https://docs.rs/mystical-runic

🔮 Mystical-Runic - High-Performance Template Engine

Zero-dependency, high-performance templating engine for Rust with enterprise-grade features

Mystical-Runic is a high-performance templating engine that combines the simplicity of Mustache syntax with powerful enterprise features. Built for production use with zero external dependencies, comprehensive security, and exceptional performance.

📚 Documentation

Type	Description	Lien
🦀 API Reference	Complete technical documentation	docs.rs/mystical-runic
🇫🇷 Guide Utilisateur	Documentation française avec tutoriels	Documentation HTML
📖 Quick Start	cargo doc --open --all-features	Documentation locale
🎯 Examples	Real-world demos and usage examples	examples/

💡 Tip: Start with the French user guide for tutorials and examples, then use the API reference for technical details.

✨ Features

🎯 Core Template Engine

• 🎭 Dual API Style: Choose between conventional (TemplateEngine) or mystical (RuneEngine) naming
• 🎯 Simple API: Clean, intuitive interface for Rust developers
• 🌊 Deep Object Navigation: Unlimited depth dot notation (e.g., {{user.profile.stats.level}})
• 🔄 Nested Templates: Full support for nested loops and recursive template includes
• 🏗️ Template Inheritance: Advanced layout system with nested inheritance and {{super}}
• 📦 Reusable Macros: Define and reuse template components with parameters

🔧 Filters & Transformations

• 🔧 Powerful Filters: Built-in filters like upper, lower, currency, truncate with chaining support
• 🔢 Advanced Math Filters: Mathematical operations with add, multiply, divide, percentage, round
• 🎨 Custom Filter API: Register your own filters for domain-specific transformations
• 🌐 Internationalization (i18n): Multi-language support with {{t "key"}} syntax and locale switching
• 📝 Smart Pluralization: Automatic plural forms with {{plural count "item" "items"}}

🔒 Security & Quality

• 🔒 Security First: XSS-safe by default with comprehensive HTML escaping
• 🛡️ Path Traversal Protection: Enterprise-grade security preventing ../ attacks
• 🔒 Enterprise Security: Threat classification and audit logging (v0.5.1)
• 🧪 Well Tested: 204+ tests with comprehensive coverage following strict TDD methodology
• 📦 Zero Dependencies: Pure Rust implementation with no external dependencies

⚡ Performance & Monitoring

• ⚡ High Performance: Template caching, bytecode compilation, parallel processing
• 📈 Performance Monitoring: Advanced metrics collection and optimization (v0.5.1)
• 🦀 Modern Rust: Rust 2021 edition with 1.74.0+ MSRV, future Rust 2024 ready

🛠️ Developer Experience

• 🔍 Enhanced Error Messages: Line/column numbers with helpful suggestions and context (v0.4.0)
• 🐛 Template Debugging: Step-through debugging with variable tracking and execution insights (v0.4.0)
• 🔥 Hot Reload: Development-time template reloading for faster iteration cycles (v0.4.0)
• 💻 IDE Integration: Full Language Server Protocol support with auto-completion, syntax highlighting, error squiggles (v0.4.1)

🌐 Ecosystem Integration (v0.5.0+)

• 🚀 Async Support: Non-blocking template rendering for high-performance web applications
• 🌐 Web Framework Integration: First-class support for Axum, Warp, and Actix-web
• 🕸️ WASM Ready: Browser-compatible template rendering with JavaScript bindings
• 🛠️ CLI Tools: Command-line template processing with watching and batch operations

📝 Template Syntax

Core Features

• Variables: {{name}} - HTML-escaped variable output for XSS protection
• Raw HTML: {{& html}} - Unescaped HTML output (use with caution)
• Conditionals: {{if condition}}...{{/if}} - Conditional rendering with comparison operators
• Loops: {{for item in items}}...{{/for}} - Iterate over arrays and objects
• Includes: {{include "template.html"}} - Template composition and reuse
• Comments: {{! comment }} - Template comments (not rendered)
• Deep Access: {{user.profile.stats.level}} - Unlimited depth object property access

Advanced Sorcery (v0.2.0)

• Sacred Inheritance: {{extends "base.html"}} - Inherit the power of ancestral templates
• Mystical Blocks: {{block content}}...{{/block}} - Define regions of power in your layouts
• Ancestral Wisdom: {{super}} - Channel the content of parent templates
• Transformation Filters: {{name|upper|truncate:10}} - Transform values with ancient filters
• Reusable Spells (Macros): {{macro spell(power)}}...{{/macro}} - Create reusable incantations
• Spell Invocation: {{spell("lightning")}} - Call upon your defined macros

Master Sorcery (v0.3.4) - The Advanced Features

• Nested Loop Mastery: {{for category in shops}}{{for item in category.items}}...{{/for}}{{/for}} - Complex nested iterations with stack-based parsing
• Recursive Includes: Templates can include other templates that include more templates - unlimited depth!
• Path Traversal Wards: Enterprise-grade protection against ../../../etc/passwd and C:\Windows\System32 attacks
• Multilingual Magic: {{t "welcome" name=user}} - Full i18n with variable interpolation
• Smart Plurals: {{plural count "item" "items"}} - Automatic singular/plural forms
• Mathematical Alchemy: {{price|multiply:1.2|add:shipping|round:2|currency}} - Complex calculations with filter chaining
• Custom Enchantments: Register your own filters with engine.register_filter()

Global Sorcery (v0.3.0)

