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_archive/rhai_engine/rhaibook/rust/generic.md

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+Register a Generic Rust Function
+================================
+
+{{#include ../links.md}}
+
+```admonish warning.small "No monomorphization"
+
+Due to its dynamic nature, Rhai cannot monomorphize generic functions automatically.
+
+Monomorphization of generic functions must be performed manually.
+```
+
+Rust generic functions can be used in Rhai, but separate instances for each concrete type must be
+registered separately.
+
+This essentially _overloads_ the function with different parameter types as Rhai does not natively
+support generics but Rhai does support _[function overloading]_.
+
+The example below shows how to register multiple functions (or, in this case, multiple overloaded
+versions of the same function) under the same name.
+
+```rust
+use std::fmt::Display;
+
+use rhai::Engine;
+
+fn show_it<T: Display>(x: &mut T) {
+    println!("put up a good show: {x}!");
+}
+
+let mut engine = Engine::new();
+
+engine.register_fn("print", show_it::<i64>)
+      .register_fn("print", show_it::<bool>)
+      .register_fn("print", show_it::<ImmutableString>);
+```