HaskellのI/O テキストとUnicodeの操作 Data.Text.Lazyモジュール、Data.Text.Lazy.IOモジュール
入門Haskellプログラミング (Will Kurt(著)、株式会社クイープ(監修、翻訳)、翔泳社)のUNIT4(HaskellのI/O)、LESSON 23(テキストとUnicodeの操作)、23.6(練習問題)Q23-2の解答を求めてみる。
lesson/package.yaml
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
- text
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
default-extensions: OverloadedStrings
コード
lesson/app/Main.hs
module Main where
import qualified Data.Text.Lazy.IO as TLIO
import Lib (toInts)
main :: IO ()
main = do
userInput <- TLIO.getContents
let numbers = toInts userInput
print $ sum numbers
lesson/src/Lib.hs
module Lib
( toInts,
)
where
import qualified Data.Text.Lazy as TL
toInts :: TL.Text -> [Int]
toInts text = map (read . TL.unpack) $ TL.lines text
入出力結果(Terminal, Zsh)
% stack exec lesson-exe
1
2
3
6D
% stack exec lesson-exe
12
34
56
102
%