• Universal Translation: {{t "welcome"}} - Speak all tongues with i18n support
• Locale Switching: Switch between languages with engine.set_locale("en")
• Quantity Wisdom: {{plural count "item" "items"}} - Smart pluralization magic
• Mathematical Alchemy: {{price|add:10|multiply:2|percentage}} - Advanced math transformations
• Custom Enchantments: engine.register_filter("reverse", |input, _| Ok(input.chars().rev().collect())) - Forge your own filters

Developer Experience (v0.4.0) - The Debugging Edition

• Enhanced Error Diagnostics: ParseWithLocation - Precise line/column error reporting with context
• Intelligent Suggestions: Template and variable name suggestions for typos
• Debug Mode: engine.enable_debug_mode() - Variable tracking and execution step analysis
• Template Debugging: render_string_with_debug() - Step-through debugging with performance metrics
• Hot Reload: engine.enable_hot_reload() - Automatic template reloading during development
• Developer-Friendly Errors: Stack traces for nested template errors with full context

IDE Integration (v0.4.1) - The Editor Edition

• Language Server Protocol: parse_for_lsp() - Full LSP support for template editing
• Auto-completion: Smart suggestions for variables, filters, and template syntax
• Syntax Highlighting: Rich syntax highlighting with error detection
• Hover Information: Contextual help and variable type information
• Go-to-Definition: Navigate to template includes and macro definitions
• Real-time Diagnostics: Live error checking with squiggly underlines

Ecosystem Integration (v0.5.0) - The Modern Web Edition

• Async Support: render_string_async() - Non-blocking template rendering with tokio
• Concurrent Rendering: Clone engines for parallel template processing
• Web Framework Integration:
  • Axum: engine.render_axum() - Direct HTML responses
  • Warp: engine.render_warp() - Reply trait integration
  • Actix: engine.render_actix() - HttpResponse integration
• WASM Compatibility: WasmRuneEngine - Browser-ready template rendering
• JavaScript Bindings: engine.render_string(template, json) for web apps
• CLI Tools: Command-line template processing utilities
  • process_template() - Direct string processing
  • process_files() - File-based template rendering
  • batch_process() - Multiple template processing
  • TemplateWatcher - File system watching with hot reload
• Configuration Management: TOML-based configuration loading
• Go to Definition: get_definition_at_position() - Navigate to macro definitions

🚀 Quick Start

📖 Complete setup guide: See our detailed installation documentation for comprehensive instructions and examples.

Installation

Basic Installation

[dependencies]
mystical-runic = "0.5.2"

With Ecosystem Integration Features (v0.5.0)

[dependencies]
# Async support for high-performance web apps
mystical-runic = { version = "0.5.2", features = ["async"] }

# Web framework integration
mystical-runic = { version = "0.5.2", features = ["web-frameworks"] }
# Or specific frameworks:
# mystical-runic = { version = "0.5.2", features = ["axum-integration"] }
# mystical-runic = { version = "0.5.2", features = ["warp-integration"] }
# mystical-runic = { version = "0.5.2", features = ["actix-integration"] }

# WASM browser compatibility
mystical-runic = { version = "0.5.2", features = ["wasm"] }

# CLI tools and utilities
mystical-runic = { version = "0.5.2", features = ["cli"] }

# All ecosystem features
mystical-runic = { version = "0.5.2", features = ["full"] }

Available Features:

Feature	Description	Category
async	Async template rendering with Tokio	🚀 Performance
axum-integration	Axum web framework support	🌐 Web Frameworks
warp-integration	Warp web framework support	🌐 Web Frameworks
actix-integration	Actix-web framework support	🌐 Web Frameworks
web-frameworks	All web framework integrations	🌐 Web Frameworks
wasm	WebAssembly browser compatibility	🕸️ Browser/WASM
cli	Command-line tools and utilities	🛠️ Developer Tools
full	All ecosystem integration features	📦 Complete Package

Basic Usage - Choose Your Style! 🎭

🏢 Conventional Style

Perfect for corporate environments, team projects, and those who prefer explicit naming:

use mystical_runic::{TemplateEngine, TemplateContext, TemplateValue};

let mut engine = TemplateEngine::new("templates");
let mut context = TemplateContext::new();

// Set variables in your template context
context.set("hero", TemplateValue::String("Rust Developer".to_string()));
context.set("level", TemplateValue::Number(99));
context.set("has_coffee", TemplateValue::Bool(true));

let result = engine.render_string(
    "Hello {{hero}} of level {{level}}! {{if has_coffee}}☕ Ready to work!{{/if}}", 
    &context
).unwrap();

🔮 Mystical Style (Themed)

For the adventurous, creative projects, and those who enjoy a touch of magic:

use mystical_runic::{RuneEngine, RuneScroll, RuneSymbol};

// Summon the ancient engine from the template realm
let mut engine = RuneEngine::new("sacred_scrolls");
let mut scroll = RuneScroll::new();

// Inscribe your desires upon the scroll
scroll.set("hero", RuneSymbol::String("Mystical Sorcerer".to_string()));
scroll.set("level", RuneSymbol::Number(99));
scroll.set("has_coffee", RuneSymbol::Bool(true));

// Speak the incantation and witness the transformation
let result = engine.render_string(
    "Behold! {{hero}} of level {{level}} embarks upon their quest! {{if has_coffee}}☕{{/if}}", 
    &scroll
).unwrap();

💡 Pro Tip: Both styles are completely interchangeable! Use whichever feels right for your project. You can even mix them in the same codebase - they're just aliases for the same underlying types.

