polyvariadic: Creation and application of polyvariadic functions

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Creation and application of polyvariadic functions, see the docs for usage and examples


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Versions [RSS] 0.3.0.0, 0.3.0.1, 0.3.0.2, 0.3.0.3, 0.3.0.4 (info)
Change log ChangeLog.md
Dependencies base (>=4.7 && <4.17), containers (>=0.1 && <0.7), semigroups (>=0.18 && <0.19) [details]
Tested with ghc ==7.8.4, ghc ==7.10.3, ghc ==8.0.2, ghc ==8.2.2, ghc ==8.4.4, ghc ==8.6.5, ghc ==8.8.2, ghc ==8.10.2, ghc ==9.0.2, ghc ==9.2.2
License BSD-3-Clause
Copyright (C) Francesco Gazzetta 2017-2020
Author Francesco Gazzetta
Maintainer Francesco Gazzetta <fgaz@fgaz.me>
Revised Revision 2 made by fgaz at 2022-06-03T16:16:03Z
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Home page https://github.com/fgaz/polyvariadic
Source repo head: git clone git://github.com/fgaz/polyvariadic.git
Uploaded by fgaz at 2020-02-04T08:31:03Z
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Reverse Dependencies 2 direct, 0 indirect [details]
Downloads 2875 total (22 in the last 30 days)
Rating 2.0 (votes: 1) [estimated by Bayesian average]
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Status Docs available [build log]
Last success reported on 2020-02-04 [all 1 reports]

Readme for polyvariadic-0.3.0.4

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polyvariadic

Creation and application of polyvariadic functions

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For example, the classic printf:

{-# 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
>>> printf' "aaa%bbb%ccc%ddd" "TEST" 123 True
"aaa\"TEST\"bbb123cccTrueddd"