Variables and scope

A template gets its variables from the data you render it with, from globals, and from tags that create variables, such as set and for.

Where variables come from

When a template uses a name, Kiln looks for it in this order:

1. The parameters of the arrow function it is in.
2. Local scopes, from the innermost outwards.
3. The template scope: the render data, props, and top-level set tags.
4. Globals registered with the environment.

Functions, filters and tests have their own names, separate from variables. A variable called range never hides the range() function.

Scopes

These tags create a new scope: each for iteration, with, block, macro, include, component and fill. Variables made inside a scope disappear when it ends.

if, apply and autoescape don't create a scope.

Assigning variables

set updates a variable where it already exists. If the variable doesn't exist yet, set creates it in the current scope.

{% set total = 0 %}
{% for item in items %}
	{% set total = total + item.price %}
{% endfor %}
Total: {{ total }}

Total: 7

Because total existed before the loop, the loop updates it. A variable first set inside the loop only exists inside the loop.

You can't assign to loop, slots or a global.

Isolated templates

Included templates, components and macros don't see the caller's variables. They only see what you pass them, plus globals. This keeps each template's inputs clear.

{% include "partials/header" with { page, nav } %}