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Template Primitives

The blocks a .wisp template is made of, each in a few lines: conditions, loops, match, constants, snippets, components and a streamed await.

src/components/Card.wisp

{@props title, tone: &str = "plain", count: usize = 0}
<section class=${format!("card {tone}")}>
  <h3>${title}{#if count > 0} <small>(${count})</small>{/if}</h3>
  {@render children()}
</section>

<style>
  .card {
    margin: 0 0 0.75rem;
    padding: 0.75rem 1rem;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--panel);
  }

  .card.accent {
    border-color: var(--accent);
  }

  h3 {
    margin: 0 0 0.25rem;
    font-size: 1rem;
  }
</style>

src/routes/+page.wisp

---
enum Size {
    Empty,
    Few,
    Many,
}

// Ready in a moment: the page does not wait for it.
async fn weather() -> String {
    wisp::sleep(Duration::from_millis(900)).await;
    "Sunny, 21°C".to_string()
}

let size = match cx.query("size").as_deref() {
    Some("empty") => Size::Empty,
    Some("many") => Size::Many,
    _ => Size::Few,
};
let fruit: Vec<&str> = match size {
    Size::Empty => vec![],
    Size::Few => vec!["Apple", "Pear"],
    Size::Many => vec!["Apple", "Pear", "Plum", "Fig", "Kiwi"],
};
---

<title>Template Primitives</title>
<h1>Template Primitives</h1>

<nav class="sizes">
  {#each [("empty", "Empty"), ("few", "Few"), ("many", "Many")] as (key, label)}
    <a href=${format!("?size={key}")} class:on=${matches!((key, &size), ("empty", Size::Empty) | ("few", Size::Few) | ("many", Size::Many))}>${label}</a>
  {/each}
</nav>

{#snippet row(name: &str, i: usize)}
  <tr><td>${i + 1}</td><td>${name}</td><td>${name.len()} letters</td></tr>
{/snippet}

<Card title="The Fruit" tone="accent" count=${fruit.len()}>
  {#match size}
    {:case Size::Empty}<p>Nothing here.</p>
    {:case Size::Few}<p>A short list.</p>
    {:case Size::Many}<p>A long list.</p>
  {/match}
  <table>
    {#each fruit.iter().enumerate() as (i, name)}
      {@render row(name, i)}
    {:else}
      <tr><td>The bowl is empty.</td></tr>
    {/each}
  </table>
</Card>

<Card title="The Weather">
  {#await weather()}
    <p class="muted">Looking outside...</p>
  {:then w}
    <p>${w}</p>
  {/await}
</Card>

<Card title="A Constant">
  {@const total = fruit.iter().map(|f| f.len()).sum::<usize>()}
  {#if total > 12}
    <p>${total} letters in all: a mouthful.</p>
  {:else if total > 0}
    <p>${total} letters in all.</p>
  {:else}
    <p>No letters at all.</p>
  {/if}
</Card>

<style>
  .sizes {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1rem;
  }

  .sizes a {
    padding: 0.25rem 0.75rem;
    border: 1px solid var(--line);
    border-radius: 999px;
    text-decoration: none;
  }

  .sizes a.on {
    border-color: var(--accent);
    background: var(--accent);
    color: var(--on-accent);
  }

  table {
    border-collapse: collapse;
  }

  td {
    padding: 0.125rem 1rem 0.125rem 0;
  }
</style>

src/app.css

/* One small stylesheet for every example: light or dark with the system,
   violet accent, neutrals tinted toward it. */
:root {
  color-scheme: light dark;
  --bg: light-dark(oklch(0.99 0.004 295), oklch(0.2 0.014 290));
  --panel: light-dark(oklch(1 0 0), oklch(0.24 0.016 290));
  --sunk: light-dark(oklch(0.965 0.008 295), oklch(0.17 0.012 290));
  --line: light-dark(oklch(0.9 0.012 295), oklch(0.34 0.02 290));
  --ink: light-dark(oklch(0.22 0.02 290), oklch(0.96 0.006 295));
  --muted: light-dark(oklch(0.48 0.02 290), oklch(0.76 0.016 290));
  --accent: light-dark(oklch(0.5 0.21 290), oklch(0.72 0.15 292));
  --accent-strong: light-dark(oklch(0.43 0.2 290), oklch(0.8 0.12 292));
  --accent-soft: light-dark(oklch(0.95 0.03 295), oklch(0.3 0.06 290));
  --on-accent: light-dark(oklch(1 0 0), oklch(0.18 0.02 290));
  --warn: light-dark(oklch(0.52 0.17 40), oklch(0.78 0.12 50));
  --radius: 0.5rem;
  --space: 1rem;
  --mono: ui-monospace, "Cascadia Code", Menlo, monospace;
}

:root[data-theme="light"] {
  color-scheme: light;
}

:root[data-theme="dark"] {
  color-scheme: dark;
}

* {
  box-sizing: border-box;
}

body {
  max-width: 40rem;
  margin: 0 auto;
  padding: 1.5rem 1rem 3rem;
  background: var(--bg);
  color: var(--ink);
  font: 400 1rem/1.6 system-ui, -apple-system, "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
}

