3. Abstraction

In everyday language, abstraction is the intellectual operation that consists in retaining only the essential characteristics of something, thus forgetting the other aspects, which are reduced to the level of detail. In programming, the notions of procedure, function, module or software component are all part of the abstraction process, reducing a given piece of programming to the functionality it performs, and allowing certain details of its implementation to be forgotten when it is reused.

Abstraction is a concept closely linked to typing: a type is already in itself the representation of a set of data (the type's "inhabitants") sharing common properties.