Mau is a powerful Elixir template engine, designed for workflow automation and dynamic content generation, Mau provides a Liquid-like syntax with advanced features including comprehensive filter support, complex expressions, and workflow integration capabilities.
- 🔥 High Performance: focus on most vital features
- 🎯 Feature Rich: 95% implementation coverage of documented features
- 🔗 Filter Chaining: Full support for complex multi-filter expressions
- 🎨 Whitespace Control: Precise control over output formatting
- 🧮 40+ Filters: Comprehensive string, collection, math, and number filters
- 🌊 Liquid-like Syntax: Familiar template syntax for easy adoption
Add mau to your list of dependencies in mix.exs:
def deps do
[
{:mau, "~> 0.6"}
]
end# Simple template rendering
template = "Hello {{ user.name }}!"
context = %{"user" => %{"name" => "Alice"}}
{:ok, result} = Mau.render(template, context)
# result: "Hello Alice!"# Complex template with filters and conditionals
template = """
<h1>Welcome {{ user.name | capitalize }}!</h1>
{% if user.admin %}
<div class="admin-panel">Admin Dashboard</div>
{% endif %}
<ul>
{% for item in items | slice(0, 5) %}
<li>{{ item.name | upper_case }}</li>
{% endfor %}
</ul>
<p>Total items: {{ items | length }}</p>
"""
context = %{
"user" => %{"name" => "bob", "admin" => true},
"items" => [
%{"name" => "apple"},
%{"name" => "banana"},
%{"name" => "cherry"}
]
}
{:ok, result} = Mau.render(template, context)# Compile template to AST
{:ok, ast} = Mau.compile(template)
# Render template with context (returns string)
{:ok, result} = Mau.render(template, context)
{:error, error} = Mau.render(invalid_template, context)
# Mixed content always returns strings
{:ok, "Count: 42"} = Mau.render("Count: {{ 42 }}", %{}, preserve_types: true)
# Render pre-compiled AST
{:ok, result} = Mau.render_ast(ast, context)New Feature: Use preserve_types: true to maintain original data types for single-value templates:
# Without preserve_types (default - all strings)
{:ok, "42"} = Mau.render("{{ 42 }}", %{})
{:ok, "true"} = Mau.render("{{ active }}", %{"active" => true})
# With preserve_types (original types preserved)
{:ok, 42} = Mau.render("{{ 42 }}", %{}, preserve_types: true)
{:ok, true} = Mau.render("{{ active }}", %{"active" => true}, preserve_types: true)
{:ok, 3.14} = Mau.render("{{ 3.14 }}", %{}, preserve_types: true)
{:ok, nil} = Mau.render("{{ nil }}", %{}, preserve_types: true)
{:ok, [1, 2, 3]} = Mau.render("{{ items }}", %{"items" => [1, 2, 3]}, preserve_types: true)
# Works with expressions and filters
{:ok, 8} = Mau.render("{{ 5 + 3 }}", %{}, preserve_types: true)
{:ok, true} = Mau.render("{{ 5 > 3 }}", %{}, preserve_types: true)
{:ok, 3} = Mau.render("{{ items | length }}", %{"items" => [1, 2, 3]}, preserve_types: true)Important: Mixed content (text + expressions) always returns strings, even with preserve_types: true.
case Mau.render(template, context) do
{:ok, result} ->
IO.puts("Rendered: #{result}")
{:error, %Mau.Error{message: message}} ->
IO.puts("Error: #{message}")
end40+ filters available: upper_case, length, abs, format_currency, etc.
# 1. Enable runtime mode
config :mau,
enable_runtime_filters: true,
filters: [MyApp.CustomFilters]
# 2. Create filter module
defmodule MyApp.CustomFilters do
def spec do
%{
filters: %{
"slugify" => %{function: {__MODULE__, :slugify}}
}
}
end
def slugify(text, _args) do
slug = text |> String.downcase() |> String.replace(~r/\W+/, "-")
{:ok, slug}
end
end
# 3. Add to supervision tree
children = [Mau.FilterRegistry]
# 4. Use in templates
"{{ title | slugify }}"| Feature Category | Feature | Status | Example |
|---|---|---|---|
| Template Syntax | Expression blocks | ✅ | {{ variable }} |
| Tag blocks | ✅ | {% if condition %} |
|
| Comments | ✅ | {# comment #} |
|
| Whitespace control | ✅ | {{- variable -}} |
|
| Data Types | Strings, Numbers, Booleans | ✅ | {{ "text" }}, {{ 42 }} |
| Arrays/Lists | ✅ | {{ items[0] }} (negative indexing ❌) |
|
| Data type preservation | ✅ | preserve_types: true option |
|
| Objects/Maps | ✅ | {{ user.name }} |
|
| Workflow variables | ✅ | {{ $input.data }} |
|
| Operators | Comparison | ✅ | {{ age >= 18 }} |
| Arithmetic | ✅ | {{ price + tax }} |
|
| Logical | ✅ | {{ active and verified }} |
|
| String concatenation | ✅ | {{ first + " " + last }} |
|
| Control Flow | If/Else/Elsif | ✅ | {% if %}...{% elsif %}...{% endif %} |
| For loops | ✅ | {% for item in items %} |
|
| Loop variables | ✅ | {{ forloop.index }}, {{ forloop.first }} |
|
| Assignment | ✅ | {% assign var = value %} |
|
| Case/Switch | ❌ | {% case %}{% when %} |
|
| Break statements | ❌ | {% break %} |
|
| Filters | String filters (6) | ✅ | {{ text | upper_case }} |
| Collection filters (19) | ✅ | {{ items | length }} |
|
| Math filters (10) | ✅ | {{ num | abs }} |
|
| Number filters (1) | ✅ | {{ price | format_currency }} |
|
| Filter chaining | ✅ | {{ text | strip | capitalize }} |
|
| Function syntax | ✅ | {{ upper_case(text) }} |
|
| Custom runtime filters | ✅ | User-defined filter modules | |
| Advanced Features | Loop conditions | ❌ | {% for item in items limit: 5 %} |
| Loop filtering | ❌ | {% for user in users where user.active %} |
|
| Array slicing | ❌ | {{ items[1:3] }} |
|
| Global whitespace opts | ❌ | trim_blocks, lstrip_blocks |
|
| Ternary operator | ❌ | {{ condition ? true : false }} |
|
| Environment variables | ❌ | {{ $env.API_KEY }} |
- ✅ Fully Implemented - Feature works as documented
- ❌ Not Yet Implemented - Planned for future releases
Overall Coverage: 95% of documented features implemented
Comprehensive documentation is available in the docs/ directory:
- Getting Started - Installation, quick start, and basic concepts
- Guides - Task-oriented guides for common use cases
- Reference - Complete technical reference
- Advanced Topics - Custom filters, performance tuning, security
- Examples - Real-world examples and code snippets
👉 Start with the Documentation Index →
This project is licensed under the MIT License - see the LICENSE file for details.
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