Advanced Example: Character Sheet Generator

use mystical_runic::{RuneEngine, RuneScroll, RuneSymbol};
use std::collections::HashMap;

let mut engine = RuneEngine::new(".");
let mut scroll = RuneScroll::new();

// Create a magical character
let mut character = HashMap::new();
character.insert("name".to_string(), RuneSymbol::String("Gandalf the Grey".to_string()));
character.insert("class".to_string(), RuneSymbol::String("Wizard".to_string()));
character.insert("level".to_string(), RuneSymbol::Number(85));
character.insert("mana".to_string(), RuneSymbol::Number(9999));
character.insert("has_staff".to_string(), RuneSymbol::Bool(true));

scroll.set("character", RuneSymbol::Object(character));

// ⚔️ Create spell list
let spells = vec![
    create_spell("Fireball", 50, "🔥"),
    create_spell("Lightning Bolt", 75, "⚡"),
    create_spell("Ice Shard", 40, "❄️"),
];
scroll.set("spells", RuneSymbol::Array(spells));

let character_sheet = r#"
🧙‍♂️ Name: {{character.name}}
🎓 Class: {{character.class}} (Level {{character.level}})
🔮 Mana: {{character.mana}}

{{if character.has_staff}}
🪄 Equipment: Magical Staff of Power
{{/if}}

⚡ KNOWN SPELLS:
{{for spell in spells}}
  {{spell.icon}} {{spell.name}} - Power: {{spell.damage}}
{{/for}}
"#;

let result = engine.render_string(character_sheet, &scroll).unwrap();
println!("{}", result);

fn create_spell(name: &str, damage: i64, icon: &str) -> RuneSymbol {
    let mut spell = HashMap::new();
    spell.insert("name".to_string(), RuneSymbol::String(name.to_string()));
    spell.insert("damage".to_string(), RuneSymbol::Number(damage));
    spell.insert("icon".to_string(), RuneSymbol::String(icon.to_string()));
    RuneSymbol::Object(spell)
}

Deep Dot Notation Example

use mystical_runic::{RuneEngine, RuneScroll, RuneSymbol};
use std::collections::HashMap;

let mut engine = RuneEngine::new(".");
let mut scroll = RuneScroll::new();

// Create deeply nested game data structure
let mut stats = HashMap::new();
stats.insert("level".to_string(), RuneSymbol::Number(42));
stats.insert("health".to_string(), RuneSymbol::Number(100));
stats.insert("mana".to_string(), RuneSymbol::Number(75));

let mut equipment = HashMap::new();
equipment.insert("weapon".to_string(), RuneSymbol::String("Mystical Sword".to_string()));
equipment.insert("armor".to_string(), RuneSymbol::String("Dragon Scale".to_string()));

let mut character = HashMap::new();
character.insert("name".to_string(), RuneSymbol::String("Aragorn".to_string()));
character.insert("class".to_string(), RuneSymbol::String("Ranger".to_string()));
character.insert("stats".to_string(), RuneSymbol::Object(stats));
character.insert("equipment".to_string(), RuneSymbol::Object(equipment));

let mut game_data = HashMap::new();
game_data.insert("character".to_string(), RuneSymbol::Object(character));

scroll.set("game", RuneSymbol::Object(game_data));

// Use deep dot notation to access nested values
let template = r#"
🎮 GAME CHARACTER SHEET 🎮

👤 Name: {{game.character.name}}
🎭 Class: {{game.character.class}}

📊 STATS:
❤️ Health: {{game.character.stats.health}}
💙 Mana: {{game.character.stats.mana}}
⭐ Level: {{game.character.stats.level}}

⚔️ EQUIPMENT:
{{if game.character.equipment.weapon}}
🗡️ Weapon: {{game.character.equipment.weapon}}
{{/if}}
{{if game.character.equipment.armor}}
🛡️ Armor: {{game.character.equipment.armor}}
{{/if}}

{{if game.character.stats.level}}
🏆 Status: {{if game.character.stats.health}}Combat Ready{{/if}}
{{/if}}
"#;

let result = engine.render_string(template, &scroll).unwrap();
println!("{}", result);

// 🔥 NEW v0.4.0: Debug Mode for Development
engine.enable_debug_mode();
let debug_result = engine.render_string_with_debug(template, &scroll).unwrap();

println!("Rendered: {}", debug_result.output);
println!("Variables accessed: {:?}", debug_result.debug_info.variables_accessed);
println!("Execution time: {}ms", debug_result.debug_info.performance_metrics.total_time_nanos / 1_000_000);

IDE Integration Example (v0.4.1)

use mystical_runic::{RuneEngine, RuneScroll, RuneSymbol};

let mut engine = RuneEngine::new(".");
let mut context = RuneScroll::new();
context.set_string("user_name", "Alice");
context.set_number("user_level", 42);

let template = r#"
{{macro greeting(name, level)}}
<h1>Hello {{name}}! Level: {{level}}</h1>
{{/macro}}

{{greeting(user_name, user_level)}}
{{if user_level}}
    {{user_name|upper}} is ready!
{{/if}}
"#;

// 🔍 NEW v0.4.1: Language Server Protocol Support
let lsp_info = engine.parse_for_lsp(template, "greeting.html").unwrap();
println!("Variables found: {:?}", lsp_info.variables);
println!("Macros found: {:?}", lsp_info.macros);

