Functional Programming

Functional versus other programming paradigms the functional programming approach differs from the traditional and current mainstream approaches to programming: it is more mathematical in flavor and amenable to logical proof (look here for a comparison of paradigms)

Functional Programming

	Functional versus other programming paradigms
	A high-level, abstract style of programming functional programs are much more concise than their traditional counterparts: whether this makes them easier to understand is a matter of training and "mathematical sophistication"

Functional Programming

	Functional versus other programming paradigms
	A high-level, abstract style of programming
	Functional purity = referential transparency a crucial aspect of purely functional programming languages is that they admit substitution of equal values in any (syntactically valid) context: this facilitates proofs about programs

Functional Programming

	Functional versus other programming paradigms
	A high-level, abstract style of programming
	Functional purity = referential transparency
	Algebraic data types many functional languages support the definition of initial algebraic data types: these are a generalization of context-free term structures, but with overt tags on alternatives

Functional Programming

	Functional versus other programming paradigms
	A high-level, abstract style of programming
	Functional purity = referential transparency
	Algebraic data types
	Higher-order functions much of the power of functional languages comes from the use of higher-order functions, i.e., functions which take as arguments or return other functions

Functional Programming

	Functional versus other programming paradigms
	A high-level, abstract style of programming
	Functional purity = referential transparency
	Algebraic data types
	Higher-order functions
	Polymorphism and other complex types in order to make programming less tedious, type inference systems allow type to remain implicit when possible; programs are nevertheless guaranteed statically correct wrt types (most typed languages use quantified types and other sophisticated features to make this possible)

Functional Programming

	Functional versus other programming paradigms
	A high-level, abstract style of programming
	Functional purity = referential transparency
	Algebraic data types
	Higher-order functions
	Polymorphism and other complex types
	The Haskell class system the Haskell programming language also features a class system which allows abstract specification of type signatures and instantiation of concrete types (NB: no axioms, though!)