Basic Haskell configuration

Nothing very extensive, but this seems to be sufficient for learning atm.

ha-programming-haskell.org

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+#+TITLE: Programming Haskell
+#+AUTHOR: Howard X. Abrams
+#+DATE:   2022-08-24
+#+FILETAGS: :emacs:
+
+A literate programming file for configuring Emacs to use [[https://www.haskell.org/][Haskell]] .
+#+begin_src emacs-lisp :exports none
+  ;;; ha-programming-haskell --- configuring for haskell. -*- lexical-binding: t; -*-
+  ;;
+  ;; © 2022 Howard X. Abrams
+  ;;   Licensed under a Creative Commons Attribution 4.0 International License.
+  ;;   See http://creativecommons.org/licenses/by/4.0/
+  ;;
+  ;; Author: Howard X. Abrams <http://gitlab.com/howardabrams>
+  ;; Maintainer: Howard X. Abrams
+  ;; Created: August 24, 2022
+  ;;
+  ;; While obvious, GNU Emacs does not include this file or project.
+  ;;
+  ;; *NB:* Do not edit this file. Instead, edit the original literate file at:
+  ;;            ~/other/hamacs/ha-programming-haskell.org
+  ;;       And tangle the file to recreate this one.
+  ;;
+  ;;; Code:
+  #+end_src
+* Introduction
+While “they” claim a [[https://www.haskell.org/tutorial/][Gentle Introduction]], it doesn’t look /fun/. I bought the book, [[http://learnyouahaskell.com/chapters][Learn You a Haskell for Great Good!]], which looks better. Before an /Emacsian/ can dive into a new language, one needs to get an Emacs environment working.
+
+First, get it installed. On a Mac, do something like:
+#+begin_src sh
+  brew install haskell-stack
+#+end_src
+Which installs the [[https://docs.haskellstack.org/][Haskell Stack]] project that is basically an interface to the /kitchen sink/.
+
+And then run:
+#+begin_src sh
+  stack setup
+#+end_src
+
+And then you get access to an interactive session in a virtual environment with:
+#+begin_src sh
+  stack ghci
+#+end_src
+* Haskell Mode
+Seems that the venerable [[https://github.com/haskell/haskell-mode][haskell-mode]] is the best.
+#+begin_src emacs-lisp
+  (use-package haskell-mode
+    :custom
+    (haskell-process-type 'stack-ghci))
+#+end_src
+
+See [[https://input-output-hk.github.io/adrestia/resources/Emacs][this configuration]] for some advanced features.
+
+The [[https://github.com/mihaimaruseac/hindent][hindent package]] looks interesting:
+#+begin_src emacs-lisp
+  (use-package hindent
+    :custom (hindent-style "johan-tibell")
+    :hook (haskell-mode . #'hindent-mode))
+#+end_src
+* Haskell and Org
+#+begin_src emacs-lisp
+  (use-package ob-haskell
+    :straight (:type built-in)
+    :config
+    (add-to-list 'org-babel-load-languages '(haskell . t)))
+#+end_src
+
+And let’s see if this works:
+#+begin_src haskell :results replace value
+  nums = filter (> 2) [1 .. 5]
+  zip nums ['a' .. 'e']
+#+end_src
+
+#+RESULTS:
+| 3 | a |
+| 4 | b |
+| 5 | c |
+
+* Technical Artifacts                                :noexport:
+Let's =provide= a name so we can =require= this file:
+#+begin_src emacs-lisp :exports none
+  (provide 'ha-programming-haskell)
+  ;;; ha-programming-haskell.el ends here
+  #+end_src
+
+#+DESCRIPTION: configuring Emacs.
+
+#+PROPERTY:    header-args:sh :tangle no
+#+PROPERTY:    header-args:emacs-lisp  :tangle yes
+#+PROPERTY:    header-args    :results none :eval no-export :comments no mkdirp yes
+
+#+OPTIONS:     num:nil toc:nil todo:nil tasks:nil tags:nil date:nil
+#+OPTIONS:     skip:nil author:nil email:nil creator:nil timestamp:nil
+#+INFOJS_OPT:  view:nil toc:nil ltoc:t mouse:underline buttons:0 path:http://orgmode.org/org-info.js