[][src]Crate t4rust_derive


t4rust is a minimal templating engine, inspired by the T4 syntax.


A simple example how to create a template.

use t4rust_derive::Template;

// Add this attribute to use a template
// Specify the path to the template file here
#[TemplatePath = "./examples/doc_example1.tt"]
// Add this attribute if you want to get debug parsing information
// This also enables writing temporary files, you might get better error messages.
struct Example {
    // Add fields to the struct you want to use in the template
    name: String,
    food: String,
    num: i32,

fn main() {
    // Generate your template by formating it.
    let result = format!("{}", Example { name: "Splamy".into(), food: "Cake".into(), num: 3 });
    println!("{}", result);


Hello From Template!
My Name is: <# write!(_fmt, "{}", self.name)?; #>
I like to eat <#= self.food #>.
<# for num in 0..self.num { #>Num:<#= num + 1 #>
<# } #>


Hello From Template!
My Name is: Splamy
I like to eat Cake.


You can simply write rust code within code blocks.

Code is written within <# and #> blocks. If you want to write a <# in template text without starting a code block simply write it twice: <#<#. Same goes for the #> in code blocks. You dont need to duplicate the <# within code blocks and #> not in template text blocks.

You can use <#= expr #> to print out a single expression.

Maybe you noticed the magical _fmt in the template. This variable gives you access to the formatter and e.g. enables you to write functions in your template. <# write!(_fmt, "{}", self.name)?; #> is equal to <#= self.name #>.

Warning: Make sure to never create a variable called _fmt! You will get weird compiler errors.



Use the escape directive in your .tt file:

<#@ escape function="escape_html" #>`

And a function with this signature in your code:

fn escape_html(s: &str) -> String {
    todo!(); /* Your escaping code here */

All expression blocks (e.g. <#= self.name #>) will call the escape function before inserted.

You can redeclare this directive as many times and where you want in your template to change or disable (with function="") the escape function.

Derive Macros