さくらのレンタルサーバスタンダードに Haskell 環境を構築する手順は FreeBSD 9.1 に Haskell 開発環境を構築する手順でしたが、私の環境もようやく 2022-08-31 に FreeBSD 12 に更新され、まともな開発環境が再構築できるようになりました。

この FreeBSD 12 に Haskell 開発環境を構築します。

GHCup 導入

GHCup は GHC や Stack などのインストールを管理するツールです。Stack 上の curl コマンドで stack コマンドを直接インストールすれば簡単なのですが、FreeBSD は Stack のスクリプトでサポートされていないため、GHCup 経由で行きます。しかしながら長期的に複数の GHC や Stack を管理することになるかも知れないため、GHCup は良い選択かも知れません。

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

Welcome to Haskell!

This script can download and install the following binaries:
  * ghcup - The Haskell toolchain installer
  * ghc   - The Glasgow Haskell Compiler
  * cabal - The Cabal build tool for managing Haskell software
  * stack - (optional) A cross-platform program for developing Haskell projects
  * hls   - (optional) A language server for developers to integrate with their editor/IDE

ghcup installs only into the following directory,
which can be removed anytime:
  /home/xxx/.ghcup

Press ENTER to proceed or ctrl-c to abort.
Note that this script can be re-run at any given time.

-------------------------------------------------------------------------------

Detected bash shell on your system...
Do you want ghcup to automatically add the required PATH variable to "/home/xxx/.bashrc"?

[P] Yes, prepend  [A] Yes, append  [N] No  [?] Help (default is "P").

A
-------------------------------------------------------------------------------
Do you want to install haskell-language-server (HLS)?
HLS is a language-server that provides IDE-like functionality
and can integrate with different editors, such as Vim, Emacs, VS Code, Atom, ...
Also see https://haskell-language-server.readthedocs.io/en/stable/

[Y] Yes  [N] No  [?] Help (default is "N").

N
-------------------------------------------------------------------------------
Do you want to install stack?
Stack is a haskell build tool similar to cabal that is used by some projects.
Also see https://docs.haskellstack.org/

[Y] Yes  [N] No  [?] Help (default is "N").

Y
13.0-RELEASE-p12
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 67.3M  100 67.3M    0     0  25.3M      0  0:00:02  0:00:02 --:--:-- 25.3M
[ Info  ] downloading: https://raw.githubusercontent.com/haskell/ghcup-metadata/master/ghcup-0.0.7.yaml as file /home/xxx/.ghcup/cache/ghcup-0.0.7.yaml
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
[ Info  ] Upgrading GHCup...
[ Warn  ] No GHCup update available

System requirements
  Please ensure the following distro packages are installed before continuing (you can exit ghcup and return at any time): curl gcc gmp gmake ncurses perl5 libffi libiconv
Press ENTER to proceed or ctrl-c to abort.
Installation may take a while.


[ Info  ] downloading: https://downloads.haskell.org/~ghc/8.10.7/ghc-8.10.7-x86_64-unknown-freebsd.tar.xz as file /home/xxx/.ghcup/cache/ghc-8.10.7-x86_64-unknown-freebsd.tar.xz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  170M  100  170M    0     0  25.8M      0  0:00:06  0:00:06 --:--:-- 29.1M
[ Info  ] verifying digest of: ghc-8.10.7-x86_64-unknown-freebsd.tar.xz
[ Info  ] Unpacking: ghc-8.10.7-x86_64-unknown-freebsd.tar.xz to /home/xxx/.ghcup/tmp/ghcup-3d60f2a266d90484
[ Info  ] Installing GHC (this may take a while)
[ Info  ] Merging file tree from "/home/xxx/.ghcup/tmp/ghcup-55050b90ee2b4e29/home/xxx/.ghcup/ghc/8.10.7" to "/home/xxx/.ghcup/ghc/8.10.7"
[ Info  ] GHC installation successful
[ Info  ] GHC 8.10.7 successfully set as default version
[ Info  ] downloading: https://downloads.haskell.org/~cabal/cabal-install-3.6.2.0/cabal-install-3.6.2.0-x86_64-freebsd13.tar.xz as file /home/xxx/.ghcup/cache/cabal-install-3.6.2.0-x86_64-freebsd13.tar.xz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 5923k  100 5923k    0     0  17.0M      0 --:--:-- --:--:-- --:--:-- 17.0M
[ Info  ] verifying digest of: cabal-install-3.6.2.0-x86_64-freebsd13.tar.xz
[ Info  ] Unpacking: cabal-install-3.6.2.0-x86_64-freebsd13.tar.xz to /home/xxx/.ghcup/tmp/ghcup-3e36172017b03fd1
[ Info  ] Installing cabal
[ Info  ] Cabal installation successful
Config file path source is default config file.
Config file /home/xxx/.cabal/config not found.
Writing default configuration to /home/xxx/.cabal/config
Downloading the latest package list from hackage.haskell.org
Updated package list of hackage.haskell.org to the index-state 2022-09-11T10:29:54Z
[ Warn  ] stack-2.7.5 is already installed; if you really want to reinstall it, you may want to run 'ghcup install cabal --force 2.7.5'

===============================================================================

OK! /home/xxx/.bashrc has been modified. Restart your terminal for the changes to take effect,
or type "source /home/xxx/.ghcup/env" to apply them in your current terminal session.

===============================================================================

All done!

To start a simple repl, run:
  ghci

To start a new haskell project in the current directory, run:
  cabal init --interactive

To install other GHC versions and tools, run:
  ghcup tui

If you are new to Haskell, check out https://www.haskell.org/ghcup/steps/
$ echo 'export PATH=$HOME/.local/bin:$PATH' >>~/.bashrc
$ exec -l $SHELL
$ ghcup tui
┌────────────────────────────────GHCup────────────────────────────────┐
│    Tool  Version         Tags                          Notes        │
│─────────────────────────────────────────────────────────────────────│
│✔✔  GHCup 0.1.18.0        latest,recommended                         │
│─────────────────────────────────────────────────────────────────────│
│✔✔  Stack 2.7.5           latest,recommended                         │
│─────────────────────────────────────────────────────────────────────│
│✗   HLS   1.7.0.0         latest,recommended                         │
│─────────────────────────────────────────────────────────────────────│
│✗   cabal 3.8.1.0         latest                                     │
│✔✔  cabal 3.6.2.0         recommended                                │
│─────────────────────────────────────────────────────────────────────│
│✗   GHC   9.4.2           latest,base-4.17.0.0                       │
│✗   GHC   9.2.4           base-4.16.3.0                              │
│✗   GHC   9.0.2           base-4.15.1.0                              │
│✔✔  GHC   8.10.7          recommended,base-4.14.3.0                  │
│✗   GHC   8.8.4           base-4.13.0.0                              │
│✗   GHC   8.6.5           base-4.12.0.0                              │
│✗   GHC   8.4.4           base-4.11.1.0                              │
└─────────────────────────────────────────────────────────────────────┘
q:Quit  i:Install  u:Uninstall  s:Set  c:ChangeLog  a:Show all versions
t:Show all tools  ↑:Up  ↓:Down
q
$ stack new hoge
...
$ cd hoge
$ stack build
...
$ stack run
someFunc
$

問題なく動作しているようです。

インストール途中に以下のメッセージが表示されましたが、私の環境にはすべて揃っていました。

System requirements
  Please ensure the following distro packages are installed before continuing (you can exit ghcup and return at any time): curl gcc gmp gmake ncurses perl5 libffi libiconv