/* Type */

h1 {
  margin: 0 0 1rem;
  font-size: clamp(1.5rem, 1.2rem + 1.5vw, 1.875rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

h2 {
  margin: 2rem 0 0.75rem;
  font-size: 1.125rem;
  letter-spacing: -0.01em;
}

h3 {
  margin: 0 0 0.5rem;
  font-size: 1rem;
}

p {
  margin: 0 0 var(--space);
}

a {
  color: var(--accent);
  text-underline-offset: 0.2em;
}

a:hover {
  color: var(--accent-strong);
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

code {
  padding: 0.1em 0.35em;
  border-radius: 0.3em;
  background: var(--sunk);
  font: 0.875em var(--mono);
}

pre {
  margin: 0 0 var(--space);
  padding: 0.875rem 1rem;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--sunk);
  font: 0.875rem/1.55 var(--mono);
}

pre code {
  padding: 0;
  background: none;
}

.muted {
  color: var(--muted);
}

/* Nav between routes: a header of links, the current one marked. */

header,
nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.25rem;
  margin: 0 0 1.5rem;
  padding: 0 0 0.75rem;
  border-bottom: 1px solid var(--line);
  font-weight: 600;
}

header a,
nav a {
  color: var(--muted);
  text-decoration: none;
}

header a:hover,
nav a:hover,
header a[aria-current],
nav a[aria-current] {
  color: var(--ink);
}

/* Forms: fields stack their label above, the button sits at the end of the row. */

form {
  display: flex;
  flex-wrap: wrap;
  align-items: end;
  gap: 1rem 0.75rem;
  margin: 0 0 1.75rem;
}

/* A lone button with an action is a form of its own: it sits in the line. */
form:has(> button:only-child) {
  display: inline-flex;
  margin: 0;
}

label {
  position: relative;
  display: grid;
  flex: 1 1 12rem;
  gap: 0.375rem;
  color: var(--muted);
  font-size: 0.875rem;
  font-weight: 600;
}

label:has(> input[type="checkbox"]) {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  align-self: center;
}

input,
select,
textarea {
  width: 100%;
  min-height: 2.75rem;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  color: var(--ink);
  font: inherit;
  font-size: 1rem;
  font-weight: 400;
  transition: border-color 0.15s, box-shadow 0.15s;
}

input:hover,
select:hover,
textarea:hover {
  border-color: var(--muted);
}

input:focus,
select:focus,
textarea:focus {
  border-color: var(--accent);
  outline: none;
  box-shadow: 0 0 0 3px var(--accent-soft);
}

input[type="checkbox"] {
  width: 1.125rem;
  min-height: 0;
  accent-color: var(--accent);
}

input[type="file"] {
  padding: 0.4rem;
}

[aria-invalid="true"] {
  border-color: var(--warn);
}

/* A field's problem sits right under it, so the button beside the field stays put. */
label .problem {
  position: absolute;
  top: calc(100% + 0.25rem);
}

form:has(.problem) {
  row-gap: 2.25rem;
  margin-bottom: 2.75rem;
}

.problem {
  display: block;
  color: var(--warn);
  font-size: 0.8125rem;
  font-weight: 500;
}

/* Buttons */

button,
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.75rem;
  padding: 0 1.125rem;
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  background: var(--accent);
  color: var(--on-accent);
  font: 600 0.9375rem/1 system-ui, sans-serif;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, transform 0.1s;
}

button:hover,
.button:hover {
  border-color: var(--accent-strong);
  background: var(--accent-strong);
  color: var(--on-accent);
}

button:active {
  transform: translateY(1px);
}

button:disabled,
button[aria-busy="true"] {
  opacity: 0.6;
  cursor: progress;
  transform: none;
}

button.quiet {
  min-height: 2.25rem;
  padding: 0 0.75rem;
  border-color: var(--line);
  background: var(--panel);
  color: var(--ink);
  font-weight: 500;
}

button.quiet:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--ink);
}

.bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-top: 1rem;
}

/* Lists: plain ones keep their bullets; a .list is rows in a panel. */

ul,
ol {
  margin: 0 0 var(--space);
  padding-left: 1.25rem;
}

li + li {
  margin-top: 0.25rem;
}

ul.list {
  margin: 0 0 var(--space);
  padding: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  list-style: none;
}

label + ul.list {
  margin-top: 0.75rem;
}

ul.list li {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem 0.75rem;
  margin: 0;
  padding: 0.625rem 0.75rem 0.625rem 1rem;
}

ul.list li + li {
  border-top: 1px solid var(--line);
}

/* An empty list says so, quietly, in the middle. */
ul.list li.muted:only-child {
  justify-content: center;
  padding: 1.5rem 1rem;
  background: var(--sunk);
}

/* Tables */

table {
  width: 100%;
  margin: 0 0 var(--space);
  border-collapse: collapse;
  font-size: 0.9375rem;
}

th,
td {
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
}

th {
  color: var(--muted);
  font-size: 0.8125rem;
  font-weight: 600;
}

hr {
  margin: 1.5rem 0;
  border: 0;
  border-top: 1px solid var(--line);
}

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
    animation: none !important;
  }
}

src/app.html

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  %wisp.head%
</head>
<body>
  %wisp.body%
</body>
</html>

How It Works

src/routes/+page.wisp shows the template blocks in one page. The --- block picks a Size from cx.query("size") and builds the fruit list.

{#each ... as (i, name)} with {:else} draws the table rows.
{#snippet row(...)} defines a row once, and {@render row(name, i)} uses it.
{#match size} with {:case ...} picks a message.
{#await weather()} shows a placeholder while the slow async fn runs, and {:then w} shows the result. The page does not wait for it.
{@const total = ...} with {#if} and {:else if} shows one of three lines.
class:on=${...} marks the current link.

src/components/Card.wisp is the component. {@props title, tone: &str = "plain", count: usize = 0} declares its inputs, and {@render children()} draws what is inside it.

Try it in the preview: switch between Empty, Few and Many.

Take It Home

The whole app, as wisp new makes one. Unzip it, then:

cd templates
wisp dev

Download templates.zip

Learn More: Template Syntax