A type signature defines the inputs and outputs for a function or method. A type signature includes at least the function name and the number of its parameters. In some programming languages, it may also specify the function's return type or the types of its parameters. Jump to: navigation, search In computer science, a subroutine (function, procedure, or subprogram) is a sequence of code which performs a specific task, as part of a larger program, and is grouped as one or more statement blocks; such code is sometimes collected into software libraries. ... Used mainly in object-oriented programming, the term method refers to a piece of code that is exclusively associated either with a class (called class methods or static methods) or with an object (called instance methods). ...

Haskell

A type signature in Haskell is written, generally, in the following format:

 functionName :: arg1Type -> arg2Type -> ... -> argNType 

Notice that the final output can be regarded as an argument. This is a consequence of currying. That is, given a function that had one argument supplied, but takes in two inputs, the function is "curried" and becomes a function of one argument -- the one that is not supplied. In computer science, currying is the technique of transforming a function taking multiple arguments into a function that takes a single argument (the first of the arguments to the original function) and returns a new function that takes the remainder of the arguments and returns the result. ...

The actual type specifications can consist of an actual type, such as Integer, or a type variable that is used in parametric polymorphic functions, such as "a", or "b", or "anyType". So we can write something like: In computer science and mathematics, a variable is a symbol denoting a quantity or symbolic representation. ... In computer science, polymorphism is the idea of allowing the same code to be used with different types, resulting in more general and abstract implementations. ... In computer science, a subroutine (function, procedure, or subprogram) is a sequence of code which performs a specific task, as part of a larger program, and is grouped as one, or more, statement blocks; such code is sometimes collected into software libraries. ...

 functionName :: a -> a -> ... -> a 

Since Haskell supports higher-order functions, functions can be passed as arguments, and this is written as: In mathematics and computer science, higher-order functions are functions which can take other functions as arguments, and may also return functions as results. ...

 functionName :: (a -> a) -> a 

This function takes in a function with type signature a -> a, and returns data of type "a" out.

Java

In the Java virtual machine, so-called internal type signatures are used to identify methods and classes at the level of the virtual machine code. Jump to: navigation, search A Java Virtual Machine or JVM is a virtual machine that runs Java byte code. ...

Example: The method String String.substring(int, int) is represented as java/lang/String/substring(II)Ljava/lang/String;