mirror of
https://github.com/wren-lang/wren.git
synced 2026-01-11 22:28:45 +01:00
246 lines
9.3 KiB
HTML
246 lines
9.3 KiB
HTML
<!DOCTYPE html>
|
|
<html>
|
|
<head>
|
|
<meta http-equiv="Content-type" content="text/html;charset=UTF-8" />
|
|
<title>Values – Wren</title>
|
|
<script type="application/javascript" src="prism.js" data-manual></script>
|
|
<script type="application/javascript" src="codejar.js"></script>
|
|
<script type="application/javascript" src="wren.js"></script>
|
|
<link rel="stylesheet" type="text/css" href="prism.css" />
|
|
<link rel="stylesheet" type="text/css" href="style.css" />
|
|
<link href='//fonts.googleapis.com/css?family=Source+Sans+Pro:400,700,400italic,700italic|Source+Code+Pro:400|Lato:400|Sanchez:400italic,400' rel='stylesheet' type='text/css'>
|
|
<!-- Tell mobile browsers we're optimized for them and they don't need to crop
|
|
the viewport. -->
|
|
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1"/>
|
|
</head>
|
|
<body id="top">
|
|
<header>
|
|
<div class="page">
|
|
<div class="main-column">
|
|
<h1><a href="./">wren</a></h1>
|
|
<h2>a classy little scripting language</h2>
|
|
</div>
|
|
</div>
|
|
</header>
|
|
<div class="page">
|
|
<nav class="big">
|
|
<a href="./"><img src="./wren.svg" class="logo"></a>
|
|
<ul>
|
|
<li><a href="getting-started.html">Getting Started</a></li>
|
|
<li><a href="contributing.html">Contributing</a></li>
|
|
<li><a href="blog">Blog</a></li>
|
|
<li><a href="try">Try it!</a></li>
|
|
</ul>
|
|
<section>
|
|
<h2>guides</h2>
|
|
<ul>
|
|
<li><a href="syntax.html">Syntax</a></li>
|
|
<li><a href="values.html">Values</a></li>
|
|
<li><a href="lists.html">Lists</a></li>
|
|
<li><a href="maps.html">Maps</a></li>
|
|
<li><a href="method-calls.html">Method Calls</a></li>
|
|
<li><a href="control-flow.html">Control Flow</a></li>
|
|
<li><a href="variables.html">Variables</a></li>
|
|
<li><a href="functions.html">Functions</a></li>
|
|
<li><a href="classes.html">Classes</a></li>
|
|
<li><a href="concurrency.html">Concurrency</a></li>
|
|
<li><a href="error-handling.html">Error Handling</a></li>
|
|
<li><a href="modularity.html">Modularity</a></li>
|
|
</ul>
|
|
</section>
|
|
<section>
|
|
<h2>API docs</h2>
|
|
<ul>
|
|
<li><a href="modules">Modules</a></li>
|
|
</ul>
|
|
</section>
|
|
<section>
|
|
<h2>reference</h2>
|
|
<ul>
|
|
<li><a href="cli">Wren CLI</a></li>
|
|
<li><a href="embedding">Embedding</a></li>
|
|
<li><a href="performance.html">Performance</a></li>
|
|
<li><a href="qa.html">Q & A</a></li>
|
|
</ul>
|
|
</section>
|
|
</nav>
|
|
<nav class="small">
|
|
<table>
|
|
<tr>
|
|
<div><a href="getting-started.html">Getting Started</a></div>
|
|
<div><a href="contributing.html">Contributing</a></div>
|
|
<div><a href="blog">Blog</a></div>
|
|
<div><a href="try">Try it!</a></div>
|
|
</tr>
|
|
<tr>
|
|
<td colspan="2"><h2>guides</h2></td>
|
|
<td><h2>reference</h2></td>
|
|
</tr>
|
|
<tr>
|
|
<td>
|
|
<ul>
|
|
<li><a href="syntax.html">Syntax</a></li>
|
|
<li><a href="values.html">Values</a></li>
|
|
<li><a href="lists.html">Lists</a></li>
|
|
<li><a href="maps.html">Maps</a></li>
|
|
<li><a href="method-calls.html">Method Calls</a></li>
|
|
<li><a href="control-flow.html">Control Flow</a></li>
|
|
</ul>
|
|
</td>
|
|
<td>
|
|
<ul>
|
|