// 💡 NEW v0.4.1: Auto-completion at cursor position  
let position = 95; // Position in "{{user_na|" 
let completions = engine.get_completions_at_position(template, position, &context).unwrap();
for completion in completions {
    println!("Suggestion: {} ({})", completion.label, completion.completion_type);
}

// 🎨 NEW v0.4.1: Syntax highlighting tokens
let tokens = engine.tokenize_for_syntax_highlighting(template).unwrap();
for token in tokens.iter().take(5) {
    println!("Token: '{}' ({})", token.content, token.token_type);
}

// 🚨 NEW v0.4.1: Real-time error diagnostics
let invalid_template = "{{name}} {{unknown_variable}} {{name|nonexistent_filter}}";
let diagnostics = engine.get_diagnostics_for_editor(invalid_template, &context).unwrap();
for diagnostic in diagnostics {
    println!("⚠️ {}: {} (line {})", diagnostic.severity, diagnostic.message, diagnostic.line);
}

// ℹ️ NEW v0.4.1: Hover information  
let hover_position = 50; // Position over a variable
if let Ok(hover_info) = engine.get_hover_info_at_position(template, hover_position, &context) {
    println!("Hover: {} ({}) = {}", hover_info.variable_name, hover_info.variable_type, hover_info.current_value);
}

// 🔍 NEW v0.4.1: Go to definition
let macro_position = 200; // Position over a macro call
if let Ok(definition) = engine.get_definition_at_position(template, macro_position) {
    println!("Definition: {} at line {} column {}", definition.name, definition.line, definition.column);
}

Ecosystem Integration Examples (v0.5.0)

Async Template Rendering

use mystical_runic::{RuneEngine, RuneScroll, AsyncTemplateEngine};
use tokio;

#[tokio::main]
async fn main() {
    let mut engine = RuneEngine::new("templates");
    let mut context = RuneScroll::new();
    context.set_string("user", "Async Wizard");
    
    // Non-blocking template rendering
    let result = engine.render_string_async(
        "Hello {{user}}! Processing your request...", 
        &context
    ).await.unwrap();
    
    println!("{}", result);
}

Web Framework Integration

Axum Integration

use axum::{response::Html, routing::get, Router};
use mystical_runic::{RuneEngine, RuneScroll, AxumTemplateEngine};

async fn render_page(mut engine: RuneEngine) -> Result<Html<String>, String> {
    let mut context = RuneScroll::new();
    context.set_string("title", "My Axum App");
    
    engine.render_axum("<h1>{{title}}</h1>", &context)
        .await
        .map_err(|e| e.to_string())
}

#[tokio::main]
async fn main() {
    let app = Router::new()
        .route("/", get(|| render_page(RuneEngine::new("templates"))));
        
    // Serve your app...
}

WASM Browser Integration

use mystical_runic::WasmRuneEngine;
use wasm_bindgen::prelude::*;

#[wasm_bindgen]
pub fn render_in_browser() -> Result<String, JsValue> {
    let mut engine = WasmRuneEngine::new();
    engine.enable_console_logging(true);
    
    let template = r#"
        <div class="user-card">
            <h2>{{user.name}}</h2>
            <p>Level: {{user.level}}</p>
        </div>
    "#;
    
    let context_json = r#"{"user": {"name": "Web Wizard", "level": 42}}"#;
    
    engine.render_string(template, context_json)
}

CLI Tools Integration

use mystical_runic::{process_template, process_files, batch_process};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Direct template processing
    let template = "Hello {{name}}!";
    let data = r#"{"name": "CLI User"}"#;
    let result = process_template(template, data)?;
    println!("{}", result);
    
    // File-based processing
    let output = process_files("template.html", "data.json")?;
    println!("File result: {}", output);
    
    // Batch processing
    let templates = vec!["template1.html", "template2.html"];
    let context_json = r#"{"theme": "dark", "version": "v0.5.0"}"#;
    let results = batch_process(templates, context_json)?;
    
    for (i, result) in results.iter().enumerate() {
        println!("Template {}: {}", i + 1, result);
    }
    
    Ok(())
}

🎮 Complete Real-World Demo Application

Experience ALL features of Mystical-Runic v0.5.0 with our comprehensive demonstration application!

# Run the complete feature showcase
cd examples/real_world_demo
./run_demo.sh

# OR manually
cargo run

🌟 What the Demo Showcases

Our demo application is a full-featured e-commerce/blog site that demonstrates every single feature:

• 🔄 NEW v0.3.4: Nested loops with complex data structures (categories → products)
• 🔄 NEW v0.3.4: Recursive includes with 4 levels deep (profile → stats → preferences → comments)
• 🛡️ NEW v0.3.4: Path traversal protection blocking ../../../etc/passwd attacks
• 🏗️ Template inheritance with base.html → shop.html
• 🌐 Full i18n with French/English translations
• 📝 Smart pluralization throughout the interface
• 🔢 Advanced math filters for pricing, taxes, discounts
• 🎨 Custom filters for encryption, markdown, dates
• 📦 Reusable macros for product cards
• 🌊 Deep dot notation accessing user.profile.settings.theme
• 🔒 XSS protection with real attack demonstrations
• ⚡ Performance features with benchmarking

📊 Demo Results

🔮 MYSTICAL-RUNIC v0.3.4 - DÉMONSTRATION COMPLÈTE!
✅ Main template rendered successfully! (10KB+ HTML)
✅ Nested loops work perfectly!
✅ Nested includes work perfectly! 
✅ All path traversal attempts blocked!
✅ XSS protection working
✅ Rendered 100 times in 1-2ms
✅ HTML file generated: output_demo.html

🎉 All 173+ tests pass! Production ready!

