Haskell configuring vs code development environment (june2022)

0. brief introduction

Haskell It's a kind of standardized 、 General purpose pure functional programming language , There are non finite semantics and strong static types .
stay Haskell in , Functions are first class citizens .
As a functional programming language , The main control structure is function .
Haskell Language is 1990 In programming language Miranda Standardized on the basis of , And take λ calculus (Lambda-Calculus) Developed on the basis of .
have “ Proof is procedure 、 The conclusion formula is the program type ” Characteristics of .
This is also Haskell Language in Greek letters 「λ」(Lambda) As a sign of their own reasons .
Haskell The main execution environment of a language is GHC.

Haskell Official website ：https://www.haskell.org/

1. install VS code Haskell development environment

0. You need an agent , Otherwise, the installation package cannot be downloaded , It's recommended here Express *** Yes 30 Days refund guarantee .
   To use Haskell It won't be too difficult for people to deal with the agency
   If it's hard , Suggest learning Scala

1. install GHCup （ Suggestions from the official website ）

This GHCup It's like Rust Of rustup, It is Haskell Development tool chain installer

stay Linux、macOS、FreeBSD or WSL2 Installation on
Run the following command in the terminal （ Act as not root user ）

curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh

stay Windows Installation on
stay PowerShell Run the following command in the session （ As a non administrator user ）：

Set-ExecutionPolicy Bypass -Scope Process -Force;[System.Net.ServicePointManager]::SecurityProtocol = [System.Net.ServicePointManager]::SecurityProtocol -bor 3072;Invoke-Command -ScriptBlock ([ScriptBlock]::Create((Invoke-WebRequest https://www.haskell.org/ghcup/sh/bootstrap-haskell.ps1 -UseBasicParsing))) -ArgumentList $true

You need to know a little English here

When selecting a position, note that there is no space in the path

HLS and Stack Put them all on

2. install VS code plug-in unit

install VS code skip ( It's estimated that there are all ), lately VS code The update is a little small bug

Generally, you can install the following three

haskell.haskell

justusadam.language-haskell

hoovercj.haskell-linter

You can also install another Code Runner ( because Ghc compile haskell Very slowly )

formulahendry.code-runner

3. install hlint

hlint It's a haskell Code specification detection program （ The prompt is not accurate ）

Input at the console ~ enter

cabal install hlint

Here we are Haskell The development environment is configured

2. Simple to fit

Create a new empty folder
Call test Well You can also create a new one called CODE_HASKELL Of

Then open it in the folder Terminal perform

cabal init

The folder will be initialized to Haskell The basic development environment

And then we use VS code open test Folder
open app / Main.hs

Commands to run the entire project

cabal run

Then it will compile and run ( The first time it will be slower )

But if it's just a single file, you can use Code Runner
It's used runhaskell command , It's going to be a lot faster

good Come here Your first Haskell And the program runs

Next, you can also learn about
cabal and stack command

cabal -h

stack --help

3. Carried some common commands and links

3.1 GHCup（ The one installed above ）

GHCup User Guide link

#  For simple interactive  TUI（ stay  Windows  Not available on 
ghcup tui

#  List the available  ghc/cabal  edition 
ghcup list

#  Install the recommended  GHC  edition 
ghcup install ghc

#  Install specific  GHC  edition 
ghcup install ghc 8.2.2

#  Set up current “ active ” Of  GHC  edition 
ghcup set ghc 8.4.4

#  install  cabal  install 
ghcup install cabal

#  to update  ghcup  In itself 
ghcup upgrade

3.2 GHCup install

https://www.haskell.org/ghcup/install/#next-steps