Macro json 

json!() { /* proc-macro */ }

Convert JSON-like Rust tokens into a &'static str at compile time.

Accepts a superset of JSON syntax using Rust token trees:

• Objects: { "key": value, ... }
• Arrays: [value, ...]
• Strings: "hello"
• Numbers: 42, 3.14, -1
• Booleans: true, false
• Null: null
• Trailing commas are stripped

const CFG: &str = ktstr::json!({
    "layers": [{
        "name": "batch",
        "kind": { "Grouped": { "cpus_range": [0, 4] } },
    }],
});