commit 52e52ba036b5d0cba128a5f5b99c7232b0270b86
Author: davidalst <david@alst-it.de>
Date:   Sun Jun 16 21:29:40 2024 +0200

    first commit

diff --git a/.DS_Store b/.DS_Store
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index 0000000..61ebb7a
Binary files /dev/null and b/.DS_Store differ
diff --git a/.devcontainer/.ghci b/.devcontainer/.ghci
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index 0000000..ce42ab8
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+++ b/.devcontainer/.ghci
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+:set prompt "\ESC[94m\STX  \ESC[m\STX"
+:set prompt-cont "\ESC[1;32mλ| \ESC[m"
+:set +t
+:set +m
+:set +s
+
+:set editor emacs
+
+:set -Wall
+:set -ferror-spans
+:set -freverse-errors
+:set -fprint-expanded-synonyms
+:set -fprint-explicit-foralls
+:set -fprint-explicit-kinds
+:set -ignore-package pretty-simple -package pretty-simple
+-- :set -fobject-code
+
+:seti -XFlexibleContexts
+:seti -XFlexibleInstances
+:seti -XOverloadedStrings
+:seti -XGADTSyntax
+:seti -XGeneralizedNewtypeDeriving
+:seti -XInstanceSigs
+:seti -XLambdaCase
+:seti -XPartialTypeSignatures
+:seti -XScopedTypeVariables
+:seti -XPolyKinds
+:seti -XDataKinds
+:seti -XTypeApplications
+:seti -XTypeApplications
+
+:def hlint const . return $ ":! hlint \"src\""
+:def hoogle \s -> return $ ":! hoogle --count=15 \"" ++ s ++ "\""
+:def package \ m -> return $ ":! ghc-pkg --simple-output find-module " ++ m
\ No newline at end of file
diff --git a/.devcontainer/Dockerfile b/.devcontainer/Dockerfile
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--- /dev/null
+++ b/.devcontainer/Dockerfile
@@ -0,0 +1,105 @@
+FROM debian:bookworm-slim as base
+
+ENV LANG C.UTF-8
+
+ARG GHC_VERSION=9.6.3
+ARG STACK_VERSION=recommended
+ARG STACK_RESOLVER=lts-22.6
+ARG CABAL_VERSION=recommended
+ARG HLS_VERSION=recommended
+ARG LLVM_VERSION=17
+
+ENV USERNAME=vscode \
+    USER_UID=1000 \
+    USER_GID=1000 \
+    DEBIAN_FRONTEND=noninteractive \
+    GHC_VERSION=${GHC_VERSION} \
+    STACK_VERSION=${STACK_VERSION} \
+    STACK_RESOLVER=${STACK_RESOLVER} \
+    CABAL_VERSION=${CABAL_VERSION} \
+    HLS_VERSION=${HLS_VERSION} \
+    LLVM_VERSION=${LLVM_VERSION}
+
+RUN ulimit -n 8192
+
+RUN VERSION_CODENAME=$(grep VERSION_CODENAME /etc/os-release | cut -d'=' -f2) && \
+    apt-get update && \
+    apt-get install -y --no-install-recommends software-properties-common wget && \
+    # I don't know why, nor do I have any mental capacity to figure it out,
+    # but we need to add the repository twice, otherwise it doesn't work (repo isn't being added)
+    add-apt-repository -y -s -n "deb http://apt.llvm.org/${VERSION_CODENAME}/ llvm-toolchain-${VERSION_CODENAME}-${LLVM_VERSION} main" && \
+    add-apt-repository -y -s -n "deb http://apt.llvm.org/${VERSION_CODENAME}/ llvm-toolchain-${VERSION_CODENAME}-${LLVM_VERSION} main" && \
+    wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc && \
+    apt-get update && \
+    apt-get install -y --no-install-recommends apt-utils bash build-essential ca-certificates curl gcc git gnupg libffi-dev libffi8 libgmp-dev libgmp-dev libgmp10 libicu-dev libncurses-dev libncurses5 libnuma1 libnuma-dev libtinfo5 lsb-release make procps sudo xz-utils z3 zlib1g-dev clang-$LLVM_VERSION lldb-$LLVM_VERSION lld-$LLVM_VERSION clangd-$LLVM_VERSION
+
+RUN groupadd --gid ${USER_GID} ${USERNAME} && \
+    useradd -ms /bin/bash -K MAIL_DIR=/dev/null --uid ${USER_UID} --gid ${USER_GID} -m ${USERNAME} && \
+    echo ${USERNAME} ALL=\(root\) NOPASSWD:ALL > /etc/sudoers.d/${USERNAME} && \
+    chmod 0440 /etc/sudoers.d/${USERNAME}
+
+USER ${USER_UID}:${USER_GID}
+WORKDIR /home/${USERNAME}
+ENV PATH="/home/${USERNAME}/.local/bin:/home/${USERNAME}/.cabal/bin:/home/${USERNAME}/.ghcup/bin:$PATH"
+
+RUN echo "export PATH=${PATH}" >> /home/${USERNAME}/.profile
+
+ENV BOOTSTRAP_HASKELL_NONINTERACTIVE=yes \
+    BOOTSTRAP_HASKELL_NO_UPGRADE=yes
+
+FROM base as tooling
+
+RUN curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh
+
+# Set the GHC version.
