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+<h1 class="title">Advent of Code 2020</h1>
+</header>
+<p>Code to solve the <a href="http://adventofcode.com/2020/">Advent of Code</a> puzzles. This year, I’m using the puzzles to develop my skills in <a href="https://wiki.haskell.org/Haskell">Haskell</a>. I’m writing up a <a href="https://work.njae.me.uk/tag/advent-of-code/">commentary on these puzzles and my solutions</a> on my blog.</p>
+<p><a href="http://learnyouahaskell.com/chapters">Learn you a Haskell</a>, <a href="https://www.haskell.org/tutorial/index.html">Introduction to Haskell 98</a>, and <a href="https://hackage.haskell.org/">Hackage</a> are good resources.</p>
+<p>The <a href="https://cabal.readthedocs.io/en/latest/index.html">Cabal user guide</a> and <a href="http://howistart.org/posts/haskell/1/">How I Start: Haskell</a> are good sources of using the tools.</p>
+<h1 id="toolchain">Toolchain</h1>
+<p>Install Ghcup following <a href="https://www.haskell.org/ghcup/install/#installation">the instructions</a>, making sure to load the updated environment with</p>
+<div class="sourceCode" id="cb1"><pre class="sourceCode bash"><code class="sourceCode bash"><span id="cb1-1"><a href="#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="bu">source</span> /home/neil/.ghcup/env</span></code></pre></div>
+<p>and then set the default GHC to use with <code>ghcup set ghc 9.0.1</code> .</p>
+<p>Install <a href="https://haskell-language-server.readthedocs.io/en/latest/configuration.html">Haskell Language Server</a> for Sublime Text</p>
+<h2 id="creating-the-repository-and-project">Creating the repository and project</h2>
+<p>Create the repository as normal: create the project in Gitolite, clone it, and insert the <code>.gitignore</code> and <code>README.md</code> files.</p>
+<p>There’s one package per day, with the code for each package in sub-directories of the root directory.</p>
+<p>Create the basic <code>cabal</code> project.</p>
+<pre><code>cabal init</code></pre>
+<p>Modify the <code>advent-of-code21.cabal</code> file as needed, such as updating the Cabal version and writing the <code>common</code> stanzas.</p>
+<h2 id="creating-subsequent-days">Creating subsequent days</h2>
+<p>Each day lives in a separate directory, with code in the <code>src</code> directory.</p>
+<p>Compile with</p>
+<pre><code>cabal build</code></pre>
+<p>or</p>
+<pre><code>cabal build advent01</code></pre>
+<p>Run with</p>
+<pre><code>cabal run advent01</code></pre>
+<p>If you want to pass in additional RTS parameters, do it like this:</p>
+<pre><code>cabal run advent01 -- +RTS -K0 -RTS</code></pre>
+<p>Run interactively with</p>
+<pre><code>cabal repl advent01</code></pre>
+<p>or</p>
+<pre><code>stack ghci advent01:exe:advent01</code></pre>
+<p>if the first form is ambiguous.</p>
+<p>To profile, use</p>
+<pre><code>cabal run advent01 --enable-profiling -- +RTS -N -p -s -hT</code></pre>
+<p>Or, you can simplify the RTS options by adding them to a new stanza in the cabal file:</p>
+<pre><code>executable advent01prof
+ import: common-extensions, build-directives
+ main-is: advent01/Main.hs
+ build-depends: text, containers, linear, array, pqueue, mtl, lens
+ ghc-options: -O2
+ -Wall
+ -threaded
+ -rtsopts "-with-rtsopts=-N -p -s -hT"</code></pre>
+<p>then running</p>
+<pre><code>cabal run advent01prof --enable-profiling</code></pre>
+<p>Generate the profile graph with</p>
+<pre><code>hp2ps -M advent01.hp</code></pre>
+<p>For Cabal, look at <a href="https://nikita-volkov.github.io/profiling-cabal-projects/">profiling with Cabal sandboxes</a></p>
