginners mailing list
>> Beginners at haskell.org
>> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners
>
> _______________________________________________
> Beginners mailing list
> Beginners at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

From hilco.wijbenga at gmail.com  Wed Jun 12 05:26:03 2019
From: hilco.wijbenga at gmail.com (Hilco Wijbenga)
Date: Tue, 11 Jun 2019 22:26:03 -0700
Subject: [Haskell-beginners] How to test "error"?
In-Reply-To: <20190611093909.zbbu6ynnjkoxclbt@x60s.casa>
References: <CAE1pOi3bKP3KmOZteQMGYmkfx1o=Awdqjyq17yw-sLYZkKE+vw@mail.gmail.com>
 <20190611093909.zbbu6ynnjkoxclbt@x60s.casa>
Message-ID: <CAE1pOi3iTvaApOS6yr_6=OBn50-T3hMdF51aMfzVRv9y_65XnQ@mail.gmail.com>

Yes, "evaluate" does the trick. Thank you.

On Tue, Jun 11, 2019 at 2:39 AM Francesco Ariis <fa-ml at ariis.it> wrote:
>
> Hello Hilco,
>
> On Mon, Jun 10, 2019 at 08:44:30PM -0700, Hilco Wijbenga wrote:
> > f :: Whatever
> > f = error "This should never happen."
> >
> > spec :: Spec
> > spec =
> >     describe "f" $
> >         it "error" $
> >             return f `shouldThrow` anyErrorCall
>
>     import qualified Control.Exception as E
>
> and
>
>     E.evaluate tt' f `shouldThrow` anyErrorCall
>
> should work. Does this work?
> -F
> _______________________________________________
> Beginners mailing list
> Beginners at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

From frederic-emmanuel.picca at synchrotron-soleil.fr  Fri Jun 21 08:05:21 2019
From: frederic-emmanuel.picca at synchrotron-soleil.fr (PICCA Frederic-Emmanuel)
Date: Fri, 21 Jun 2019 08:05:21 +0000
Subject: [Haskell-beginners] Parser using the show method
Message-ID: <A2A20EC3B8560D408356CAC2FC148E53015BBBC785@SUN-DAG3.synchrotron-soleil.fr>

Hello,

I have a data type like this

data SpaceGroup = P1 | P2 | P21 | C2 | P222 | P2221 | P21212 | P212121 | C222 | C2221 | F222 | I222 | I212121 | P4 | P41 | P42 | P43 | P422 | P4212 | P4122 | P41212 | P4222 | P42212 | P4322 | P43212 | I4 | I41 | I422 | I4122 | P3 | P31 | P32 | P312 | P321 | P3112 | P3121 | P3212 | P3221 | P6 | P61 | P62 | P63 | P64 | P65 | P622 | P6122 | P6522 | P6222 | P6422 | P6322 | R3 | R32 | P23 | P213 | P432 | P4232 | P4332 | P4132 | F23 | F432 | F4132 | I23 | I213 | I432 | I4132
    deriving (Show)

has you can see it is quite long.

I want to write a method in order to parser a string using the show method.

myparser :: Parser SpaceGroup
myparser = do
    ...

I do not want to write for each constructor something like

do
   t <- takeText
   if t == "P21" then P21 else ...

thanks for your help

Frederic

From to_br at uni-bremen.de  Fri Jun 21 12:02:02 2019
From: to_br at uni-bremen.de (Tobias Brandt)
Date: Fri, 21 Jun 2019 14:02:02 +0200
Subject: [Haskell-beginners] Parser using the show method
In-Reply-To: <A2A20EC3B8560D408356CAC2FC148E53015BBBC785@SUN-DAG3.synchrotron-soleil.fr>
References: <A2A20EC3B8560D408356CAC2FC148E53015BBBC785@SUN-DAG3.synchrotron-soleil.fr>
Message-ID: <7e877a3b-aa8f-5259-4819-f829824dc929@uni-bremen.de>

