Re: [Haskell-cafe] Understanding version differences
Thanks to Roman and Eric for for their clear explanations.PatOn 09/07/13, Roman Cheplyaka wrote:The compiler defaults the kind of 'quality' (i.e. the first argument ofQUALITIES) to *, not being able to infer it from the class definitionitself (and other definitions that it references).Since you want it to have kind * -> *, you should enable KindSignaturesand add an annotation, or otherwise disambiguate the kind.This behaviour follows the Haskell Report. The change from previousversions of GHC is documented here:http://www.haskell.org/ghc/docs/7.4.1/html/users_guide/release-7-4-1.html#id3015054Roman* Patrick Browne [2013-07-09 12:45:19+0100]> Hi,> The code [1] below compiles and runs with GHCi version 7.0.4.> I get one warning and an error message with GHCi version 7.6.1.> 1) Warning -XDatatypeContexts is deprecated. Unless there are> propagation effects, this is well explained.> 2) foom-1.hs:65:15:> `quality' is applied to too many type arguments> In the type `quality entity -> agent -> IO Observation'> In the class declaration for `OBSERVERS'> Failed, modules loaded: none.> I do not understand the error message from 7.6.1.> I am not too interested actually fixing it, I just want to understand> it.> Thanks,> Pat> [1]The code is from: A Functional Ontology of Observation and> Measurement Werner Kuhn> {-# LANGUAGE DatatypeContexts,MultiParamTypeClasses #-}> module ENDURANTS where> import System.Time> type Id = String> type Position = Integer> type Moisture = Float> type Celsius = String> type Heat = Float> data WeatherStation = WeatherStation Id Position deriving Show> data Value = Boolean Bool | Count Int | Measure Float | Category String> deriving Show> data Observation = Observation Value Position ClockTime deriving Show> data AmountOfAir = AmountOfAir Heat Moisture deriving Show> muensterAir = AmountOfAir 10.0 70.0> class ENDURANTS endurant where> > -- must add instances all down the hierarchy for each instance> instance ENDURANTS WeatherStation where> instance ENDURANTS AmountOfAir where> class ENDURANTS physicalEndurant => PHYSICAL_ENDURANTS physicalEndurant> where> instance PHYSICAL_ENDURANTS WeatherStation where> instance PHYSICAL_ENDURANTS AmountOfAir where> class PHYSICAL_ENDURANTS amountOfMatter => AMOUNTS_OF_MATTER> amountOfMatter where> instance AMOUNTS_OF_MATTER WeatherStation where> class PHYSICAL_ENDURANTS physicalObject => PHYSICAL_OBJECTS> physicalObject where> instance PHYSICAL_OBJECTS WeatherStation where> class PHYSICAL_OBJECTS apo => APOS apo where> getPosition :: apo -> Position> instance APOS WeatherStation where> getPosition (WeatherStation iD pos) = pos + 10> > -- a data type declaration and data type constructor.> data PHYSICAL_ENDURANTS physicalEndurant => Temperature> physicalEndurant = Temperature physicalEndurant deriving Show> -- Qualities the class of all quality types (= properties) is a> constructor class> -- its constructors can be applied to endurants, perdurants, qualities> or abstracts> class QUALITIES quality entity> instance QUALITIES Temperature AmountOfAir> class (APOS agent, QUALITIES quality entity) => OBSERVERS agent quality> entity where> observe :: quality entity -> agent -> IO Observation> express :: quality entity -> agent -> Value> observe quale agent = do> clockTime <- getClockTime> return (Observation (express quale agent)> (getPosition agent) clockTime)> instance OBSERVERS WeatherStation Temperature AmountOfAir where> express (Temperature (AmountOfAir heat moisture)) weatherStation => Measure heat> {-> -- running the following> express (Temperature (AmountOfAir 40 20)) (WeatherStation "rr" 6)> -- Gives> Measure 40.0 Measure 40.0> -- We can get the type: Value> :t express (Temperature (AmountOfAir 40 20)) (WeatherStation "rr" 6)> -}> > Tá an teachtaireacht seo scanta ó thaobh ábhar agus víreas ag Seirbhís> Scanta Ríomhphost de chuid Seirbhísí Faisnéise, ITBÁC agus meastar í a> bheith slán. [1]http://www.dit.ie> This message has been scanned for content and viruses by the DIT> Information Services E-Mail Scanning Service, and is believed to be> clean. [2]http://www.dit.ie> > References> > 1. http://www.dit.ie/> 2. http://www.dit.ie/> ___> Haskell-Cafe mailing list> Haskell-Cafe@haskell.org> http://www.haskell.org/mailman/listinfo/haskell-cafe
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Re: [Haskell-cafe] Understanding version differences
The compiler defaults the kind of 'quality' (i.e. the first argument of
QUALITIES) to *, not being able to infer it from the class definition
itself (and other definitions that it references).
