In Rust programming language, Combinators are a set of functional programming constructs that allows for composing different functional operations into a single function. Combinators are useful in building expressive and robust code, as they provide a concise way to write complex code.

There are several types of combinators in Rust, including Result Combinators, Iterator Combinators, and Future Combinators. Each of these allows for chaining different functional operations in a sequence, each producing a new output that serves as an input to the next operation.

• Result Combinators: These are functions used to transform and manipulate results from functions that return a Result type in Rust. Examples include map(), and_then(), and unwrap_or().

• Iterator Combinators: These are methods used to chain different operations to transform and reduce an iterator. Popular iterator combinators include map(), filter(), and fold().

• Future Combinators: These are methods used to compose asynchronous operations to produce a desired output. Popular future combinators include map(), and_then(), and join().

Combinators provide an efficient and expressive way to handle multiple operations, and their use can greatly reduce the complexity of Rust code.