Hello,

you may derive an Enum instance for your SpaceGroup type and then 
generate all enumerations:

data SpaceGroup = P1 | P2 | P21 | C2 | P222 | P2221 | P21212 | P212121 | 
C222 | C2221 | F222 | I222 | I212121 | P4 | P41 | P42 | P43 | P422 | 
P4212 | P4122 | P41212 | P4222 | P42212 | P4322 | P43212 | I4 | I41 | 
I422 | I4122 | P3 | P31 | P32 | P312 | P321 | P3112 | P3121 | P3212 | 
P3221 | P6 | P61 | P62 | P63 | P64 | P65 | P622 | P6122 | P6522 | P6222 
| P6422 | P6322 | R3 | R32 | P23 | P213 | P432 | P4232 | P4332 | P4132 | 
F23 | F432 | F4132 | I23 | I213 | I432 | I4132
     deriving (Show, Enum)


matches t =  t `elem` map show [P1 .. I4132]

But of course this should not be as efficient as writing every 
constructor case by hand.


Tobias



On 6/21/19 10:05 AM, PICCA Frederic-Emmanuel wrote:
> Hello,
>
> I have a data type like this
>
> data SpaceGroup = P1 | P2 | P21 | C2 | P222 | P2221 | P21212 | P212121 | C222 | C2221 | F222 | I222 | I212121 | P4 | P41 | P42 | P43 | P422 | P4212 | P4122 | P41212 | P4222 | P42212 | P4322 | P43212 | I4 | I41 | I422 | I4122 | P3 | P31 | P32 | P312 | P321 | P3112 | P3121 | P3212 | P3221 | P6 | P61 | P62 | P63 | P64 | P65 | P622 | P6122 | P6522 | P6222 | P6422 | P6322 | R3 | R32 | P23 | P213 | P432 | P4232 | P4332 | P4132 | F23 | F432 | F4132 | I23 | I213 | I432 | I4132
>      deriving (Show)
>
> has you can see it is quite long.
>
> I want to write a method in order to parser a string using the show method.
>
> myparser :: Parser SpaceGroup
> myparser = do
>      ...
>
> I do not want to write for each constructor something like
>
> do
>     t <- takeText
>     if t == "P21" then P21 else ...
>
> thanks for your help
>
> Frederic
> _______________________________________________
> Beginners mailing list
> Beginners at haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/beginners

From fa-ml at ariis.it  Fri Jun 21 12:09:36 2019
From: fa-ml at ariis.it (Francesco Ariis)
Date: Fri, 21 Jun 2019 14:09:36 +0200
Subject: [Haskell-beginners] Parser using the show method
In-Reply-To: <A2A20EC3B8560D408356CAC2FC148E53015BBBC785@SUN-DAG3.synchrotron-soleil.fr>
References: <A2A20EC3B8560D408356CAC2FC148E53015BBBC785@SUN-DAG3.synchrotron-soleil.fr>
Message-ID: <20190621120936.lmmpldlwupb3xbkm@x60s.casa>

Hello Frederic,

On Fri, Jun 21, 2019 at 08:05:21AM +0000, PICCA Frederic-Emmanuel wrote:
> Hello,
> 
> I have a data type like this
> 
> data SpaceGroup = P1 | P2 | P21 | C2 | P222 | P2221 | P21212 | P212121 | C222 | C2221 | F222 | I222 | I212121 | P4 | P41 | P42 | P43 | P422 | P4212 | P4122 | P41212 | P4222 | P42212 | P4322 | P43212 | I4 | I41 | I422 | I4122 | P3 | P31 | P32 | P312 | P321 | P3112 | P3121 | P3212 | P3221 | P6 | P61 | P62 | P63 | P64 | P65 | P622 | P6122 | P6522 | P6222 | P6422 | P6322 | R3 | R32 | P23 | P213 | P432 | P4232 | P4332 | P4132 | F23 | F432 | F4132 | I23 | I213 | I432 | I4132
>     deriving (Show)
> 
> has you can see it is quite long.
> 
> I want to write a method in order to parser a string using the show method.

