chore: Add Janet native module example

Cargo.toml

@@ -76,3 +76,8 @@ members = ["janetrs_macros", "janetrs_version"]
 [[example]]
 name = "hello_world"
 required-features = ["amalgation"]
+
+[[example]]
+name = "janet_native_module"
+crate-type = ["cdylib", "staticlib"]
+required-features = ["amalgation"]

examples/janet_native_module.rs

@@ -0,0 +1,34 @@
+//! For a more complete example to create a Janet package with jpm, check out [this
+//! template repository](https://github.com/GrayJack/rust-janet-module-template)
+
+use janetrs::{declare_janet_mod, janet_fn, jpanic, Janet, JanetTuple, TaggedJanet};
+
+/// (template/hello)
+///
+/// Rust say hello
+#[janet_fn(arity(fix(0)))]
+pub fn rust_hello(_args: &mut [Janet]) -> Janet {
+    println!("Hello from Rust!");
+    Janet::nil()
+}
+
+/// (template/chars)
+///
+/// If the argument is a buffer or string, return a array or tuple of the chars of the
+/// argument, else return nil
+#[janet_fn(arity(fix(1)))]
+pub fn chars(args: &mut [Janet]) -> Janet {
+    match args[0].unwrap() {
+        TaggedJanet::Buffer(b) => b.chars().collect::<JanetTuple>().into(),
+        TaggedJanet::String(s) => s.chars().collect::<JanetTuple>().into(),
+        _ => jpanic!(
+            "bad slot #0, expected string|buffer, got {}",
+            args[0].kind()
+        ),
+    }
+}
+
+declare_janet_mod!("template";
+    {"hello", rust_hello},
+    {"chars", chars},
+);