+<h1 id="packages">Packages</h1>
+<p>Packages I used a lot:</p>
+<ul>
+<li><a href="https://hackage.haskell.org/package/containers">Containers</a> (and some <a href="https://haskell-containers.readthedocs.io/en/latest/intro.html">better documentation</a>); <a href="https://hackage.haskell.org/package/unordered-containers">Unordered containers</a> is a mostly-equivalent alternative.</li>
+<li><a href="https://hackage.haskell.org/package/attoparsec">Attoparsec</a> (and <a href="https://hackage.haskell.org/package/megaparsec">Megaparsec</a>, and <a href="https://hackage.haskell.org/package/base-4.14.1.0/docs/Text-ParserCombinators-ReadP.html">ReadP</a> once).</li>
+</ul>
+<p>There are somewhat decent <a href="https://markkarpov.com/tutorial/megaparsec.html">tutorials on Megaparsec</a> and <a href="https://www.schoolofhaskell.com/school/starting-with-haskell/libraries-and-frameworks/text-manipulation/attoparsec">Attoparsec</a>.</p>
+<p>Packages I didn’t use much, but need to remember:</p>
+<ul>
+<li><a href="https://hackage.haskell.org/package/arithmoi">Arithmoi</a> for number theory</li>
+<li><a href="https://hackage.haskell.org/package/pointedlist-0.6.1">Pointed List</a> for zipper lists (sometimes circular)</li>
+<li><a href="https://hackage.haskell.org/package/vector">Vector</a> for array-like things</li>
+<li><a href="https://hackage.haskell.org/package/linear">Linear</a> for coordinate-vector like things</li>
+<li><a href="https://hackage.haskell.org/package/grid">Grid</a> for 2-d grids</li>
+<li><a href="https://hackage.haskell.org/package/graph-wrapper">Graph-wrapper</a> for graphs</li>
+<li><a href="https://hackage.haskell.org/package/lens">Lens</a> (and a <a href="https://github.com/ekmett/lens/wiki/Operators">summary of operators</a>). I didn’t use these much this year, but did a lot last year.</li>
+<li><a href="https://hackage.haskell.org/package/mtl-2.2.2/docs/Control-Monad-RWS-Lazy.html">RWS</a> (Reader-Writer-State monad stack); again, used a lot last year but not this year</li>
+<li><a href="https://hackage.haskell.org/package/monad-loops-0.4.3/docs/Control-Monad-Loops.html">Monad loops</a>, and <a href="https://conscientiousprogrammer.com/blog/2015/12/11/24-days-of-hackage-2015-day-11-monad-loops-avoiding-writing-recursive-functions-by-refactoring/">a description</a></li>
+<li><a href="https://github.com/jamesdbrock/replace-megaparsec">Replace-Megaparsec</a>, for using Mpc for all sorts of things traditionally done with regex substitutions.</li>
+</ul>
+<h1 id="readme">Readme</h1>
+<p>Build this readme file wth</p>
+<pre><code>pandoc -s README.md > README.html</code></pre>
+<p>(Using the <a href="https://github.com/markdowncss/modest">Modest style</a>.)</p>
+</body>
+</html>
[Learn you a Haskell](http://learnyouahaskell.com/chapters), [Introduction to Haskell 98](https://www.haskell.org/tutorial/index.html), and [Hackage](https://hackage.haskell.org/) are good resources.
-The [Stack documentation](https://docs.haskellstack.org/en/stable/README/) and [How I Start: Haskell](http://howistart.org/posts/haskell/1/) are good sources of using the tools.
-
+The [Cabal user guide](https://cabal.readthedocs.io/en/latest/index.html) and [How I Start: Haskell](http://howistart.org/posts/haskell/1/) are good sources of using the tools.
# Toolchain
## Creating subsequent days
-Each day lives in a separate directory, with its own `package.yaml` file and code in the `src` directory. (I based this configuration from [mstksg's setup](https://github.com/mstksg/advent-of-code-2018).)
