2 releases
0.0.2 | May 18, 2021 |
---|---|
0.0.1 | May 17, 2021 |
#1653 in Procedural macros
10KB
109 lines
ctjs
Execute JavaScript at compile time to generate Rust code. Both evaluating expressions and custom derives are supported.
eval
use ctjs::eval;
const X: f64 = eval! {
// This is JavaScript
const x = 5;
String(x * Math.PI)
};
assert!(X > 15.0);
assert!(X < 16.0);
Custom Derive
use ctjs::JsMacro;
#[derive(Debug, JsMacro)]
#[js_macro = "fruit_derive"]
enum Fruit {
#[js(name = "granny smith")]
Apple,
Orange,
Pear,
}
fruit_derive! {
js!(
let output = "const _: () = {\n";
output += "use std::fmt::{self, Write};\n";
// name is "Fruit"
output += "impl fmt::Display for " + name + "{\n";
output += "fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {\n";
output += "write!(f, \"{}\", match self {\n";
// ident is "Apple" or "Orange" or "Pear"
for (const { ident, attrs } of item.variants) {
let string = '"' + ident.toLowerCase() + '"';
const kv = ctjs.parse_attrs(attrs);
if (kv.name) {
string = kv.name;
}
output += "Self::" + ident + " => " + string + ",\n";
}
output += "})\n";
output += "}\n}\n};\n";
output
)
}
let fruits = vec![Fruit::Apple, Fruit::Orange, Fruit::Pear];
for fruit in &fruits {
println!("Debug: {:?}, Display: {}", fruit, fruit);
}
assert_eq!(&fruits[0].to_string(), "granny smith");
assert_eq!(&fruits[1].to_string(), "orange");
assert_eq!(&fruits[2].to_string(), "pear");
Current version: 0.0.1
Prior Work
All code licensed as MIT
Dependencies
~5MB
~134K SLoC