計算機科学のブログ

name:                lesson
version:             0.1.0.0
github:              "githubuser/lesson"
license:             BSD3
author:              "Author name here"
maintainer:          "example@example.com"
copyright:           "2022 Author name here"

extra-source-files:
- README.md
- ChangeLog.md

# Metadata used when publishing your package
# synopsis:            Short description of your package
# category:            Web

# To avoid duplicated efforts in documentation and dealing with the
# complications of embedding Haddock markup inside cabal files, it is
# common to point users to the README.md file.
description:         Please see the README on GitHub at <https://github.com/githubuser/lesson#readme>

dependencies:
- base >= 4.7 && < 5
- split

library:
  source-dirs: src

executables:
  lesson-exe:
    main:                Main.hs
    source-dirs:         app
    ghc-options:
    - -threaded
    - -rtsopts
    - -with-rtsopts=-N
    dependencies:
    - lesson

tests:
  lesson-test:
    main:                Spec.hs
    source-dirs:         test
    ghc-options:
    - -threaded
    - -rtsopts
    - -with-rtsopts=-N
    dependencies:
    - lesson

module Main where

import Lib (toKakugens)

main :: IO ()
main = do
  userInput <- getContents
  mapM_ print $ toKakugens $ lines userInput

module Lib where

import Data.List.Split (splitOn)

kakugens :: [String]
kakugens =
  [ "kakugen1",
    "kakugen2",
    "kakugen3",
    "kakugen4",
    "kakugen5"
  ]

toKakugens :: [String] -> [String]
toKakugens [] = []
toKakugens ("n" : _) = []
toKakugens (x : xs) = kakugens !! (read x - 1) : toKakugens xs

% stack exec lesson-exe
1
"kakugen1"
2
"kakugen2"
3
"kakugen3"
4
"kakugen4"
5
"kakugen5"
6
lesson-exe: Prelude.!!: index too large
% stack exec lesson-exe
5
"kakugen5"
1
"kakugen1"
4
"kakugen4"
2
"kakugen2"
3
"kakugen3"
n
%