<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="generator" content="Asciidoctor 2.0.23">
<title>PhantomType</title>
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:300,300italic,400,400italic,600,600italic%7CNoto+Serif:400,400italic,700,700italic%7CDroid+Sans+Mono:400,700">
<link rel="stylesheet" href="./asciidoctor.css">
<link rel="stylesheet" href="./mlton.css">

</head>
<body class="article">
<div id="mlton-header">
<div id="mlton-header-text">
<h2>
<a href="./Home">
MLton
20241230
</a>
</h2>
</div>
</div>
<div id="header">
<h1>PhantomType</h1>
</div>
<div id="content">
<div id="preamble">
<div class="sectionbody">
<div class="paragraph">
<p>A phantom type is a type that has no run-time representation, but is
used to force the type checker to ensure invariants at compile time.
This is done by augmenting a type with additional arguments (phantom
type variables) and expressing constraints by choosing phantom types
to stand for the phantom types in the types of values.</p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_also_see">Also see</h2>
<div class="sectionbody">
<div class="ulist">
<ul>
<li>
<p><a href="References#Blume01">Blume01</a></p>
<div class="ulist">
<ul>
<li>
<p>dimensions</p>
</li>
<li>
<p>C type system</p>
</li>
</ul>
</div>
</li>
<li>
<p><a href="References#FluetPucella06">FluetPucella06</a></p>
<div class="ulist">
<ul>
<li>
<p>subtyping</p>
</li>
</ul>
</div>
</li>
<li>
<p>socket module in <a href="BasisLibrary">Basis Library</a></p>
</li>
</ul>
</div>
</div>
</div>
</div>
<div id="mlton-footer">
<div id="mlton-footer-text">
<div>
Last updated Thu Oct 21 15:53:06 2021 -0400 by Matthew Fluet.
<a href="https://github.com/MLton/mlton/commits/master/doc/guide/src/PhantomType.adoc">Log</a>
<a href="https://github.com/MLton/mlton/edit/master/doc/guide/src/PhantomType.adoc">Edit</a>
</div>
</div>
</body>
</html>