functional

1. A function that takes a function as its argument; more precisely, a function whose argument varies in a space of (real- or complex-valued) functions and whose value belongs to a monodimensional space. · An example of a functional is the definite integration of integrable real functions in a real interval.
2. A scalar-valued linear function on a vector space.
3. An object encapsulating a function pointer (or equivalent).

الجمع functionals