Since you want it to have kind * -> *, you should enable KindSignatures
and add an annotation, or otherwise disambiguate the kind.
This behaviour follows the Haskell Report. The change from previous
versions of GHC is documented here:
http://www.haskell.org/ghc/docs/7.4.1/html/users_guide/release-7-4-1.html#id3015054
Roman
* Patrick Browne [2013-07-09 12:45:19+0100]
>Hi,
>The code [1] below compiles and runs with GHCi version 7.0.4.
>I get one warning and an error message with GHCi version 7.6.1.
>1) Warning -XDatatypeContexts is deprecated. Unless there are
>propagation effects, this is well explained.
>2) foom-1.hs:65:15:
>`quality' is applied to too many type arguments
>In the type `quality entity -> agent -> IO Observation'
>In the class declaration for `OBSERVERS'
>Failed, modules loaded: none.
>I do not understand the error message from 7.6.1.
>I am not too interested actually fixing it, I just want to understand
>it.
>Thanks,
>Pat
>[1]The code is from: A Functional Ontology of Observation and
>Measurement Werner Kuhn
>{-# LANGUAGE DatatypeContexts,MultiParamTypeClasses #-}
>module ENDURANTS where
>import System.Time
>type Id = String
>type Position = Integer
>type Moisture = Float
>type Celsius = String
>type Heat = Float
>data WeatherStation = WeatherStation Id Position deriving Show
>data Value = Boolean Bool | Count Int | Measure Float | Category String
>deriving Show
>data Observation = Observation Value Position ClockTime deriving Show
>data AmountOfAir = AmountOfAir Heat Moisture deriving Show
>muensterAir = AmountOfAir 10.0 70.0
>class ENDURANTS endurant where
>
>-- must add instances all down the hierarchy for each instance
>instance ENDURANTS WeatherStation where
>instance ENDURANTS AmountOfAir where
>class ENDURANTS physicalEndurant => PHYSICAL_ENDURANTS physicalEndurant
>where
>instance PHYSICAL_ENDURANTS WeatherStation where
>instance PHYSICAL_ENDURANTS AmountOfAir where
>class PHYSICAL_ENDURANTS amountOfMatter => AMOUNTS_OF_MATTER
>amountOfMatter where
>instance AMOUNTS_OF_MATTER WeatherStation where
>class PHYSICAL_ENDURANTS physicalObject => PHYSICAL_OBJECTS
>physicalObject where
>instance PHYSICAL_OBJECTS WeatherStation where
>class PHYSICAL_OBJECTS apo => APOS apo where
> getPosition :: apo -> Position
>instance APOS WeatherStation where
> getPosition (WeatherStation iD pos) = pos + 10
>
>-- a data type declaration and data type constructor.
