descarteslabs/haskell-2020

Material for the DL Haskell 2020 class

haskell-2020

Material for the DL Haskell 2020 class

The Text

• primarily Programming in Haskell

Getting started

Installing

The simplest way to get started is installing ghcup ghcup with curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh.

If the above gives you a difficult time there are other options.

This gives you the following:

• GHC, Glasgow Haskell Compiler
• Cabal, a build system which should generally be avoided like the plague.
• Stack, a haskell project management / build system (almost a hazmat suit for using cabal).
• Other suff (profilers, code coverage, etc)

note: make sure to have the following installed: sudo apt upgrade build-essential curl libgmp-dev libffi-dev libncurses-dev libtinfo5

Hello World

here we go:

$ cd $(mktemp -d)
$ echo 'main = putStrLn "Hello World"' > main.hs
$ runghc main.hs
Hello World

Not too bad.

In the above example we evaluated main.hs using an interpreter. We can also compile haskell:

$ ghc main.hs 
$ ./main
Hello World

We can also interactivly execute haskell code using ghci, the haskell repl:

$ ghci main.hs
GHCi, version 8.6.5: http://www.haskell.org/ghc/  :? for help
[1 of 1] Compiling Main             ( main.hs, interpreted )
Ok, one module loaded.
*Main> -- this is a haskell commnet
*Main> main -- run the main function
Hello World