Editing Literate programming (section)

{{Short description|A programming approach of software development}}
{{Use American English|date=June 2024}}
{{Use mdy dates|cs1-dates=ll|date=June 2024}}
[[File:Literate Programming book cover.jpg|thumb|''Literate Programming'' by [[Donald Knuth]] is the seminal book on literate programming.]]
'''Literate programming''' is a [[programming paradigm]] introduced in 1984 by [[Donald Knuth]] in which a [[computer program]] is given as an explanation of how it works in a [[natural language]], such as English, interspersed (embedded) with [[Snippet (programming)|snippets]] of [[Macro (computer science)|macros]] and traditional [[source code]], from which [[Compiler|compilable]] source code can be generated.<ref name="TCJ_LP">{{note label|TCJ_LP||v}}{{note label|TCJ_LP||w}}{{note label|TCJ_LP||x}}{{note label|TCJ_LP||y}}{{note label|TCJ_LP||z}}{{Cite journal |last=Knuth |first=Donald E. |author-link=Donald Knuth |date=1984 |title=Literate Programming |url= http://www.literateprogramming.com/knuthweb.pdf |journal=[[The Computer Journal]] |publisher=[[British Computer Society]] |volume=27 |issue=2 |pages=97–111 |doi=10.1093/comjnl/27.2.97 |access-date=January 4, 2009 |doi-access=free}}</ref> The approach is used in [[scientific computing]] and in [[data science]] routinely for [[reproducible research]] and [[open access]] purposes.<ref>{{Cite journal |last=Schulte |first=Eric |date=2012 |title=A Multi-Language Computing Environment for Literate Programming and Reproducible Research |url= https://www.jstatsoft.org/article/view/v046i03/v46i03.pdf |url-status=live |journal=Journal of Statistical Software |volume=46 |issue=3 |doi=10.18637/jss.v046.i03 |archive-url= https://web.archive.org/web/20141109113411/https://www.jstatsoft.org/article/view/v046i03/v46i03.pdf |archive-date=November 9, 2014 |access-date=May 30, 2020 |doi-access=free}}</ref> Literate programming tools are used by millions of programmers today.<ref>{{Cite conference |last=Kery |first=Mary Beth |date=April 2018 |title=The Story in the Notebook: Exploratory Data Science using a Literate Programming Tool |book-title=CHI '18: Proceedings of the 2018 CHI Conference on Human Factors in Computing Systems |publisher=[[Association for Computing Machinery]] |pages=1–11 |doi=10.1145/3173574.3173748}}</ref>

The literate programming paradigm, as conceived by Donald Knuth, represents a move away from writing computer programs in the manner and order imposed by the compiler, and instead gives [[programmer]]s macros to develop programs in the order demanded by the logic and flow of their thoughts.<ref>{{block quote|I had the feeling that top-down and bottom-up were opposing methodologies: one more suitable for program exposition and the other more suitable for program creation. But after gaining experience with WEB, I have come to realize that there is no need to choose once and for all between top-down and bottom-up, because a program is best thought of as a web instead of a tree. A hierarchical structure is present, but the most important thing about a program is its structural relationships. A complex piece of software consists of simple parts and simple relations between those parts; the programmer's task is to state those parts and those relationships, in whatever order is best for human comprehension not in some rigidly determined order like top-down or bottom-up. |author=[[Donald Knuth|Donald E. Knuth]] |source=''Literate Programming''{{ref label|TCJ_LP|1|v}} }}</ref> Literate programs are written as an exposition of logic in more [[natural language]] in which [[Macro (computer science)|macros]] are used to hide abstractions and traditional [[source code]], more like the text of an [[essay]]. 

Literate programming (LP) tools are used to obtain two representations from a source file: one understandable by a compiler or interpreter, the "tangled" code, and another for viewing as formatted [[documentation]], which is said to be "woven" from the literate source.<ref name="ObliqueScottReference">If one remembers that the first version of the tool was called WEB, the amusing literary reference hidden by Knuth in these names becomes obvious: "Oh, what a tangled web we weave when first we practise to deceive" — [[Sir Walter Scott]], in Canto VI, Stanza 17 of ''[[Marmion (poem)|Marmion]]'' (1808) an epic poem about the [[Battle of Flodden]] in 1513. – the actual citation appeared as an epigraph in a May 1986 article by Jon Bentley and Donald Knuth in one of the classical "Programming Pearls" columns in ''Communications of the ACM'', vol. 29, no. 5, p. 365.</ref> While the first generation of literate programming tools were [[computer language]]-specific, the later ones are [[Language-independent specification|language-agnostic]] and exist beyond the individual programming languages.