Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Cut (logic programming)
open-in-new
<p>The cut, in <a href="/facts/Prolog/r5h66Qh1">Prolog</a>, is a <a href="/facts/Goal/N5UtLKVk">goal</a>, written as !, which always succeeds but cannot be backtracked. Cuts can prevent unwanted <a href="/facts/Backtracking/Jm9vDUk8">backtracking</a>, which could add unwanted solutions and/or space/time overhead to a query. </p><p>The cut should be used sparingly. While cuts can be inserted into code containing errors, if a test is unnecessary because a cut has guaranteed that it is true, it is good practice to say so in a comment at the appropriate place. </p><p>Some programmers call the cut a controversial control facility because it was added for efficiency reasons only and is not a <a href="/facts/Well-formed_formula/YpTVlzuj">logical formula</a>. </p>