Declarative programming: Difference between revisions

Revision as of 03:35, 2 July 2024

Revision as of 09:13, 31 July 2024

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===Lisp===

[[Lisp (programming language) |Lisp]] is a family of programming languages loosely inspired by mathematical notation and [[Alonzo Church]]'s [[lambda calculus]]. Some dialects, likesuch as [[Common Lisp]], are primarily imperative but support functional programming. Others, likesuch as [[Scheme (programming language)|Scheme]], are designed for functional programming.

In Scheme, the [[factorial]] function can be defined as follows:

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This defines the factorial function using its recursive definition. In contrast, it is more typical to define a procedure for an imperative language.

In lisps and lambda calculus, functions are generally [[first-class citizen |first-class citizens]]s. Loosely, this means that functions can be inputs and outputs for other functions. This can simplify the definition of some functions.

For example, writing a function to output the first n [[Squaresquare number|square numbers]]s in [[Racket (programming language)|Racket]] can be done accordingly:

<syntaxhighlight lang=scheme>

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</syntaxhighlight>

The [[Map (higher-order function) |map]] function accepts a function and a list; the output is a list of results of the input function on each element of the input list.

===ML===