🎯 Generated Output

The demo creates output_demo.html - a complete working website showcasing:

• Clean styling with responsive design
• Real e-commerce functionality simulation
• Complex nested data visualization
• Multi-language interface
• Security feature demonstrations
• Performance metrics display

📁 Location: examples/real_world_demo/ - Complete application with 7+ templates, realistic data, and full documentation.

🏰 Template Inheritance (v0.2.0)

Create sophisticated layouts with template inheritance:

<!-- base.html -->
<!DOCTYPE html>
<html>
<head>
    <title>{{block title}}My Site{{/block}}</title>
</head>
<body>
    <header>{{block header}}Default Header{{/block}}</header>
    <main>{{block content}}{{/block}}</main>
    <footer>{{block footer}}© 2024 My Site{{/block}}</footer>
</body>
</html>

<!-- admin.html -->
{{extends "base.html"}}

{{block title}}Admin Panel - {{block page_title}}{{/block}}{{/block}}

{{block content}}
<div class="admin-layout">
    <nav>{{block sidebar}}Default Sidebar{{/block}}</nav>
    <main>{{block admin_content}}{{/block}}</main>
</div>
{{/block}}

<!-- admin_users.html -->
{{extends "admin.html"}}

{{block page_title}}User Management{{/block}}

{{block admin_content}}
<h1>Users</h1>
{{for user in users}}
    <div class="user-card">{{user.name}} - {{user.role}}</div>
{{/for}}
{{/block}}

🔧 Powerful Filters (v0.2.0)

Transform your data with built-in filters:

<h1>{{title|upper}}</h1>                    <!-- HELLO WORLD -->
<p>{{description|lower}}</p>                <!-- hello world -->
<span>${{price|currency}}</span>            <!-- $12.99 -->
<div>{{content|truncate:50}}</div>          <!-- Truncated text... -->
<time>{{date|date:"Y-m-d"}}</time>          <!-- 2024-01-15 -->

<!-- Chain multiple filters -->
<p>{{name|lower|capitalize}}</p>            <!-- John Doe -->
<span>{{text|strip|truncate:20|upper}}</span>   <!-- TRIMMED TEXT... -->

📦 Reusable Macros (v0.2.0)

Create reusable template components:

<!-- Define macros -->
{{macro button(text, type="button", class="btn")}}
<button type="{{type}}" class="{{class}}">{{text}}</button>
{{/macro}}

{{macro card(title, content, class="card")}}
<div class="{{class}}">
    <h3 class="card-title">{{title}}</h3>
    <div class="card-body">{{content}}</div>
</div>
{{/macro}}

{{macro user_card(user)}}
<div class="user-card">
    <h4>{{user.name}}</h4>
    <p>{{user.email}}</p>
    {{if user.active}}
        <span class="status active">Online</span>
    {{/if}}
</div>
{{/macro}}

<!-- Use macros -->
{{button("Save", type="submit", class="btn btn-primary")}}
{{card("Welcome", "This is a welcome message", class="card highlight")}}

{{for user in users}}
    {{user_card(user)}}
{{/for}}

📖 Template Syntax Guide

Variables

<!-- Safe HTML escaping (default) -->
<p>{{user_input}}</p>

<!-- Raw HTML output (use with caution) -->
<div>{{& trusted_html}}</div>

<!-- Object properties -->
<span>{{user.name}} ({{user.email}})</span>

<!-- Deep nested properties -->
<div>Level: {{player.character.stats.level}}</div>
<p>{{config.database.connection.host}}:{{config.database.connection.port}}</p>

Conditionals

{{if user.is_admin}}
  <button class="admin-panel">Admin Controls</button>
{{/if}}

{{if items}}
  <ul class="item-list">
    <!-- items exist -->
  </ul>
{{/if}}

<!-- Deep conditionals -->
{{if user.settings.notifications.email.enabled}}
  <p>Email notifications are on</p>
{{/if}}

{{if config.features.advanced.enabled}}
  <div class="advanced-features">Advanced mode active</div>
{{/if}}

Truthiness Rules:

• Strings: non-empty = true, empty = false
• Numbers: non-zero = true, zero = false
• Booleans: as expected
• Arrays: non-empty = true, empty = false
• Objects: non-empty = true, empty = false

Loops

{{for product in products}}
  <div class="product">
    <h3>{{product.name}}</h3>
    <p>Price: ${{product.price}}</p>
    {{if product.on_sale}}
      <span class="sale-badge">ON SALE!</span>
    {{/if}}
  </div>
{{/for}}

Template Includes

<!-- main.html -->
<!DOCTYPE html>
<html>
<head>
  {{include "partials/head.html"}}
</head>
<body>
  {{include "partials/header.html"}}
  <main>{{content}}</main>
  {{include "partials/footer.html"}}
</body>
</html>

Comments

{{! This comment will not appear in the output }}
<div>
  {{! 
    Multi-line comments
    are also supported
  }}
  <p>Visible content</p>
</div>

🔒 Security Features

Mystical-Runic takes security seriously and provides multiple layers of protection:

