Effect system

In computing, an effect system is a formal system which describes the computational effects of computer programs, such as side effects. An effect system can be used to provide a compile-time check of the possible effects of the program. In computing, an effect system is a formal system which describes the computational effects of computer programs, such as side effects. An effect system can be used to provide a compile-time check of the possible effects of the program. The effect system extends the notion of type to have an 'effect' component, which comprises an effect kind and a region. The effect kind describes what is being done, and the region describes with what it is being done. An effect system is typically an extension of a type system. The term 'type and effect system' is sometimes used in this case. Often, a type of a value is denoted together with its effect as type ! effect, where both the type component and the effect component mention certain regions (for example, a type of a mutable memory cell is parameterized by the label of the memory region in which the cell resides).