型の紹介 カスタム型の作成 型シノニムを使用する typeキーワード
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UNIT2(型の紹介)、LESSON 12(カスタム型の作成)、12.1(型シノニムを使用する)、クイックチェック 12-1の解答を求めてみる。
コード
lesson/app/Main.hs
module Main where
import Lib
( patientInfo,
)
main :: IO ()
main = do
print $ patientInfo ("John", "Doe") 43 74
print $ patientInfo ("Jane", "Smith") 25 62
lesson/src/Lib.hs
module Lib
( patientInfo,
)
where
type PatientName = (String, String)
type Age = Int
type Height = Int
patientInfo :: PatientName -> Age -> Height -> String
patientInfo (fname, lname) age height =
mconcat
[ lname,
", ",
fname,
" (",
show age,
"yrs. ",
show height,
"in.)"
]
入出力結果(Terminal, Zsh)
% stack build
lesson-0.1.0.0: unregistering (local file changes: src/Lib.hs)
lesson> build (lib + exe)
Preprocessing library for lesson-0.1.0.0..
Building library for lesson-0.1.0.0..
[2 of 2] Compiling Lib
Preprocessing executable 'lesson-exe' for lesson-0.1.0.0..
Building executable 'lesson-exe' for lesson-0.1.0.0..
[1 of 2] Compiling Main [Lib changed]
Linking .stack-work/dist/x86_64-osx/Cabal-3.4.1.0/build/lesson-exe/lesson-exe ...
lesson> copy/register
Installing library in /Users/…/lesson/.stack-work/install/x86_64-osx/58a4c4d937f77ed7ad33a3d831dc078cdd38bc2500aef58d99dd5ff42214f933/9.0.2/lib/x86_64-osx-ghc-9.0.2/lesson-0.1.0.0-CIOIkpTgcfQI9akDJnwnSd
Installing executable lesson-exe in /Users/…/lesson/.stack-work/install/x86_64-osx/58a4c4d937f77ed7ad33a3d831dc078cdd38bc2500aef58d99dd5ff42214f933/9.0.2/bin
Registering library for lesson-0.1.0.0..
% stack exec lesson-exe
"Doe, John (43yrs. 74in.)"
"Smith, Jane (25yrs. 62in.)"
%