+RUN ghcup install ghc ${GHC_VERSION} --set
+
+# Install cabal-iinstall
+RUN ghcup install cabal ${CABAL_VERSION} --set
+
+# Update Cabal.
+RUN cabal update && cabal new-install cabal-install
+
+# Configure cabal
+RUN cabal user-config update -f && \
+    sed -i 's/-- ghc-options:/ghc-options: -haddock/g' ~/.cabal/config
+
+# Install stack
+RUN ghcup install stack ${STACK_VERSION} --set
+
+# Set system-ghc, install-ghc and resolver for stack.
+RUN ((stack ghc -- --version 2>/dev/null) || true) && \
+    # Set global defaults for stack.
+    stack config --system-ghc set system-ghc true --global && \
+    stack config --system-ghc set install-ghc false --global && \
+    stack config --system-ghc set resolver ${STACK_RESOLVER}
+
+# Set global custom defaults for stack.
+RUN printf "ghc-options:\n  \"\$everything\": -haddock\n" >> /home/${USERNAME}/.stack/config.yaml
+
+# Install hls
+RUN ghcup install hls ${HLS_VERSION} --set
+
+FROM tooling as packages
+
+# Install global packages.
+# Versions are pinned, since we don't want to accidentally break anything (by always installing latest).
+RUN cabal install --haddock-hoogle --minimize-conflict-set \
+    fsnotify \
+    haskell-dap \
+    ghci-dap \
+    haskell-debug-adapter \
+    hlint \
+    apply-refact \
+    retrie \
+    hoogle \
+    ormolu
+
+FROM packages as hoogle
+
+# Generate hoogle db
+RUN hoogle generate --download --haskell
+
+ENV DEBIAN_FRONTEND=dialog
+
+ENTRYPOINT ["/bin/bash"]
diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
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--- /dev/null
+++ b/.devcontainer/devcontainer.json
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+{
+  "name": "DevContainer for Haskell (GHC, Stack, Cabal, HIE, LSP, DAP, etc.)",
+  "remoteUser": "vscode",
+  "runArgs": [],
+  "build": {
+    "args": {
+      "USERNAME": "vscode",
+      "GHC_VERSION": "9.6.3",
+      "STACK_VERSION": "recommended",
+      "STACK_RESOLVER": "lts-22.6",
+      "CABAL_VERSION": "recommended",
+      "HLS_VERSION": "recommended",
+      "LLVM_VERSION": "17"
+    },
+    "context": "..",
+    "dockerfile": "Dockerfile"
+  },
+  "customizations": {
+    "vscode": {
+      "extensions": [
+        "haskell.haskell",
+        "phoityne.phoityne-vscode",
+        "eriksik2.vscode-ghci",
+        "jcanero.hoogle-vscode"
+      ],
+      "settings": {
+        "files.exclude": {
+          "**/*.olean": true,
+          "**/.DS_Store": true,
+          "**/.git": true,
+          "**/.hg": true,
+          "**/.svn": true,
+          "**/CVS": true
+        },
+        "haskell.checkProject": true,
+        "haskell.formattingProvider": "ormolu",
+        "haskell.indentationRules.enabled": true,
+        "haskell.liquidOn": false,
+        "haskell.checkParents": "CheckOnSave",
+        "haskell.manageHLS": "GHCup",
+        "haskell.maxCompletions": 40,
+        "haskell.openDocumentationInHackage": false,
+        "haskell.openSourceInHackage": false,
+        "haskell.trace.client": "error",
+        "haskell.trace.server": "off",
+        "haskell.upgradeGHCup": true,
+        "hoogle-vscode.useCabalDependencies": true
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/.vscode/tasks.json b/.vscode/tasks.json
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+++ b/.vscode/tasks.json
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+
+{
+  // Automatically created by phoityne-vscode extension.
