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    1 {-# LANGUAGE DeriveGeneric #-}
    2 {-# LANGUAGE FlexibleContexts #-}
    3 
    4 {-# OPTIONS_HADDOCK hide #-}
    5 
    6 module Options.Applicative.MnemonicSize
    7     (
    8     -- * Type
    9       MnemonicSize(..)
   10     , mnemonicSizeToString
   11     , mnemonicSizeFromString
   12 
   13     -- * Applicative Parser
   14     , mnemonicSizeOpt
   15     ) where
   16 
   17 import Prelude
   18 
   19 import Data.List
   20     ( intercalate )
   21 import Data.List.Extra
   22     ( enumerate )
   23 import GHC.Generics
   24     ( Generic )
   25 import Options.Applicative
   26     ( Parser
   27     , completer
   28     , eitherReader
   29     , help
   30     , listCompleter
   31     , long
   32     , metavar
   33     , option
   34     , showDefaultWith
   35     , value
   36     )
   37 
   38 
   39 --
   40 -- Type
   41 --
   42 
   43 data MnemonicSize
   44     = MS_9 | MS_12 | MS_15 | MS_18 | MS_21 | MS_24
   45     deriving (Generic, Show, Bounded, Enum, Eq)
   46 
   47 mnemonicSizeToString :: MnemonicSize -> String
   48 mnemonicSizeToString = drop 3 . show
   49 
   50 mnemonicSizeFromString :: String -> Either String MnemonicSize
   51 mnemonicSizeFromString str =
   52     case lookup str sizeMap of
   53         Just ms -> Right ms
   54         Nothing -> Left $ mempty
   55             <> "Invalid mnemonic size. Expected one of: "
   56             <> intercalate ", " sizeStrs
   57             <> "."
   58   where
   59     sizeMap  = sizeStrs `zip` enumerate
   60 
   61 sizeStrs :: [String]
   62 sizeStrs = mnemonicSizeToString <$> enumerate
   63 
   64 --
   65 -- Applicative Parser
   66 --
   67 
   68 mnemonicSizeOpt :: Parser MnemonicSize
   69 mnemonicSizeOpt = option (eitherReader mnemonicSizeFromString) $ mempty
   70     <> long "size"
   71     <> metavar "INT"
   72     <> help "Number of mnemonic words to generate. Must be a multiple of 3."
   73     <> value MS_24
   74     <> showDefaultWith mnemonicSizeToString
   75     <> completer (listCompleter sizeStrs)