Meaning of existential type | Babel Free

Definitions

1. A type that hides the underlying concrete type(s).
2. Used other than figuratively or idiomatically: see existential, type.

Examples

“Existential types are fundamentally no more complicated than universal types (in fact, we will see⟳ in §24.3 that existentials can straightforwardly be encoded in terms of universals).”

“Scala 2 supported existential types, a way of abstracting over types. They let⟳ you assert that some type⟳ exists without specifying exactly what it is, usually because you don't know⟳ what it is and you don't need⟳ to know⟳ it in the current context.”

“This behavior is what gives existential types their name⟳: we are asserting that there exists some concrete type⟳ that matches the signature, and we leave⟳ it up to the compiler to find⟳ what that type⟳ is.”

“This is an existential type⟳ of anxiety that stems from the feeling that we are not at home in this world.”

“He was an existential type⟳ dude with no belongings to speak⟳ of. He didn't care about tomorrow; he lived in the moment. He was always reading a book; quiet yet explosive.”

CEFR level