+
+  "version": "2.0.0",
+  "presentation": {
+    "reveal": "always",
+    "panel": "new"
+  },
+  "tasks": [
+    {
+      // F7
+      "group": {
+        "kind": "build",
+        "isDefault": true
+      },
+      "label": "haskell build",
+      "type": "shell",
+      //"command": "cabal configure && cabal build"
+      "command": "stack build"
+    },
+    {
+      // F6
+      "group": "build",
+      "type": "shell",
+      "label": "haskell clean & build",
+      //"command": "cabal clean && cabal configure && cabal build"
+      "command": "stack clean && stack build"
+      //"command": "stack clean ; stack build"  // for powershell
+    },
+    {
+      // F8
+      "group": {
+        "kind": "test",
+        "isDefault": true
+      },
+      "type": "shell",
+      "label": "haskell test",
+      //"command": "cabal test"
+      "command": "stack test"
+    },
+    {
+      // F6
+      "isBackground": true,
+      "type": "shell",
+      "label": "haskell watch",
+      "command": "stack build --test --no-run-tests --file-watch"
+    }
+  ]
+}
diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020 Igal Tabachnik
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/README.md b/README.md
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+++ b/README.md
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+# A (highly opinionated) Docker image for Haskell development
+
+**Note**: The way this container setup is very opinionaed, you may want to check out [an official dev containter for Haskell](https://github.com/microsoft/vscode-dev-containers/tree/main/containers/haskell).
+
+<!-- markdown-toc start - Don't edit this section. Run M-x markdown-toc-refresh-toc -->
+**Table of Contents**
+
+- [A (highly opinionated) Docker image for Haskell development](#a-highly-opinionated-docker-image-for-haskell-development)
+  - [Visual Studio Code: DevContainer for Haskell](#visual-studio-code-devcontainer-for-haskell)
+    - [What is this](#what-is-this)
+    - [How to use this](#how-to-use-this)
+    - [How does it work](#how-does-it-work)
+  - [What's in the box](#whats-in-the-box)
+    - [How to build locally](#how-to-build-locally)
+
+<!-- markdown-toc end -->
+
+## Visual Studio Code: DevContainer for Haskell
+
+### What is this
+
+This is a DevContainer <sup>[[1](https://code.visualstudio.com/docs/remote/containers)][[2](https://code.visualstudio.com/docs/remote/containers-advanced)]</sup> environment for Visual Studio Code, allowing automatically installing the Haskell compiler (GHC), Stack, Cabal, HLS (Haskell Language Server), and the necessary Visual Studio Code extensions to set up a Haskell development environment with zero additional effort.
+
+**Note**: For debugging support, please refer to [Haskell GHCi Debugger Adapter Phoityne](https://marketplace.visualstudio.com/items?itemName=phoityne.phoityne-vscode) extension documentation.
+
+### How to use this
+
+Follow the [Getting Started](https://code.visualstudio.com/docs/remote/containers#_getting-started) instructions to configure your Visual Studio Code and Docker to use with DevContainers.
+
+Place the `.devcontainer` directory in the root of your project, and the next time you load the project, Visual Studio Code will prompt to re-open the project in a container:
+
+![image](https://user-images.githubusercontent.com/601206/73298150-7bfac580-4215-11ea-81d3-a8fabab98e30.png)
+
+**Note**: building the container might take a few minutes until all dependencies have finished downloading and installing.
+
+### How does it work
+
+Visual Studio Code supports [Developing inside a Container](https://code.visualstudio.com/docs/remote/containers) - using a Docker image as a development environment. It automates the process of creating the container image, as well as installing additional required extensions into the editor.