+Each day lives in a separate directory, with code in the `src` directory.
Compile with
```
If you want to pass in additional RTS parameters, do it like this:
```
-stack exec -- advent01 +RTS -K0 -RTS
+cabal run advent01 -- +RTS -K0 -RTS
```
Run interactively with
if the first form is ambiguous.
To profile, use
+
```
-stack build --executable-profiling --library-profiling --ghc-options="-fprof-auto -rtsopts" advent01
+cabal run advent01 --enable-profiling -- +RTS -N -p -s -hT
```
-then run with
+
+Or, you can simplify the RTS options by adding them to a new stanza in the cabal file:
+
```
-stack exec --profile -- advent01 +RTS -p -hy
+executable advent01prof
+ import: common-extensions, build-directives
+ main-is: advent01/Main.hs
+ build-depends: text, containers, linear, array, pqueue, mtl, lens
+ ghc-options: -O2
+ -Wall
+ -threaded
+ -rtsopts "-with-rtsopts=-N -p -s -hT"
```
+
+then running
+
+```
+cabal run advent01prof --enable-profiling
+```
+
+
Generate the profile graph with
```
-stack exec hp2ps advent01.hp
+hp2ps -M advent01.hp
```
For Cabal, look at [profiling with Cabal sandboxes](https://nikita-volkov.github.io/profiling-cabal-projects/)
# Packages
-Stack is using the [14.16-lts resolver](https://www.stackage.org/lts-16.25) for packages, so make sure you read the [correct documentation for the packages included in it](https://www.stackage.org/lts-16.25/docs).
-
Packages I used a lot:
* [Containers](https://hackage.haskell.org/package/containers) (and some [better documentation](https://haskell-containers.readthedocs.io/en/latest/intro.html)); [Unordered containers](https://hackage.haskell.org/package/unordered-containers) is a mostly-equivalent alternative.
type CaveContext = Reader Cave
-
data Agendum s =
Agendum { _current :: s
, _trail :: Q.Seq s
class (Eq s, Ord s, Show s) => SearchState s where
unwrapPos :: s -> BasePosition
+ emptySearchState :: s
successors :: s -> CaveContext (Q.Seq s)
estimateCost :: s -> CaveContext Int
- emptySearchState :: s
isGoal :: s -> CaveContext Bool
entryCost :: s -> CaveContext Int
emptySearchState = Position (V2 0 0)
-- successors :: Position -> CaveContext (Q.Seq Position)
- successors here =
+ successors (Position here) =
do grid <- asks _grid
let neighbours =
filter (inRange (bounds grid))
- [ (unwrapPos here) ^+^ delta
+ [ here ^+^ delta
| delta <- [V2 -1 0, V2 1 0, V2 0 -1, V2 0 1]
]
let succs = Q.fromList $ map Position neighbours
return succs
-- estimateCost :: Position -> CaveContext Int
- estimateCost here =
+ estimateCost (Position here) =
do goal <- asks _goal
- let (V2 dr dc) = (unwrapPos here) ^-^ goal
+ let (V2 dr dc) = here ^-^ goal
return $ (abs dr) + (abs dc)
-- isGoal :: here -> CaveContext Bool
- isGoal here =
+ isGoal (Position here) =
do goal <- asks _goal
- return $ (unwrapPos here) == goal
+ return $ here == goal
- entryCost here =
+ entryCost (Position here) =
do grid <- asks _grid
- return $ grid ! (unwrapPos here)
+ return $ grid ! here
instance SearchState TiledPosition where
- emptySearchState = TiledPosition (V2 0 0)
-
unwrapPos (TiledPosition p) = p
+ emptySearchState = TiledPosition (V2 0 0)
+
-- successors :: Position -> CaveContext (Q.Seq Position)
successors (TiledPosition here) =
do grid <- asks _grid
projects / advent-of-code-21.git / commitdiff