 | category-extras-0.53.6: Various modules and constructs inspired by category theory | Contents | Index |
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| Control.Comonad.Supply | | Portability | portable | | Stability | provisional | | Maintainer | Edward Kmett <ekmett@gmail.com> |
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| Description |
The technique for generating new values is based on the paper
''On Generating Unique Names''
by Lennart Augustsson, Mikael Rittri, and Dan Synek.
Integrated from value-supply-0.1
TODO: a SupplyT Comonad Transformer
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| Synopsis |
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| Documentation |
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| module Control.Comonad |
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| Creating supplies
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| data Supply a |
| A type that can be used to generate values on demand.
A supply may be turned into two different supplies by using
the functions supplyLeft and supplyRight.
|  Instances | |
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| newSupply :: a -> (a -> a) -> IO (Supply a) |
| Creates a new supply of values.
The arguments specify how to generate values:
the first argument is an initial value, the
second specifies how to generate a new value from an existing one.
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| newEnumSupply :: Enum a => IO (Supply a) |
| A supply of values that are in the Enum class.
The initial value is toEnum 0, new values are generates with succ.
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| newNumSupply :: Num a => IO (Supply a) |
| A supply of values that are in the Num class.
The initial value is 0, new values are generated by adding 1.
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| Obtaining values from supplies
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| supplyValue :: Supply a -> a |
| Get the value of a supply. This function, together with
modifySupply forms a comonad on Supply.
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| Generating new supplies from old
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| supplyLeft :: Supply a -> Supply a |
| Generate a new supply. This supply is different from the one
generated with supplyRight.
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| supplyRight :: Supply a -> Supply a |
| Generate a new supply. This supply is different from the one
generated with supplyLeft.
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| modifySupply :: Supply a -> (Supply a -> b) -> Supply b |
| Generate a new supply by systematically applying a function
to an existing supply. This function, together with supplyValue
form a comonad on Supply.
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| split :: Supply a -> [Supply a] |
| Generate an infinite list of supplies by using supplyLeft and
supplyRight repeatedly.
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| split2 :: Supply a -> (Supply a, Supply a) |
| Split a supply into two different supplies.
The resulting supplies are different from the input supply.
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| split3 :: Supply a -> (Supply a, Supply a, Supply a) |
| Split a supply into three different supplies.
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| split4 :: Supply a -> (Supply a, Supply a, Supply a, Supply a) |
| Split a supply into four different supplies.
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| Produced by Haddock version 2.1.0 |