lambda-options: Declarative command-line parser with type-driven pattern matching.

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Declarative command-line parser with type-driven pattern matching.


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Versions 0.1.0.0, 0.2.0.0, 0.3.0.0, 0.4.0.0, 0.4.0.1, 0.4.0.2, 0.5.0.0, 0.5.1.0, 0.6.0.0, 0.7.0.0, 0.8.0.0, 0.9.0.0, 0.9.0.1, 0.9.1.0, 1.0.0.0, 1.0.1.0, 1.0.2.0, 1.1.0.0, 1.1.0.1, 1.1.0.1
Change log None available
Dependencies base (>=4.13.0.0 && <4.14), containers (>=0.6.0.1 && <0.7), funspection (>=1.0.0.1 && <1.1), mtl (>=2.2.2 && <2.3), read-bounded (>=0.1.1.3 && <0.2) [details]
License BSD-3-Clause
Author Thomas Eding
Maintainer Thomas Eding
Category Text
Home page https://github.com/thomaseding/lambda-options
Bug tracker https://github.com/thomaseding/lambda-options/issues
Uploaded by ThomasEding at 2020-09-11T19:24:01Z

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Readme for lambda-options-1.1.0.1

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lambda-options-haskell

Declarative command line parser using type-driven pattern matching.

Homepage: https://github.com/thomaseding/lambda-options

Hackage: https://hackage.haskell.org/package/lambda-options


Basic example:

import qualified System.Environment as Env
import qualified Text.LambdaOptions as L

options :: L.Options (IO ())
options = do

  L.addOption
    (L.kw ["--help", "-h"]
    `L.text` "Display this help text.")
    $ do
      putStrLn "Usage:"
      putStrLn $ L.getHelpDescription options

  L.addOption
    (L.kw "--add"
    `L.argText` "X Y"
    `L.text` "Adds two Doubles and prints their sum.")
    $ \x y -> do
      print $ x + (y :: Double)

main :: IO ()
main = do
  args <- Env.getArgs
  case L.runOptions options args of
    Left e -> do
      putStrLn $ L.prettyOptionsError e
      putStrLn $ L.getHelpDescription options
    Right results -> do
      sequence_ results
>>> :main --add 3 0.14
3.14
>>> :main -h
Usage:
     --add X Y               Adds two Doubles and prints their sum.
 -h, --help                  Display this help text.
>>> :main --add 0 1 --add 2 four
Bad input for `--add' at index 3: `four'
     --add X Y               Adds two Doubles and prints their sum.
 -h, --help                  Display this help text.