pretty-display 0.1.4 → 0.1.5
raw patch · 3 files changed
+63/−63 lines, 3 files
Files
- README-h.md +0/−61
- README.md +61/−0
- pretty-display.cabal +2/−2
− README-h.md
@@ -1,61 +0,0 @@-# pretty-display: typeclass for human-readable display--[](https://travis-ci.org/jsermeno/pretty-display)-[](Haskell.org)---In Haskell the `Show` typeclass is used to display a syntactically correct Haskell expression. However, there are times when you want to provide a richer display for a value while still retaining the benefits of having derived `Show` instances. This can be especially useful when working interactively in ghci. `pretty-display` provides a tiny registered package with the `Display` typeclass for just this purpose.--## GHCi usage--To use `Display` instances as the default in ghci create a `.ghci` file with the following:--```-import Text.Display--:set -interactive-print=Text.Display.dPrint-:def pp (\_ -> return ":set -interactive-print=Text.Display.dPrint")-:def npp (\_ -> return ":set -interactive-print=print")-```----## Typeclass usage--By default, all instances of `Show` are also instances of `Display`. To create a custom instance you will need to use the `OVERLAPPING` pragma, and define the `display` method of type `a -> DisplayText`. For example:--```-import Numeric--import Text.Display-import Text.PrettyPrint.ANSI.Leijen as PP--data MyRecord = MyRecord- { numerators :: [Double]- , denominator :: Double- } deriving (Show)--record :: MyRecord-record = MyRecord- { numerators = [0, 5..100]- , denominator = 1326- }--instance {-# OVERLAPPING #-} Display MyRecord where- display a = mkDisplayTextFromStr- $ show- $ toCol "MyRecord (percentage): " <> toCol (displayPerc a)- where- displayPerc a = showFFloat (Just 2) (toPerc a) "%"- toPerc a = sum (numerators a) / denominator a * 100- toCol a = (PP.dullgreen . PP.fill 25 . PP.text) a--main :: IO ()-main = do- dPrint record- pPrint record-```--## Using `Show` when defaulting to `Display`--If you've set ghci to use `dPrint` by default you can still print `Show` instances for debugging. For normal printing use `print`. For convenience `pretty-display` re-exports `pPrint` from the `pretty-show` package for pretty printing `Show` instances.
+ README.md view
@@ -0,0 +1,61 @@+# pretty-display: typeclass for human-readable display++[](https://travis-ci.org/jsermeno/pretty-display)+[](Haskell.org)+++In Haskell the `Show` typeclass is used to display a syntactically correct Haskell expression. However, there are times when you want to provide a richer display for a value while still retaining the benefits of having derived `Show` instances. This can be especially useful when working interactively in ghci. `pretty-display` provides a tiny registered package with the `Display` typeclass for just this purpose.++## GHCi usage++To use `Display` instances as the default in ghci create a `.ghci` file with the following:++```+import Text.Display++:set -interactive-print=Text.Display.dPrint+:def pp (\_ -> return ":set -interactive-print=Text.Display.dPrint")+:def npp (\_ -> return ":set -interactive-print=print")+```++<img src="https://cloud.githubusercontent.com/assets/197051/20393285/4d04a098-aca9-11e6-85ea-a025c5e752f1.png" alt="ghci example" width="638" height="213" />++## Typeclass usage++By default, all instances of `Show` are also instances of `Display`. To create a custom instance you will need to use the `OVERLAPPING` pragma, and define the `display` method of type `a -> DisplayText`. For example:++```+import Numeric++import Text.Display+import Text.PrettyPrint.ANSI.Leijen as PP++data MyRecord = MyRecord+ { numerators :: [Double]+ , denominator :: Double+ } deriving (Show)++record :: MyRecord+record = MyRecord+ { numerators = [0, 5..100]+ , denominator = 1326+ }++instance {-# OVERLAPPING #-} Display MyRecord where+ display a = mkDisplayTextFromStr+ $ show+ $ toCol "MyRecord (percentage): " <> toCol (displayPerc a)+ where+ displayPerc a = showFFloat (Just 2) (toPerc a) "%"+ toPerc a = sum (numerators a) / denominator a * 100+ toCol a = (PP.dullgreen . PP.fill 25 . PP.text) a++main :: IO ()+main = do+ dPrint record+ pPrint record+```++## Using `Show` when defaulting to `Display`++If you've set ghci to use `dPrint` by default you can still print `Show` instances for debugging. For normal printing use `print`. For convenience `pretty-display` re-exports `pPrint` from the `pretty-show` package for pretty printing `Show` instances.
pretty-display.cabal view
@@ -1,5 +1,5 @@ name: pretty-display-version: 0.1.4+version: 0.1.5 synopsis: Typeclass for human-readable display description: Typeclass for human-readable display. Provides tools for working interactively within ghci.@@ -11,7 +11,7 @@ copyright: Copyright (c) 2014-2016 Justin Sermeno category: Text build-type: Simple-extra-source-files: README-h.md+extra-source-files: README.md cabal-version: >=1.10 library