Pretty-printing – Haskell – Aelve Guidehttps://guide.aelve.com/haskell/feed/category/uhierj0c2018-08-14T13:25:22Zr7fq4cvrpretty-simple2018-08-14T13:25:22Z<h1> <span class="item-name">pretty-simple</span>
(<a href="https://hackage.haskell.org/package/pretty-simple">Hackage</a>)
</h1><p><code>pretty-simple</code> is a pretty printer for Haskell data types that have a Show instance.</p>
<h2>Pros</h2><ul><p><li>can turn deriving(Show) into something readable automatically</li></p><p><li>includes a drop-in replacement for Debug.Trace</li></p></ul><h2>Cons</h2><ul><p><li>more limited than prettyprinter if you intend to write your own printers</li></p></ul>g3bsxslpprettyprinter2017-09-27T20:43:00Z<h1> <a href="https://github.com/quchen/prettyprinter" class="item-name">prettyprinter</a>
(<a href="https://hackage.haskell.org/package/prettyprinter">Hackage</a>)
</h1><p>Pretty printer loosely based on Wadler's <a href="https://homepages.inf.ed.ac.uk/wadler/papers/prettier/prettier.pdf">"A Prettier Printer"</a> paper.</p>
<p><strong>Example</strong></p>
<div class="sourceCode"><pre class="sourceCode"><code class="sourceCode"><span class="kw">let</span> prettyType <span class="fu">=</span> align <span class="fu">.</span> sep <span class="fu">.</span> zipWith (<span class="fu"><+></span>) (<span class="st">"::"</span> <span class="fu">:</span> repeat <span class="st">"->"</span>)
prettySig name ty <span class="fu">=</span> pretty name <span class="fu"><+></span> prettyType ty
<span class="kw">in</span> prettySig <span class="st">"example"</span> [<span class="st">"Int"</span>, <span class="st">"Bool"</span>, <span class="st">"Char"</span>, <span class="st">"IO ()"</span>]</code></pre></div>
<div class="sourceCode"><pre class="sourceCode"><code class="sourceCode"><span class="co">-- Output for wide enough formats:</span>
<span class="ot">example ::</span> <span class="dt">Int</span> <span class="ot">-></span> <span class="dt">Bool</span> <span class="ot">-></span> <span class="dt">Char</span> <span class="ot">-></span> <span class="dt">IO</span> ()
<span class="co">-- Output for narrow formats:</span>
<span class="ot">example ::</span> <span class="dt">Int</span>
<span class="ot">-></span> <span class="dt">Bool</span>
<span class="ot">-></span> <span class="dt">Char</span>
<span class="ot">-></span> <span class="dt">IO</span> ()</code></pre></div>
<h2>Pros</h2><ul><p><li>Uses <code>Text</code> instead of <code>String</code> for better performance</li></p><p><li>Supports annotations (coloring, mouse-over hovers, adding URLs, etc.)</li></p><p><li>Excellent <a href="https://hackage.haskell.org/package/prettyprinter-1.1.1/docs/Data-Text-Prettyprint-Doc.html">docs</a> and <a href="https://github.com/quchen/prettyprinter/tree/master/prettyprinter/src/Data/Text/Prettyprint/Doc/Render/Tutorials">tutorial</a></li></p><p><li>Has <code>compat</code> packages to help migrate from other pretty printing libraries</li></p></ul><h2>Cons</h2><ul></ul><h2>Ecosystem</h2><ul>
<li><a href="https://hackage.haskell.org/package/prettyprinter">prettyprinter</a> - the core package</li>
<li><a href="https://hackage.haskell.org/package/prettyprinter-ansi-terminal">prettyprinter-ansi-terminal</a> - a renderer suitable for ANSI terminal output including colors</li>
<li><a href="https://hackage.haskell.org/package/prettyprinter-compat-wl-pprint">prettyprinter-compat-wl-pprint</a> a drop-in compatibility layer for previous users of <code>wl-pprint</code></li>
<li><a href="https://hackage.haskell.org/package/prettyprinter-compat-ansi-wl-pprint">prettyprinter-compat-ansi-wl-pprint</a> - the same, but for previous users of <code>ansi-wl-pprint</code></li>
<li><a href="https://hackage.haskell.org/package/prettyprinter-compat-annotated-wl-pprint">prettyprinter-compat-annotated-wl-pprint</a> - the same, but for previous users of <code>annotated-wl-pprint</code></li>
<li><a href="https://hackage.haskell.org/package/prettyprinter-convert-ansi-wl-pprint">prettyprinter-convert-ansi-wl-pprint</a> - a converter, not a drop-in replacement, for documents generated by <code>ansi-wl-pprint</code></li>
</ul>
<p>See <a href="https://github.com/quchen/prettyprinter/blob/master/README.md#the-prettyprinter-family">the README</a> for more information.</p>
atkyw60jpretty2016-07-11T09:28:17Z<h1> <span class="item-name">pretty</span>
(<a href="https://hackage.haskell.org/package/pretty">Hackage</a>)
</h1><p>Pretty printer based on John Hughes' <a href="http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.38.8777">"The Design of a Pretty-printing Library"</a> paper and improved by Simon Peyton Jones.</p>
<h2>Pros</h2><ul><p><li>Few dependencies (and all of them ship with GHC)</li></p></ul><h2>Cons</h2><ul><p><li>Uses <code>String</code> instead of <a href="https://hackage.haskell.org/package/text">text</a> which causes poor performance when formatting a large amount of output</li></p></ul>pv0594vcboxes2016-07-11T09:28:08Z<h1> <span class="item-name">boxes</span>
(<a href="https://hackage.haskell.org/package/boxes">Hackage</a>)
</h1><p>Lays out text in two dimensions, using a simple box model.</p>
<p><strong>Example</strong></p>
<div class="sourceCode"><pre class="sourceCode"><code class="sourceCode"><span class="ot">print_table ::</span> [[<span class="dt">String</span>]] <span class="ot">-></span> <span class="dt">IO</span> ()
print_table rows <span class="fu">=</span> printBox <span class="fu">$</span> hsep <span class="dv">2</span> left (map (vcat left <span class="fu">.</span> map text) (transpose rows))</code></pre></div>
<div class="sourceCode"><pre class="sourceCode"><code class="sourceCode">Mercoxit 335.67
Arkonor 276.15
Bistot 214.30</code></pre></div>
<p><a href="http://www.tedreed.info/programming/2012/06/02/how-to-use-textprettyprintboxes/">Source</a></p>
<h2>Pros</h2><ul><p><li>Few dependencies (<a href="https://hackage.haskell.org/package/base">base</a> and <a href="https://hackage.haskell.org/package/split">split</a>)</li></p><p><li>Simple model</li></p></ul><h2>Cons</h2><ul><p><li>Limited formatting configuration</li></p><p><li>No examples/tutorial</li></p></ul>