Template Syntax

Inject Python variables directly into your HTML using double square brackets [[ ]]. The parser strictly respects boundaries, allowing for complex logic and Python-style negation inside attributes.

<span> [[ user.name ]] </span>

<!-- Python Negation & Expressions -->
<div class="[[ 'hidden' if not is_visible else 'block' ]]">
  Conditional Visibility
</div>

Use the <template> tag with casp-* directives. Unlike regex-based engines, Caspian's stack parser handles infinite nesting of loops and conditionals correctly by tracking the opening and closing of tags in a stack.

<template casp-if="not user.is_authenticated">
  <button>Login</button>
</template>

<template casp-for="category in categories">
  <h3>[[ category.name ]]</h3>
  <template casp-for="item in category.items">
    <template casp-if="item.is_active">
      <span>[[ item.name ]]</span>
    </template>
  </template>
</template>

Caspian transpiles semantic HTML tags into high-performance Jinja2 blocks. This allows you to maintain clean HTML while leveraging Python's full power. The CaspianParser converts [[ ]] to variable placeholders and <template> directives to block delimiters.

<template casp-if="user.admin">
  <p>Access Denied</p>
</template>

[% if user.admin %]
  <p>Access Denied</p>
[% endif %]

<template casp-if="not user.admin">
  <p>Access Denied</p>
</template>

[% if not user.admin %]
  <p>Access Denied</p>
[% endif %]

<template casp-for="post in posts">
  <h1>[[ post.title ]]</h1>
</template>

[% for post in posts %]
  <h1>[[ post.title ]]</h1>
[% endfor %]

Caspian automatically normalizes attributes through html_attrs.py. You can use React-style camelCase props, and they will be converted to valid HTML kebab-case automatically.