See all glossary terms

Function Signature

A function's signature is the combination of its name, parameters, and return type. It's what defines how you can call the function, and what you can expect from it.
For example, the signature of
func add(a: int, b: int) -> int:
  return a + b
is (a: int, b: int) -> int. This means that the function takes two integers as arguments, and returns an integer.
The name "signature" comes from the idea that the function's name and parameters are unique and identifying.
When discussing a function's signature in conversation, you can sometimes use a format like (int, int) -> int to make it more concise.

See Also

Related terms in the Glossary