CTTM - Compile Time Template for Rust

CTTM is a simple yet powerful Rust library that allows you to process template files at compile time.

It converts your templates into native Rust code, eliminating runtime overhead for template parsing.

Features

• Compile-Time Processing
• Simple Syntax
• Zero Dependencies at Runtime

How It Works

• You create template files with a .ct extension. These files contain a mix of plain text and embedded Rust logic.
• A build.rs script in your project uses CTTM to find and compile all .ct files into a single Rust module.
• In your application code, you use the cttm::import!() macro to include the generated module.
• You can then call your templates as if they were regular Rust functions.

Getting Started

1. Update Cargo.toml

[build-dependencies]
cttm = { version = "*", features = ["build"] }

[dependencies]
cttm = "*"

2. Create build.rs

// build.rs
use std::process::exit;

fn main() {
    // Compile all template files ending in .ct in the "templates" directory
    if let Err(e) = cttm::compile_all("templates/**/*.ct") {
        eprintln!("{}", e);
        exit(1);
    }
}

3. Write Your Templates

Create a directory for your templates (e.g., templates/). A template file consists of two parts separated by ---:

1. Prologue: Defines the function signature (arguments).
2. Body: The template content.

Example: templates/greeting.ct

name: &str
---
#if name == "World" {
    Hello, World!
#} else {
    Hi, ${name}!
#}

Example: templates/star.ct

n: usize
---
#for i in 1..=n {
${ "*".repeat(i) }
#}

4. Use Templates in Your Code

In your main.rs or any other module, import the generated template functions and call them.

// src/main.rs
use std::io::stdout;

// Import the generated module (cttm::tpl::*)
::cttm::import!();

fn main() {
    // Call the greeting.ct template
    cttm::tpl::greeting(&mut stdout(), "Rust").unwrap();
    println!(); // for a newline

    // Call the star.ct template
    cttm::tpl::star(&mut stdout(), 5).unwrap();
}

The module path will be cttm::tpl::<template_name>, where <template_name> is the filename of your template without the .ct extension.

Template Syntax

• Prologue: The section before --- declares the arguments for the generated function.
• Rust Code Lines: Any line starting with # is treated as a line of Rust code (e.g., for loops, if/else conditions, variable assignments).
• Expression Interpolation: Use ${...} to embed the result of a Rust expression into the output.
• Escaping: To print a literal # at the beginning of a line, escape it with a backslash: \#. To print a literal $, use \$.

License

This project is licensed under the MIT License.