<li><a href="variables.html">Variables</a></li>
|
|
<li><a href="functions.html">Functions</a></li>
|
|
<li><a href="classes.html">Classes</a></li>
|
|
<li><a href="concurrency.html">Concurrency</a></li>
|
|
<li><a href="error-handling.html">Error Handling</a></li>
|
|
<li><a href="modularity.html">Modularity</a></li>
|
|
</ul>
|
|
</td>
|
|
<td>
|
|
<ul>
|
|
<li><a href="modules">API/Modules</a></li>
|
|
<li><a href="embedding">Embedding</a></li>
|
|
<li><a href="performance.html">Performance</a></li>
|
|
<li><a href="qa.html">Q & A</a></li>
|
|
</ul>
|
|
</td>
|
|
</tr>
|
|
</table>
|
|
</nav>
|
|
<main>
|
|
<h2>Values</h2>
|
|
<p>Values are the built-in atomic object types that all other objects are composed
|
|
of. They can be created through <em>literals</em>, expressions that evaluate to a
|
|
value. All values are <em>immutable</em>—once created, they do not change. The
|
|
number <code>3</code> is always the number <code>3</code>. The string <code>"frozen"</code> can never have its
|
|
character array modified in place.</p>
|
|
<h2>Booleans <a href="#booleans" name="booleans" class="header-anchor">#</a></h2>
|
|
<p>A boolean value represents truth or falsehood. There are two boolean literals,
|
|
<code>true</code> and <code>false</code>. Their class is <a href="modules/core/bool.html">Bool</a>.</p>
|
|
<h2>Numbers <a href="#numbers" name="numbers" class="header-anchor">#</a></h2>
|
|
<p>Like other scripting languages, Wren has a single numeric type:
|
|
double-precision floating point. Number literals look like you expect coming
|
|
from other languages:</p>
|
|
<pre class="snippet">
|
|
0
|
|
1234
|
|
-5678
|
|
3.14159
|
|
1.0
|
|
-12.34
|
|
0.0314159e02
|
|
0.0314159e+02
|
|
314.159e-02
|
|
</pre>
|
|
|
|
<p>Numbers are instances of the <a href="modules/core/num.html">Num</a> class.</p>
|
|
<h2>Strings <a href="#strings" name="strings" class="header-anchor">#</a></h2>
|
|
<p>A string is an array of bytes. Typically, they store characters encoded in
|
|
UTF-8, but you can put any byte values in there, even zero or invalid UTF-8
|
|
sequences. (You might have some trouble <em>printing</em> the latter to your terminal,
|
|
though.)</p>
|
|
<p>String literals are surrounded in double quotes:</p>
|
|
<pre class="snippet">
|
|
"hi there"
|
|
</pre>
|
|
|
|
<p>A handful of escape characters are supported:</p>
|
|
<pre class="snippet">
|
|
"\0" // The NUL byte: 0.
|
|
"\"" // A double quote character.
|
|
"\\" // A backslash.
|
|
"\%" // A percent sign.
|
|
"\a" // Alarm beep. (Who uses this?)
|
|
"\b" // Backspace.
|
|
"\f" // Formfeed.
|
|
"\n" // Newline.
|
|
"\r" // Carriage return.
|
|
"\t" // Tab.
|
|
"\v" // Vertical tab.
|
|
</pre>
|
|
|
|
<p>A <code>\u</code> followed by four hex digits can be used to specify a Unicode code point:</p>
|
|
<pre class="snippet">
|
|
System.print("\u0041\u0b83\u00DE") //> AஃÞ
|
|
</pre>
|
|
|
|
<p>A capital <code>\U</code> followed by <em>eight</em> hex digits allows Unicode code points outside
|
|
of the basic multilingual plane, like all-important emoji:</p>
|
|
<pre class="snippet">
|
|
System.print("\U0001F64A\U0001F680") //> 🙊🚀
|
|
</pre>
|
|
|
|
<p>A <code>\x</code> followed by two hex digits specifies a single unencoded byte:</p>
|
|
<pre class="snippet">
|
|
System.print("\x48\x69\x2e") //> Hi.
