functional

pure functional programming does not allow side effects (state modification) except in very isolated and controlled setttings. Permits very advanced optimizations, stemming from the property of equational reasoning. Symbols have demantic definitions with&clear compositionality, which makes the task of writing and debugging much easier.

Some langauges which support FP are: Haskell, ML, Scheme, Miranda, Clean, APL/J

An example of a linear functional on the space C₀(R) of continuous functions on R that tend to 0 is φ(f)=f(0) ("substitution"). An example of a nonlinear functional is the variation of f.

Func"tion*al (?), a.

1.

Pertaining to, or connected with, a function or duty; official.

2. Physiol.

Pertaining to the function of an organ or part, or to the functions in general.

Functional disease Med., a disease of which the symptoms cannot be referred to any appreciable lesion or change of structure; the derangement of an organ arising from a cause, often unknown, external to itself opposed to organic disease, in which the organ itself is affected.

© Webster 1913.