96b7f82 · rowtype-yoga/purescript-native

git.iko.soy/rowtype-yoga/purescript-native

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Make 'compare on' example idiomatic

96b7f82Phil Freeman12 years ago

prelude/README.md+4−5

compare with golang

unifiedsplit

@@ -252,7 +252,7 @@ types use the type constructor `f` to represent some computational context.

252(<#>) :: forall f a b. (Functor f) => f a -> (a -> b) -> f b

253```

254

255−`(<#>)` is `(<$>)` with its arguments flipped. For example:

255+`(<#>)` is `(<$>)` with its arguments reversed. For example:

256

257```purescript

258[1, 2, 3] <#> \n -> n * n

@@ -880,14 +880,13 @@ on :: forall a b c. (b -> b -> c) -> (a -> b) -> a -> a -> c

880

881The `on` function is used to change the domain of a binary operator.

882

883−For example, given a function `height :: Person -> Number`, we can create a function which compares two people by height:

883+For example, we can create a function which compares two records based on the values of their `x` properties:

884

885```purescript

886−taller :: Person -> Person -> Boolean

886+compareX :: forall r. { x :: Number | r } -> { x :: Number | r } -> Ordering

887−taller = (>) `on` height

887+compareX = compare `on` _.x

888```

889

890−

891#### `Fn0`

890#### `Fn0`

892

891

893``` purescript

892``` purescript

prelude/prelude.purs+4−5

@@ -234,7 +234,7 @@ module Prelude

234 class Functor f where

235 (<$>) :: forall a b. (a -> b) -> f a -> f b

236

237− -- | `(<#>)` is `(<$>)` with its arguments flipped. For example:

237+ -- | `(<#>)` is `(<$>)` with its arguments reversed. For example:

238 -- |

239 -- | ```purescript

240 -- | [1, 2, 3] <#> \n -> n * n

@@ -868,13 +868,12 @@ module Data.Function where

868

869 -- | The `on` function is used to change the domain of a binary operator.

870 -- |

871− -- | For example, given a function `height :: Person -> Number`, we can create a function which compares two people by height:

871+ -- | For example, we can create a function which compares two records based on the values of their `x` properties:

872 -- |

873 -- | ```purescript

874− -- | taller :: Person -> Person -> Boolean

874+ -- | compareX :: forall r. { x :: Number | r } -> { x :: Number | r } -> Ordering

875− -- | taller = (>) `on` height

875+ -- | compareX = compare `on` _.x

876 -- | ```

877− -- |

878 on :: forall a b c. (b -> b -> c) -> (a -> b) -> a -> a -> c

877 on :: forall a b c. (b -> b -> c) -> (a -> b) -> a -> a -> c

879 on f g x y = g x `f` g y

878 on f g x y = g x `f` g y

880

879