XSS Prevention

let mut context = RuneScroll::new();
context.set_string("user_input", "<script>alert('xss')</script>");

let result = engine.render_string("{{user_input}}", &context).unwrap();
// Output: &lt;script&gt;alert(&#x27;xss&#x27;)&lt;/script&gt;

Path Traversal Protection

// These will safely fail:
engine.render("../../../etc/passwd", &context);  // ❌ Blocked
engine.render("..\\windows\\system32", &context);  // ❌ Blocked

Template Injection Prevention

context.set_string("malicious", "{{admin_password}}");
let result = engine.render_string("{{malicious}}", &context).unwrap();
// Output: {{admin_password}} (literal text, not executed)

🎨 API Reference

RuneEngine (TemplateEngine)

let mut engine = RuneEngine::new("path/to/templates");

// Render from file
let result = engine.render("template.html", &context)?;

// Render from string
let result = engine.render_string("Hello {{name}}!", &context)?;

// Load template (with caching)
let template_content = engine.load_template("header.html")?;

RuneScroll (TemplateContext)

let mut scroll = RuneScroll::new();

// Set different value types
scroll.set_string("name", "value");
scroll.set_number("count", 42);
scroll.set_bool("active", true);

// Set complex values
scroll.set("array", RuneSymbol::Array(vec![...]));
scroll.set("object", RuneSymbol::Object(hashmap));

// Retrieve values
let value = scroll.get_string("name");

RuneSymbol (TemplateValue)

// Create different value types
let string_val = RuneSymbol::String("text".to_string());
let number_val = RuneSymbol::Number(42);
let bool_val = RuneSymbol::Bool(true);
let array_val = RuneSymbol::Array(vec![...]);
let object_val = RuneSymbol::Object(hashmap);

🧪 Testing

Run the comprehensive test suite:

# Run all tests
cargo test

# Run specific test categories
cargo test integration_tests
cargo test unit_tests
cargo test security_tests

# Run with output
cargo test -- --nocapture

Internationalization Example (v0.3.0)

use mystical_runic::{RuneEngine, RuneScroll, RuneSymbol};
use std::collections::HashMap;

let mut engine = RuneEngine::new("./templates");
let mut context = RuneScroll::new();
context.set("name", RuneSymbol::String("Alice".to_string()));

// Set up English translations
let mut en_translations = HashMap::new();
en_translations.insert("welcome".to_string(), "Welcome {{name}}!".to_string());
engine.set_translations("en", en_translations);

// Set up French translations
let mut fr_translations = HashMap::new();
fr_translations.insert("welcome".to_string(), "Bienvenue {{name}}!".to_string());
engine.set_translations("fr", fr_translations);

// Use English
engine.set_locale("en");
let welcome_en = engine.render_string("{{t \"welcome\"}}", &context).unwrap();
// Output: "Welcome Alice!"

// Switch to French
engine.set_locale("fr");
let welcome_fr = engine.render_string("{{t \"welcome\"}}", &context).unwrap();
// Output: "Bienvenue Alice!"

Custom Filters Example (v0.3.0)

use mystical_runic::{RuneEngine, RuneScroll, RuneSymbol};

let mut engine = RuneEngine::new("./templates");
let mut context = RuneScroll::new();
context.set("text", RuneSymbol::String("hello world".to_string()));

// Register custom filters
engine.register_filter("reverse", |input: &str, _args: &[&str]| {
    Ok(input.chars().rev().collect())
});

engine.register_filter("repeat", |input: &str, args: &[&str]| {
    let times = args.get(0).map_or("1", |v| v).parse::<usize>().unwrap_or(1);
    Ok(input.repeat(times))
});

let result = engine.render_string("{{text|reverse|upper|repeat:2}}", &context).unwrap();
// Output: "DLROW OLLEHDLROW OLLEH"

Math Filters Example (v0.3.0)

use mystical_runic::{RuneEngine, RuneScroll, RuneSymbol};

let mut engine = RuneEngine::new("./templates");
let mut context = RuneScroll::new();
context.set("price", RuneSymbol::Number(100));
context.set("tax_rate", RuneSymbol::Number(8));

// Complex calculations with chaining
let template = "Price: ${{price}}, Total: {{price|multiply:tax_rate|divide:100|add:price|round:2}}";
let result = engine.render_string(template, &context).unwrap();
// Output: "Price: $100, Total: 108.00"

Pluralization Example (v0.3.0)

use mystical_runic::{RuneEngine, RuneScroll, RuneSymbol};

let mut engine = RuneEngine::new("./templates");
let mut context = RuneScroll::new();

let template = "You have {{count}} {{plural count \"apple\" \"apples\"}}";

context.set("count", RuneSymbol::Number(1));
let result = engine.render_string(template, &context).unwrap();
// Output: "You have 1 apple"

context.set("count", RuneSymbol::Number(5)); 
let result = engine.render_string(template, &context).unwrap();
// Output: "You have 5 apples"

🔮 Examples

Check out the examples/ directory for magical demonstrations:

• real_world_demo/ - ⭐ COMPLETE DEMO APPLICATION - Full-featured e-commerce/blog showcasing ALL v0.3.4 features
  • 🎮 Run with: cd examples/real_world_demo && ./run_demo.sh
  • 📄 Generates complete HTML website (10KB+)
  • 🔄 NEW: Nested loops, recursive includes, path traversal protection
  • 🌐 Multi-language (FR/EN), math filters, custom filters, macros, inheritance
• spell_casting.rs - Fantasy RPG character sheet generator
• More examples coming with each release!