+
+Pressing **Reopen in Container** will perform the automated steps to launch the container, and set up the environment.
+
+For more information and setup, read the official documentation: <https://code.visualstudio.com/docs/remote/containers> and <https://code.visualstudio.com/docs/remote/containers-advanced>
+
+## What's in the box
+
+[`.devcontainer/Dockerfile`](.devcontainer/Dockerfile) DevContainer Docker image.
+
+[`debian:bullseye`](https://hub.docker.com/_/debian) as a base image.
+
+Additional software installed:
+
+- Glasgow Haskell Compiler (GHC) via [ghcup](https://www.haskell.org/ghcup/).
+- A Haskell LSP server HLS - ([haskell-language-server](https://github.com/haskell/haskell-language-server)).
+- [Stack](https://docs.haskellstack.org/en/stable/README/).
+- [Cabal](https://www.haskell.org/cabal/).
+- Following Debian packages: `apt-utils bash build-essential ca-certificates curl gcc git gnupg libffi-dev libffi7 libgmp-dev libgmp-dev libgmp10 libicu-dev libncurses-dev libncurses5 libnuma1 libnuma-dev libtinfo5 lsb-release make procps software-properties-common sudo wget xz-utils z3 zlib1g-dev`.
+- Following Haskell packages (via [cabal](https://nixos.org/nixos/packages.html)): `haskell-dap ghci-dap haskell-debug-adapter hlint apply-refact retrie stylish-haskell hoogle ormolu liquidhaskell`.
+- LLVM 12 via [LLVM Automatic installation script](https://apt.llvm.org/).
+
+**NOTE:** *When changing GHC/HLS versions, please refer to the [GHC/HLS compatibility table](https://haskell-language-server.readthedocs.io/en/latest/supported-versions.html).*
+
+Following VSCode extensions are installed after container is started:
+
+- [Haskell extension](https://marketplace.visualstudio.com/items?itemName=haskell.haskell).
+- [Haskell GHCi Debugger Adapter](https://marketplace.visualstudio.com/items?itemName=phoityne.phoityne-vscode).
+- [Integrated Haskell Shell](https://marketplace.visualstudio.com/items?itemName=eriksik2.vscode-ghci).
+- [Hoogle for VSCode](https://marketplace.visualstudio.com/items?itemName=jcanero.hoogle-vscode).
+
+The [`devcontainer.json`](.devcontainer/devcontainer.json) has some additional configuration for VSCode, in particular, the required extensions that have to be installed, the name of the remote user (must match the one in the [`Dockerfile`](.devcontainer/Dockerfile)), and...⏎
+
+<details>
+<summary>... the following settings</summary>
+
+```json
+{
+    "files.exclude": {
+      "**/*.olean": true,
+      "**/.DS_Store": true,
+      "**/.git": true,
+      "**/.hg": true,
+      "**/.svn": true,
+      "**/CVS": true
+    },
+    "haskell.checkProject": true,
+    "haskell.formattingProvider": "ormolu",
+    "haskell.indentationRules.enabled": true,
+    "haskell.liquidOn": true,
+    "haskell.manageHLS": "GHCup",
+    "haskell.maxCompletions": 40,
+    "haskell.openDocumentationInHackage": false,
+    "haskell.openSourceInHackage": false,
+    "haskell.plugin.alternateNumberFormat.globalOn": true,
+    "haskell.plugin.callHierarchy.globalOn": true,
+    "haskell.plugin.changeTypeSignature.globalOn": true,
+    "haskell.plugin.class.globalOn": true,
+    "haskell.plugin.eval.config.diff": true,
+    "haskell.plugin.eval.config.exception": true,
+    "haskell.plugin.eval.globalOn": true,
+    "haskell.plugin.ghcide-code-actions-bindings.globalOn": true,
+    "haskell.plugin.ghcide-code-actions-fill-holes.globalOn": true,
+    "haskell.plugin.ghcide-code-actions-imports-exports.globalOn": true,
+    "haskell.plugin.ghcide-code-actions-type-signatures.globalOn": true,
+    "haskell.plugin.ghcide-completions.config.autoExtendOn": true,
+    "haskell.plugin.ghcide-completions.config.snippetsOn": true,
+    "haskell.plugin.ghcide-completions.globalOn": true,
+    "haskell.plugin.ghcide-hover-and-symbols.hoverOn": true,
