In programming languages, an abstract type, unlike Concrete class is a type in a nominative type system which cannot be instantiated. (However, it may have concrete subtypes that do have instances.) An abstract type may have no implementation, or an incomplete implementation. It may include abstract methods or abstract properties that are shared by its subtypes.
A type that is not abstract is called a concrete type.
In many object oriented programming languages, abstract types are known as abstract base classes. In some languages, abstract types with no implementation are known as interfaces. Other names for language features that are (or may be) used to implement abstract types include traits, mixins, flavors, or roles.
Read more about Abstract Type: Signifying Abstract Types, Use of Abstract Types
Famous quotes containing the words abstract and/or type:
“For although memories, of a season, for example,
Melt into a single snapshot, one cannot guard, treasure
That stalled moment. It too is flowing, fleeting;
It is a picture of flowing, scenery, though living, mortal,
Over which an abstract action is laid out in blunt,
Harsh strokes.”
—John Ashbery (b. 1927)
““... In truth I find it ridiculous that a man of his intelligence suffer over this type of person, who is not even interesting, for she is said to be foolish”, she added with all the wisdom of people who are not in love, who find that a sensible man should only be unhappy over a person who is worthwhile; it is almost tantamount to being surprised that anyone deign having cholera for having been infected with a creature as small as the vibrio bacilla.”
—Marcel Proust (1871–1922)