🦀 Rust Compatibility

Minimum Supported Rust Version (MSRV): 1.74.0+
Edition: Rust 2021 (with future Rust 2024 readiness)
Tested on: Rust 1.74.0 through latest stable

Future-Proof Design

• Modern Rust patterns and idioms
• Prepared for Rust 2024 edition migration
• Zero unsafe code
• Comprehensive test coverage (173+ tests)
• Zero compilation warnings

Development Setup

git clone https://github.com/yrbane/mystical-runic.git
cd mystical-runic
cargo build
cargo test

🧪 Test-Driven Development (TDD) Methodology

Mystical-Runic follows strict Test-Driven Development practices. When contributing, please observe the sacred TDD ritual:

🔴 Red → 🟢 Green → 🔵 Refactor Cycle

1. 🔴 RED - Write a Failing Test First

   # Write your test before any implementation
   cargo test your_new_feature_test
   # ❌ Should fail - good!
   

2. 🟢 GREEN - Write Minimal Code to Pass

   # Write just enough code to make the test pass
   cargo test your_new_feature_test
   # ✅ Should pass - excellent!
   

3. 🔵 REFACTOR - Improve Without Breaking

   # Clean up code while keeping tests green
   cargo test  # All tests should still pass
   

---

"Tests are the safety net that lets you refactor fearlessly." — TDD Proverb

📜 Changelog

v0.4.1 (Latest Release) - The IDE Integration Edition

• 💻 NEW: Language Server Protocol Support: Complete LSP implementation for template editing with parse_for_lsp()
• 🎨 NEW: Syntax Highlighting: Semantic token analysis with tokenize_for_syntax_highlighting() for editor integration
• 💡 NEW: Auto-completion: Intelligent completion for variables, filters, and directives with get_completions_at_position()
• 🚨 NEW: Real-time Diagnostics: Error squiggles and warnings with get_diagnostics_for_editor() for live error detection
• ℹ️ NEW: Hover Information: Variable type and value inspection with get_hover_info_at_position()
• 🔍 NEW: Go to Definition: Navigate to macro definitions with get_definition_at_position()
• 🧹 Code Quality: Zero compiler warnings, clean production-ready codebase
• 🧪 198+ Tests: Comprehensive test suite including all v0.4.1 IDE integration features
• 🚀 Production Ready: All tests passing, full IDE support for enhanced developer experience

v0.4.0 - The Developer Experience Edition

• 🔍 NEW: Enhanced Error Messages: Precise line/column error reporting with helpful context and suggestions
• 🐛 NEW: Template Debugging: Complete debugging system with variable tracking and execution step analysis
• 🔥 NEW: Hot Reload: Automatic template reloading during development for faster iteration cycles
• 📊 NEW: Performance Metrics: Built-in performance tracking with execution time analysis
• 🎯 NEW: Intelligent Suggestions: Smart suggestions for template and variable name typos
• 🧪 198+ Tests: Comprehensive test suite including all v0.4.0 developer experience features and v0.4.1 IDE integration
• 🚀 Production Ready: All tests passing, enhanced developer productivity tools

v0.3.4 - The Advanced Features Edition

• 🔄 NEW: Nested Loops: Complete support for nested loops with stack-based parsing ({{for category in shops}}{{for item in category.items}})
• 🔄 NEW: Recursive Includes: Unlimited depth recursive template includes (templates including templates)
• 🛡️ NEW: Path Traversal Protection: Enterprise-grade security preventing ../../../etc/passwd and C:\Windows\System32 attacks
• 🎮 Complete Real-World Demo: Full-featured e-commerce/blog application showcasing ALL features (examples/real_world_demo/)
• 📚 Enhanced Documentation: Complete README overhaul with comprehensive examples and demo application
• 🧪 173+ Tests: Expanded test suite including all v0.3.4 features with comprehensive security testing
• 🚀 Production Ready: All tests passing, zero warnings, full feature demonstration

v0.3.3 - The Warning-Free Edition

• 🧹 Zero Warnings: Complete cleanup of all compiler warnings for production readiness
• 🔧 Code Quality: Enhanced code quality and maintainability improvements
• ✅ Stability: All existing functionality maintained with improved reliability

v0.3.2 - The Enhancement Edition

• 🌐 Enhanced i18n: Improved internationalization with better variable interpolation
• 📝 Smart Pluralization: Advanced plural form handling with locale-aware rules
• 🔢 Math Filter Improvements: Enhanced mathematical operations with better precision
• 🎨 Custom Filter API: Improved API for registering custom filters

v0.3.1 - The Stability Edition

• 🔧 Bug Fixes: Critical fixes for edge cases in template processing
• ⚡ Performance: Optimized parsing and rendering pipeline
• 🧪 Testing: Enhanced test coverage for reliability improvements

v0.3.0 - The Global Sorcery Edition

• 🌐 Internationalization (i18n): Full multi-language support with {{t "key"}} syntax
• 📝 Smart Pluralization: Automatic plural forms with {{plural count "item" "items"}}
• 🔢 Advanced Math Filters: Mathematical operations (add, multiply, divide, percentage, round)
• 🎨 Custom Filter API: Register your own filters with engine.register_filter()
• 🎭 Dual Naming System: Choose between conventional (TemplateEngine) or mystical (RuneEngine) styles
• 🧪 150+ Tests: Comprehensive test suite covering all new features

v0.2.0 - The Advanced Sorcery Edition

• 🏰 Template Inheritance: Advanced layout system with nested inheritance support
• 🔧 Powerful Filters: Built-in filters (upper, lower, currency, truncate, date) with chaining
• 📦 Reusable Macros: Define and invoke template components with parameters
• 🌊 Enhanced Deep Navigation: Unlimited depth dot notation ({{game.player.stats.level}})
• ⚡ Performance Boost: Bytecode compilation, parallel processing, memory mapping
• 🧪 127+ Tests: Comprehensive test coverage including v0.2.0 features
• 🔧 Bug Fixes: Fixed nested layout inheritance and function call error handling
• 🌐 Zero Dependencies: Pure Rust implementation

v0.1.4 (Stability Release)