+    "haskell.plugin.ghcide-hover-and-symbols.symbolsOn": true,
+    "haskell.plugin.ghcide-type-lenses.config.mode": "always",
+    "haskell.plugin.ghcide-type-lenses.globalOn": true,
+    "haskell.plugin.haddockComments.globalOn": true,
+    "haskell.plugin.hlint.codeActionsOn": true,
+    "haskell.plugin.hlint.config.flags": [],
+    "haskell.plugin.hlint.diagnosticsOn": true,
+    "haskell.plugin.importLens.codeActionsOn": true,
+    "haskell.plugin.importLens.codeLensOn": true,
+    "haskell.plugin.moduleName.globalOn": true,
+    "haskell.plugin.pragmas.codeActionsOn": true,
+    "haskell.plugin.pragmas.completionOn": true,
+    "haskell.plugin.qualifyImportedNames.globalOn": true,
+    "haskell.plugin.refineImports.codeActionsOn": true,
+    "haskell.plugin.refineImports.codeLensOn": true,
+    "haskell.plugin.refineImports.globalOn": true,
+    "haskell.plugin.rename.config.crossModule": true,
+    "haskell.plugin.rename.globalOn": true,
+    "haskell.plugin.retrie.globalOn": true,
+    "haskell.plugin.splice.globalOn": true,
+    "haskell.plugin.tactic.config.max_use_ctor_actions": 5,
+    "haskell.plugin.tactics.codeActionsOn": true,
+    "haskell.plugin.tactics.codeLensOn": true,
+    "haskell.plugin.tactics.config.auto_gas": 4,
+    "haskell.plugin.tactics.config.hole_severity": "hint",
+    "haskell.plugin.tactics.config.max_use_ctor_actions": 5,
+    "haskell.plugin.tactics.config.proofstate_styling": true,
+    "haskell.plugin.tactics.config.timeout_duration": 5,
+    "haskell.plugin.tactics.globalOn": true,
+    "haskell.plugin.tactics.hoverOn": true,
+    "haskell.trace.client": "error",
+    "haskell.trace.server": "off",
+    "haskell.upgradeGHCup": true,
+    "hoogle-vscode.useCabalDependencies": true
+}
+```
+
+</details>
+
+This was initially based on the [DevContainer for HIE (Haskell IDE Engine)](https://github.com/hmemcpy/haskell-hie-devcontainer) by [Igal Tabachnik](https://github.com/hmemcpy).
+
+### How to build locally
+
+To build the image locally, just run `docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest` in the repository root.
+
+You can override GHC version, Cabal version, Stack resolver and HLS version by specifying `GHC_VERSION=...`, `CABAL_VERSION=...`, `STACK_RESOLVER=...` and `HLS_VERSION=...` respectively as build args.
+
+For example:
+
+- `docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest --build-arg GHC_VERSION=8.10.7`
+- `docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest --build-arg STACK_RESOLVER=lts-18.13`
+- `docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest --build-arg CABAL_VERSION=3.6.2.0`
+- `docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest --build-arg HLS_VERSION=1.5.1`
+- `docker build ./.devcontainer/ --file ./.devcontainer/Dockerfile --tag haskelldevenv:latest --build-arg GHC_VERSION=8.8.4 --build-arg STACK_RESOLVER=lts-18.13 --build-arg CABAL_VERSION=3.6.2.0 --build-arg HLS_VERSION=1.5.1`
+
+To run the image, just do `docker run --rm -it haskelldevenv:latest`.
+
+Valid values for `GHC_VERSION` can be found [here](https://www.haskell.org/ghc/download.html).
diff --git a/programs/hello b/programs/hello
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diff --git a/programs/hello.hi b/programs/hello.hi
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diff --git a/programs/hello.hs b/programs/hello.hs
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+++ b/programs/hello.hs
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+main = do
+  putStrLn "Hello, everybody!"
+  putStrLn ("Please look at my favorite odd numbers: " ++ show (filter odd [10..20]))
\ No newline at end of file
diff --git a/programs/hello.o b/programs/hello.o
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