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44 lines
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2.5 KiB
HTML
<!doctype html>
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<head>
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<meta charset="utf-8">
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<meta name="viewport" content="width=device-width, initial-scale=1">
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<title>in — Ludic</title>
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<meta name="description" content="The part of a for loop that names what to iterate — a range or a query.">
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<link rel="stylesheet" href="base.css">
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<link rel="stylesheet" href="docs.css">
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</head>
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<body>
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<header class="nav"><div class="wrap nav-in"><a class="brand" href="index.html"><span class="logo">L</span> Ludic</a><button class="nav-toggle" aria-label="Toggle menu" aria-expanded="false">☰</button><nav class="nav-links"><a href="index.html">Home</a><a href="api.html">API Reference</a><a class="nav-cta" href="https://git.workshopsoft.io/workshopsoft/ludic">Source ↗</a></nav></div></header>
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<main class="wrap item">
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<div class="crumbs"><a href="api.html">API Reference</a> <span>›</span> <a href="api.html#control">Control flow</a> <span>›</span> <span class="here">in</span></div>
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<div class="item-head">
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<span class="kind-badge kind-keyword">keyword</span>
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<h1 id="top">in</h1>
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</div>
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<code class="sig">for x in range | query</code>
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<div class="desc"><p>The <code>in</code> keyword is the bridge in a <code>for</code> loop between the loop's bindings and the source it walks. On the right of <code>in</code> you write either a numeric range, <code>a .. b</code>, binding one fresh index each pass, or an ECS <code>query [...]</code>, binding one variable per non-tag property for each matching model instance. It always pairs with <code>for</code> and never stands alone. In the query form the parentheses group the bound properties — <code>for (position, velocity) in query [Position, Velocity]</code> — and the body then runs once per instance that carries them all.</p></div>
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<div class="examples"><h2>Example</h2><pre data-lang="ludic">program Movement {
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property Position { column: int = 0, row: int = 0 }
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property Velocity { delta_x: int = 0, delta_y: int = 0 }
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model Enemy { Position, Velocity }
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handler Boot phase Start {
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for slot in 0 .. 3 {
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spawn Grunt { Position { column: slot * 4, row: 2 }; Velocity { delta_x: 1 } }
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}
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}
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handler AdvancePositions phase Update {
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for (position, velocity) in query [Position, Velocity, {Enemy}] {
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position.column = position.column + velocity.delta_x
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}
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}
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}</pre></div>
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<a class="back" href="api.html">← All symbols</a>
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</main>
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<script src="ludic-highlight.js"></script>
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<script>Ludic.highlightAll(); Ludic.installCards(); Ludic.flashTarget();</script>
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</body></html> |