If you can use `read`

    data SpaceGroup = P1 | P2 | P21 | C2 | P222
                    deriving (Show, Read)

    p = read <$> takeText

and if you cannot

    import Text.Parsec
    import Text.Parsec.String
    import Text.Parsec.Char

    data SpaceGroup = P1 | P2 | P21 | C2 | P222
                    deriving (Enum, Show)

    pa :: Parser SpaceGroup
    pa = let ps = map (\s -> s <$ string (show s)) [P1 ..]
         in choice ps
            -- this need to be tweaked

Is this what you were looking for?
-F

From frederic-emmanuel.picca at synchrotron-soleil.fr  Fri Jun 21 12:37:37 2019
From: frederic-emmanuel.picca at synchrotron-soleil.fr (PICCA Frederic-Emmanuel)
Date: Fri, 21 Jun 2019 12:37:37 +0000
Subject: [Haskell-beginners] Parser using the show method
In-Reply-To: <20190621120936.lmmpldlwupb3xbkm@x60s.casa>
References: <A2A20EC3B8560D408356CAC2FC148E53015BBBC785@SUN-DAG3.synchrotron-soleil.fr>,
 <20190621120936.lmmpldlwupb3xbkm@x60s.casa>
Message-ID: <A2A20EC3B8560D408356CAC2FC148E53015BBBC8F3@SUN-DAG3.synchrotron-soleil.fr>

Hello

>    data SpaceGroup = P1 | P2 | P21 | C2 | P222
>                    deriving (Show, Read)
>
>    p = read <$> takeText

this is excalty what I wanted. In my case I use readMaybe.

Do you know if a version existe of readMaybe with Text instead of String

From frederic-emmanuel.picca at synchrotron-soleil.fr  Fri Jun 21 13:02:26 2019
From: frederic-emmanuel.picca at synchrotron-soleil.fr (PICCA Frederic-Emmanuel)
Date: Fri, 21 Jun 2019 13:02:26 +0000
Subject: [Haskell-beginners] Parser using the show method
In-Reply-To: <A2A20EC3B8560D408356CAC2FC148E53015BBBC8F3@SUN-DAG3.synchrotron-soleil.fr>
References: <A2A20EC3B8560D408356CAC2FC148E53015BBBC785@SUN-DAG3.synchrotron-soleil.fr>, 
 <20190621120936.lmmpldlwupb3xbkm@x60s.casa>,
 <A2A20EC3B8560D408356CAC2FC148E53015BBBC8F3@SUN-DAG3.synchrotron-soleil.fr>
Message-ID: <A2A20EC3B8560D408356CAC2FC148E53015BBBC91F@SUN-DAG3.synchrotron-soleil.fr>

Re-Hello,

is there a way to apply a function to all constructors of this  this type ?

Instead of doing this ?

do         sg P1
            sg P2
            sg P21
            sg C2
            sg P222
            sg P2221
            sg P21212
            sg P212121
            sg C222
            sg C2221
            sg F222
            sg I222
            sg I212121
            sg P4
            sg P41
            sg P42
            sg P43
            sg P422
            sg P4212
            sg P4122
            sg P41212
            sg P4222
            sg P42212
            sg P4322
            sg P43212
            sg I4
            sg I41
            sg I422
            sg I4122
            sg P3
            sg P31
            sg P32
            sg P312
            sg P321
            sg P3112
            sg P3121
            sg P3212
            sg P3221
            sg P6
            sg P61
            sg P62
            sg P63
            sg P64
            sg P65
            sg P622
            sg P6122
            sg P6522
            sg P6222
            sg P6422
            sg P6322
            sg R3
            sg R32
            sg P23
            sg P213
            sg P432
            sg P4232
            sg P4332
            sg P4132
            sg F23
            sg F432
            sg F4132
            sg I23
            sg I213
            sg I432
            sg I4132