>data PHYSICAL_ENDURANTS physicalEndurant => Temperature
>physicalEndurant = Temperature physicalEndurant deriving Show
>-- Qualities the class of all quality types (= properties) is a
>constructor class
>-- its constructors can be applied to endurants, perdurants, qualities
>or abstracts
>class QUALITIES quality entity
>instance QUALITIES Temperature AmountOfAir
>class (APOS agent, QUALITIES quality entity) => OBSERVERS agent quality
>entity where
> observe :: quality entity -> agent -> IO Observation
> express :: quality entity -> agent -> Value
> observe quale agent = do
> clockTime <- getClockTime
> return (Observation (express quale agent)
> (getPosition agent) clockTime)
>instance OBSERVERS WeatherStation Temperature AmountOfAir where
> express (Temperature (AmountOfAir heat moisture)) weatherStation =
>Measure heat
>{-
>-- running the following
>express (Temperature (AmountOfAir 40 20)) (WeatherStation "rr" 6)
>-- Gives
>Measure 40.0 Measure 40.0
>-- We can get the type: Value
>:t express (Temperature (AmountOfAir 40 20)) (WeatherStation "rr" 6)
>-}
>
>Tá an teachtaireacht seo scanta ó thaobh ábhar agus víreas ag Seirbhís
>Scanta Ríomhphost de chuid Seirbhísí Faisnéise, ITBÁC agus meastar í a
>bheith slán. [1]http://www.dit.ie
>This message has been scanned for content and viruses by the DIT
>Information Services E-Mail Scanning Service, and is believed to be
>clean. [2]http://www.dit.ie
>
> References
>
>1. http://www.dit.ie/
>2. http://www.dit.ie/
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[Haskell-cafe] Understanding version differences
Hi,The code [1] below compiles and runs with GHCi version 7.0.4.I get one warning and an error message with GHCi version 7.6.1.1) Warning -XDatatypeContexts is deprecated. Unless there are propagation effects, this is well explained.2) foom-1.hs:65:15: `quality' is applied to too many type arguments In the type `quality entity -> agent -> IO Observation' In the class declaration for `OBSERVERS'Failed, modules loaded: none.I do not understand the error message from 7.6.1. I am not too interested actually fixing it, I just want to understand it.Thanks,Pat[1]The code is from: A Functional Ontology of Observation and Measurement Werner Kuhn{-# LANGUAGE DatatypeContexts,MultiParamTypeClasses #-}module ENDURANTS whereimport System.Timetype Id = Stringtype Position = Integertype Moisture = Floattype Celsius = Stringtype Heat = Float data WeatherStation = WeatherStation Id Position deriving Showdata Value = Boolean Bool | Count Int | Measure Float | Category String deriving Showdata Observation = Observation Value Position ClockTime deriving Showdata AmountOfAir = AmountOfAir Heat Moisture deriving ShowmuensterAir = AmountOfAir 10.0 70.0class ENDURANTS endurant where -- must add instances all down the hierarchy for each instanceinstance ENDURANTS WeatherStation whereinstance ENDURANTS AmountOfAir whereclass ENDURANTS physicalEndurant => PHYSICAL_ENDURANTS physicalEndurant whereinstance PHYSICAL_ENDURANTS WeatherStation whereinstance PHYSICAL_ENDURANTS AmountOfAir whereclass PHYSICAL_ENDURANTS amountOfMatter => AMOUNTS_OF_MATTER amountOfMatter whereinstance AMOUNTS_OF_MATTER WeatherStation whereclass PHYSICAL_ENDURANTS physicalObject => PHYSICAL_OBJECTS physicalObject whereinstance PHYSICAL_OBJECTS WeatherStation whereclass PHYSICAL_OBJECTS apo => APOS apo where getPosition :: apo -> Positioninstance APOS WeatherStation where getPosition (WeatherStation iD pos) = pos + 10 -- a data type declaration and data type constructor.data PHYSICAL_ENDURANTS physicalEndurant => Temperature physicalEndurant = Temperature physicalEndurant deriving Show-- Qualities the class of all quality types (= properties) is a constructor class-- its constructors can be applied to endurants, perdurants, qualities or abstractsclass QUALITIES quality entity instance QUALITIES Temperature AmountOfAirclass (APOS agent, QUALITIES quality entity) => OBSERVERS agent quality entity where observe :: quality entity -> agent -> IO Observation express :: quality entity -> agent -> Value observe quale agent = do clockTime <- getClockTime return (Observation (express quale agent) (getPosition agent) clockTime)instance OBSERVERS WeatherStation Temperature AmountOfAir where express (Temperature (AmountOfAir heat moisture)) weatherStation = Measure heat {--- running the followingexpress (Temperature (AmountOfAir 40 20)) (WeatherStation "rr" 6)-- GivesMeasure 40.0 Measure 40.0-- We can get the type: Value :t express (Temperature (AmountOfAir 40 20)) (WeatherStation "rr" 6)-}
Tá an teachtaireacht seo scanta ó thaobh ábhar agus víreas ag Seirbhís Scanta Ríomhphost de chuid Seirbhísí Faisnéise, ITBÁC agus meastar í a bheith slán. http://www.dit.ie
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