https://github.com/fgaz/polyvariadic

Create and apply polyvariadic functions
https://github.com/fgaz/polyvariadic

function haskell polyvariadic varargs

Last synced: 10 days ago
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Create and apply polyvariadic functions

• Host: GitHub
• URL: https://github.com/fgaz/polyvariadic
• Owner: fgaz
• License: bsd-3-clause
• Created: 2017-04-08T13:13:02.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2022-06-03T16:11:32.000Z (over 2 years ago)
• Last Synced: 2024-10-11T22:44:09.338Z (26 days ago)
• Topics: function, haskell, polyvariadic, varargs
• Language: Haskell
• Homepage: https://hackage.haskell.org/package/polyvariadic
• Size: 27.3 KB
• Stars: 12
• Watchers: 4
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: ChangeLog.md
  • License: LICENSE

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README

        
# polyvariadic

**Creation and application of polyvariadic functions**

[![builds.sr.ht status](https://builds.sr.ht/~fgaz/polyvariadic/commits.svg)](https://builds.sr.ht/~fgaz/polyvariadic/commits?)

[![Hackage](https://img.shields.io/hackage/v/polyvariadic.svg)](https://hackage.haskell.org/package/polyvariadic)

For example, the classic printf:

```haskell

{-# LANGUAGE MultiParamTypeClasses #-}

{-# LANGUAGE FlexibleInstances #-}

{-# LANGUAGE FlexibleContexts #-}

import Data.Function.Polyvariadic

import Data.Accumulator

magicChar = '%'

notMagicChar = (/= magicChar)

data PrintfAccum = PrintfAccum { done :: String, todo :: String }

instance Show x => Accumulator PrintfAccum x where

  accumulate x (PrintfAccum done (_:todo)) = PrintfAccum

                                              (done ++ show x ++ takeWhile notMagicChar todo)

                                              (dropWhile notMagicChar todo)

  accumulate _ acc = acc

printf' str = polyvariadic

               (PrintfAccum (takeWhile notMagicChar str) (dropWhile notMagicChar str))

               done

```

```haskell

>>> printf' "aaa%bbb%ccc%ddd" "TEST" 123 True

"aaa\"TEST\"bbb123cccTrueddd"

```