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The real power of traits is generic code: write a function once and it works for every conforming type. 🚀

You use a trait as a bound on a generic parameter, promising the type has the methods you call.

Inside square brackets you name a type parameter and the trait it must satisfy, then use it like any type.

Within the function you may call any method the trait guarantees. The compiler knows greet exists on T.

Pass a Dog or a Robot to the same function. Both conform to Greetable, so both are accepted seamlessly.

Generics are not loose. If a type does not satisfy the bound, the compiler refuses it before the program runs.

Mojo specializes generic code at compile time, generating a fast version per type. Flexibility costs no speed.

Without generics you would copy a function for each type. A trait bound lets one definition serve them all, cutting duplication.

A parameter can require several traits at once, ensuring the type has every capability the function needs.

Good Mojo APIs ask for the smallest trait they need. Functions stay flexible while expressing exact requirements.

Trait, conformance, and generics combine: define a contract, implement it, then write one reusable function over it.

Why use a trait bound on a generic function?

Generic functions with a trait bound work across all conforming types, staying type-safe and fast. You now write reusable Mojo! 🎉