|
|
</pre>
|
|
|
|
<p>Strings are instances of class <a href="modules/core/string.html">String</a>.</p>
|
|
<h3>Interpolation <a href="#interpolation" name="interpolation" class="header-anchor">#</a></h3>
|
|
<p>String literals also allow <em>interpolation</em>. If you have a percent sign (<code>%</code>)
|
|
followed by a parenthesized expression, the expression is evaluated. The
|
|
resulting object’s <code>toString</code> method is called and the result is inserted in the
|
|
string:</p>
|
|
<pre class="snippet">
|
|
System.print("Math %(3 + 4 * 5) is fun!") //> Math 23 is fun!
|
|
</pre>
|
|
|
|
<p>Arbitrarily complex expressions are allowed inside the parentheses:</p>
|
|
<pre class="snippet">
|
|
System.print("wow %((1..3).map {|n| n * n}.join())") //> wow 149
|
|
</pre>
|
|
|
|
<p>An interpolated expression can even contain a string literal which in turn has
|
|
its own nested interpolations, but doing that gets unreadable pretty quickly.</p>
|
|
<h2>Ranges <a href="#ranges" name="ranges" class="header-anchor">#</a></h2>
|
|
<p>A range is a little object that represents a consecutive range of numbers. They
|
|
don’t have their own dedicated literal syntax. Instead, the number class
|
|
implements the <code>..</code> and <code>...</code> <a href="method-calls.html#operators">operators</a> to create them:</p>
|
|
<pre class="snippet">
|
|
3..8
|
|
</pre>
|
|
|
|
<p>This creates a range from three to eight, including eight itself. If you want a
|
|
half-inclusive range, use <code>...</code>:</p>
|
|
<pre class="snippet">
|
|
4...6
|
|
</pre>
|
|
|
|
<p>This creates a range from four to six <em>not</em> including six itself. Ranges are
|
|
commonly used for <a href="control-flow.html#for-statements">iterating</a> over a
|
|
sequences of numbers, but are useful in other places too. You can pass them to
|
|
a <a href="lists.html">list</a>‘s subscript operator to return a subset of the list, for
|
|
example:</p>
|
|
<pre class="snippet">
|
|
var list = ["a", "b", "c", "d", "e"]
|
|
var slice = list[1..3]
|
|
System.print(slice) //> [b, c, d]
|
|
</pre>
|
|
|
|
<p>Their class is <a href="modules/core/range.html">Range</a>.</p>
|
|
<h2>Null <a href="#null" name="null" class="header-anchor">#</a></h2>
|
|
<p>Wren has a special value <code>null</code>, which is the only instance of the class
|
|
<a href="modules/core/null.html">Null</a>. (Note the difference in case.) It functions a bit like <code>void</code> in some
|
|
languages: it indicates the absence of a value. If you call a method that
|
|
doesn’t return anything and get its returned value, you get <code>null</code> back.</p>
|
|
<p><br><hr>
|
|
<a class="right" href="lists.html">Lists →</a>
|
|
<a href="syntax.html">← Syntax</a></p>
|
|
</main>
|
|
</div>
|
|
<footer>
|
|
<div class="page">
|
|
<div class="main-column">
|
|
<p>Wren lives
|
|
<a href="https://github.com/wren-lang/wren">on GitHub</a>
|
|
— Made with ❤ by
|
|
<a href="http://journal.stuffwithstuff.com/">Bob Nystrom</a> and
|
|
<a href="https://github.com/wren-lang/wren/blob/main/AUTHORS">friends</a>.
|
|
</p>
|
|
<div class="main-column">
|
|
</div>
|
|
</footer>
|
|
</body>
|
|
</html>
|