• 🔧 Fixed nested layout inheritance block replacement boundary calculation
• 🛡️ Enhanced loop error handling for unsupported function calls
• 🔄 Maintained backward compatibility for missing variables in loops
• ✅ All 127 tests passing with comprehensive coverage

v0.1.1 (Security & Testing Release)

• 🛡️ Comprehensive security testing suite
• 🧪 85+ tests with 100% coverage following TDD methodology
• 📚 Complete documentation with TDD development guidelines
• 🔒 Advanced XSS and injection protection
• ⚡ Performance optimizations and stress testing
• 🔴🟢🔵 Strict Test-Driven Development practices implemented

v0.1.0 (Initial Release)

• ✨ Core template engine with Mustache-inspired syntax
• 🔒 XSS-safe HTML escaping by default
• ⚡ Template caching for performance
• 🎯 Support for variables, conditionals, loops, includes, and comments
• 🧪 Comprehensive test suite with high coverage
• 📚 Complete documentation and examples

🗺️ Roadmap

✅ v0.3.0-v0.5.2 - COMPLETED Features

🔧 Filters & I18n (v0.3.0-v0.3.4)

• ✅ i18n Support: {{t "key"}} syntax for translations
• ✅ Pluralization: Smart plural forms based on count
• ✅ Custom Filter Registration: API for user-defined filters
• ✅ Advanced Math Filters: Mathematical operations and formatting

🏗️ Core Engine (v0.3.4)

• ✅ Nested Loops: Stack-based parsing for complex nested structures
• ✅ Recursive Includes: Deep template inclusion hierarchies
• ✅ Path Traversal Protection: Enterprise-grade security features
• ✅ Complete Real-World Demo: Full-featured showcase application

🛠️ Developer Experience (v0.4.0-v0.4.1)

• ✅ Enhanced Error Messages: Line/column numbers and intelligent suggestions
• ✅ Template Debugging: Step-through debugging with variable tracking
• ✅ Hot Reload: Development-time template reloading
• ✅ Language Server Protocol: Complete LSP support for template editing
• ✅ Syntax Highlighting: Semantic token analysis for editor integration
• ✅ Auto-completion: Intelligent variable, filter, and directive completion
• ✅ Real-time Diagnostics: Error squiggles and warnings in editors
• ✅ Hover Information: Variable type and value inspection
• ✅ Go to Definition: Navigate to macro and template definitions

🌐 Ecosystem Integration (v0.5.0-v0.5.2)

• ✅ Async Support: Non-blocking template rendering
• ✅ Web Framework Integration: First-class Axum, Warp, Actix support
• ✅ WASM Compatibility: Browser and edge runtime support
• ✅ CLI Tools: Command-line template processing utilities
• ✅ Performance Monitoring: Advanced metrics collection (v0.5.1)
• ✅ Enterprise Security: Threat classification and audit logging (v0.5.1)

🌟 Why "Mystical-Runic"?

Because templating is basically ancient magic:

• You write mysterious symbols ({{}}) that transform into reality
• Variables appear and disappear like spirits
• One wrong bracket and your entire spell explodes
• Senior developers guard the template secrets like ancient druids
• Documentation is written in a language only the initiated understand
• And just like real magic, it works perfectly until production 🔥

📊 Performance Benchmarks

Mystical-Runic v0.5.2 includes comprehensive performance benchmarks demonstrating enterprise-grade performance:

# Quick performance test
cargo build --release
rustc --edition 2021 benchmarks/simple_benchmark.rs -L target/release/deps --extern mystical_runic=target/release/libmystical_runic.rlib -O && ./simple_benchmark

🎯 Performance Results

• Template Rendering: ~2.7µs per simple template (excellent)
• Filter Processing: ~4.4µs per filter chain (optimized)
• Complex Templates: ~470µs per complex template (scalable)
• Large Data Sets: 215ms per 1000 items (production-ready)

📈 Available Benchmarks

• simple_benchmark.rs - Core functionality performance ✅
• v0_5_2_performance_benchmark.rs - Comprehensive enterprise testing 🚧
• ecosystem_benchmark.rs - Async and CLI integration testing 🌐

See benchmarks/README.md for detailed benchmark documentation and results.

🔗 Links

• 📚 API Documentation: docs.rs/mystical-runic
• 🇫🇷 User Guide: Documentation HTML (français)
• 📦 Crates.io: crates.io/crates/mystical-runic
• 🔧 Repository: github.com/yrbane/mystical-runic
• 🐛 Issues: github.com/yrbane/mystical-runic/issues

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

---

"May your templates be bug-free and your variables always defined."
— Ancient DevOps Proverb

🔮✨ Happy templating! ✨🔮