# `HuggingfaceClient.Jinja`
[🔗](https://github.com/huggingface/huggingface_client/blob/v0.1.0/lib/huggingface_client/jinja.ex#L1)

A Jinja2-compatible template engine for rendering HuggingFace chat templates.

Supports a broad subset of Jinja2 including:

- Variable interpolation `{{ expr }}`
- Control tags `{% if %}`, `{% for %}`, `{% set %}`, `{% macro %}`
- Filters: `upper`, `lower`, `trim`, `reverse`, `length`, `first`, `last`,
  `join`, `replace`, `default`, `truncate`, `title`, `sort`, `unique`
- `loop` object: `.index`, `.index0`, `.first`, `.last`, `.length`
- Arithmetic: `+`, `-`, `*`, `//`, `**`; concatenation: `~`
- Index/slice access: `x[0]`, `x[-1]`, `x[1:3]`, `x["key"]`
- `is` tests: `defined`, `string`, `integer`, `none`
- `in` / `not in` operators
- Ternary: `"yes" if cond else "no"`
- Comments `{# ... #}`
- `range(n)` / `range(start, stop)`

## Usage

    {:ok, "Hello, World!"} = HuggingfaceClient.Jinja.render("Hello, {{ name }}!", %{"name" => "World"})

    {:ok, text} = HuggingfaceClient.Jinja.apply_chat_template(template, messages, %{"add_generation_prompt" => true})

# `apply_chat_template`

```elixir
@spec apply_chat_template(String.t(), list(), map()) ::
  {:ok, String.t()} | {:error, term()}
```

Applies a chat template (Jinja2) to a list of messages.

`extra_vars` is merged into the template context alongside `messages`.

# `render`

```elixir
@spec render(String.t(), map()) :: {:ok, String.t()} | {:error, term()}
```

Renders a Jinja2 template string with the given variable map.

Returns `{:ok, rendered_string}` or `{:error, reason}`.

---

*Consult [api-reference.md](api-reference.md) for complete listing*