Tacit programming: Difference between revisions

Revision as of 21:44, 14 October 2019

Revision as of 17:41, 30 November 2019

Line 2:

'''Tacit programming''', also called '''point-free style''', is a [[programming paradigm]] in which function definitions do not identify the [[parameter (computer science)|arguments]] (or "points") on which they operate. Instead the definitions merely [[function composition (computer science)|compose]] other functions, among which are [[Combinatory logic|combinators]] that manipulate the arguments. Tacit programming is of theoretical interest, because the strict use of composition results in programs that are well adapted for [[Equational logic|equational]] reasoning.<ref name="cunha2005">Manuel Alcino Pereira da Cunha (2005) [http://hdl.handle.net/1822/2869 Point-free Program Calculation]</ref> It is also the natural style of certain [[programming languages]], including [[APL (programming language)|APL]] and its derivatives,<ref>W. Neville Holmes, ed. (2006) ''Computers and People''</ref> and [[concatenative programming language|concatenative languages]] such as [[Forth (programming language)|Forth]]. The lack of argument naming gives point-free style a reputation of being unnecessarily obscure, hence the epithet "pointless style".<ref name="cunha2005"/>

[[UNIXUnix]] [[Command-line interface|scripting]] uses the paradigm with [[Pipeline (Unix)|pipes]].

For example, a sequence of operations in an [[applicative language]] such as the following [[Python (programming language)|Python]] code:

<source lang="python">

def example(x):

y = foo(x)

z = bar(y)

w = baz(z)

return w

</source>

... is written in point-free style as the composition of a sequence of functions, without parameters:<ref>{{cite web | url=http://concatenative.org/wiki/view/Concatenative%20language/Name%20code%20not%20values | title=Name code not values | publisher=Concatenative.org | accessdate=13 September 2013}}</ref>

Line 116:

</source>

===UNIXUnix pipeline===

{{main|Pipeline (Unix)}}

In UNIXUnix scripting the functions are computer programs which receive data from [[Standard streams|standard input]] and send the results to [[Standard streams|standard output]]. For example,

<source lang="bash">

sort | uniq -c | sort -rn