From fa-ml at ariis.it  Fri Jun 21 13:05:27 2019
From: fa-ml at ariis.it (Francesco Ariis)
Date: Fri, 21 Jun 2019 15:05:27 +0200
Subject: [Haskell-beginners] Parser using the show method
In-Reply-To: <A2A20EC3B8560D408356CAC2FC148E53015BBBC8F3@SUN-DAG3.synchrotron-soleil.fr>
References: <A2A20EC3B8560D408356CAC2FC148E53015BBBC785@SUN-DAG3.synchrotron-soleil.fr>
 <20190621120936.lmmpldlwupb3xbkm@x60s.casa>
 <A2A20EC3B8560D408356CAC2FC148E53015BBBC8F3@SUN-DAG3.synchrotron-soleil.fr>
Message-ID: <20190621130527.o3jozmilr3lwnz3q@x60s.casa>

On Fri, Jun 21, 2019 at 12:37:37PM +0000, PICCA Frederic-Emmanuel wrote:
> Do you know if a version existe of readMaybe with Text instead of String

Voilà

    https://hackage.haskell.org/package/readable-0.3.1/docs/Data-Readable.html

Maybe is an instance of MonadPlus, so it should fit your bill

From fa-ml at ariis.it  Fri Jun 21 13:08:54 2019
From: fa-ml at ariis.it (Francesco Ariis)
Date: Fri, 21 Jun 2019 15:08:54 +0200
Subject: [Haskell-beginners] Parser using the show method
In-Reply-To: <A2A20EC3B8560D408356CAC2FC148E53015BBBC91F@SUN-DAG3.synchrotron-soleil.fr>
References: <A2A20EC3B8560D408356CAC2FC148E53015BBBC785@SUN-DAG3.synchrotron-soleil.fr>
 <20190621120936.lmmpldlwupb3xbkm@x60s.casa>
 <A2A20EC3B8560D408356CAC2FC148E53015BBBC8F3@SUN-DAG3.synchrotron-soleil.fr>
 <A2A20EC3B8560D408356CAC2FC148E53015BBBC91F@SUN-DAG3.synchrotron-soleil.fr>
Message-ID: <20190621130854.mo5eaqbrhdwkvajl@x60s.casa>

On Fri, Jun 21, 2019 at 01:02:26PM +0000, PICCA Frederic-Emmanuel wrote:
> Re-Hello,
> 
> is there a way to apply a function to all constructors of this  this type ?
> 
> Instead of doing this ?
> 
> do         sg P1
>             sg P2
>             sg P21
> [...]

Use the same `Enum` trick Tobias Brandt described.

    λ> :t sequence_ $ map print [FirstConstructor ..]

From frederic-emmanuel.picca at synchrotron-soleil.fr  Fri Jun 21 13:14:17 2019
From: frederic-emmanuel.picca at synchrotron-soleil.fr (PICCA Frederic-Emmanuel)
Date: Fri, 21 Jun 2019 13:14:17 +0000
Subject: [Haskell-beginners] Parser using the show method
In-Reply-To: <20190621130854.mo5eaqbrhdwkvajl@x60s.casa>
References: <A2A20EC3B8560D408356CAC2FC148E53015BBBC785@SUN-DAG3.synchrotron-soleil.fr>
 <20190621120936.lmmpldlwupb3xbkm@x60s.casa>
 <A2A20EC3B8560D408356CAC2FC148E53015BBBC8F3@SUN-DAG3.synchrotron-soleil.fr>
 <A2A20EC3B8560D408356CAC2FC148E53015BBBC91F@SUN-DAG3.synchrotron-soleil.fr>,
 <20190621130854.mo5eaqbrhdwkvajl@x60s.casa>
Message-ID: <A2A20EC3B8560D408356CAC2FC148E53015BBBC946@SUN-DAG3.synchrotron-soleil.fr>

> Use the same `Enum` trick Tobias Brandt described.

>     λ> :t sequence_ $ map print [FirstConstructor ..]

Yes, I just wanted to avoid typing all the list by hand. In order to avoid mistake when adding new constructors later.