thedustinmiller / serp Goto Github PK

The rust format! macro requires the string template to be passed as a string literal at compile time. This crate uses the well known template language handlebars to allow for everything to be passed at runtime. Using the entirety of handlebars is definitely overkill for simply making an ergonomic string interpolation function, but I'm far more confident in the correctness of a well tested and popular library than I would be if I rolled my own. I make no modifications to the syntax of handlebars, so unfortunately I can't replicate the syntax of format! exactly.

You can initialize an empty template with Template::new() and then modify the template and/or push new key/value pairs. This isn't much more succinct than handlebars directly, but it's here for completeness.

let mut s = Serp::default();
s.template = "{{sample}} {{string}}".to_string();
s.push("sample".into(), "hello".into());
s.push("string".into(), "world".into());

assert_eq!(s.format(), "hello world");

The primary function is serp which takes a template as a String and a HashMap<String, String> of key/value pairs.

let template = "Hello, {{name}}".to_string();
let map = HashMap::from([("name".into(), "world".into())]);

assert_eq!(serp(&template, &map), "Hello, world".to_string());

The final methods are the final product, shorthand ways to use serp. t takes a template as a &str and an array of key/value tuples as a &[(&str, &str)]

let t = t("{{sample}} {{string}}", &[("sample", "Hello"), ("string", "World")]);
assert_eq!(t, "Hello World");

Finally, the laziest example, which uses a little convention to be both standard handlebars and succinct. a simply takes a template as a &str and an array of strings in &[&str]. The template brackets are numbered, 0 indexed.

let a = a("{{0}} {{1}}", &["Hello", "World"]);
assert_eq!(a, "Hello World");

Dual licensed under MIT and Apache 2.0