Editing Slash (punctuation) (section)

====Programming====
The slash is used as a [[#Division|division operator]] in most [[programming language]]s while [[APL (programming language)|APL]] uses it for reduction ([[Fold (higher-order function)|fold]]) and compression ([[Filter (higher-order function)|filter]]). The double slash is used by [[Rexx]] as a [[#Mod|modulo operator]], and [[Python (programming language)|Python]] (starting in version 2.2) uses a double slash for division which rounds (using [[Floor and ceiling functions|floor]]) to an integer.  In [[Raku (programming language)|Raku]] the double slash is used as a "defined-or" alternative to '''||'''. A dot and slash {{angle brackets|./}} is used in [[MATLAB]] and [[GNU Octave]] to indicate an element-by-element division of matrices.

[[comment (computer programming)|Comments]] that begin with {{mono|'''/*'''}} (a slash and an asterisk) and end with {{mono|'''*/'''}} were introduced in [[PL/I]] and subsequently adopted by [[SAS System|SAS]], [[C (programming language)|C]], Rexx, [[C++]], [[Java (programming language)|Java]], [[JavaScript]], [[PHP]], [[Cascading Style Sheets|CSS]], and [[C Sharp (programming language)|C#]]. A double slash {{mono|'''//'''}} is also used by [[C99]], C++, C#, PHP, Java, [[Swift (programming language)|Swift]], [[Pascal (programming_language)|Pascal]] and JavaScript to start a single line comment.

In [[SGML]] and derived languages such as [[HTML]] and [[XML]], a slash is used in closing tags. For example, in HTML, {{mono|&lt;b&gt;}} begins a section of {{strong|bold}} text and {{mono|&lt;/b&gt;}} closes it. In XHTML, slashes are also necessary for "self-closing" elements such as the [[newline]] command {{nowrap|{{mono|&lt;br /&gt;}}}} where HTML has simply {{nowrap|{{mono|&lt;br&gt;}}}}.

In a style originating in the [[Digital Equipment Corporation]] line of operating systems ([[OS/8]], [[RT-11]], [[TOPS-10]], et cetera), [[Windows (operating system)|Windows]], [[DOS]], some [[CP/M]] programs, [[OpenVMS]], and [[OS/2]] all use the slash to indicate [[command-line option]]s. For example, the command {{mono|dir/w}} is understood as using the command [[dir (command)|dir]] ("directory") with the "wide" option. No space is required between the command and the switch; this was the reason for the choice to use backslashes as the path separator since one would otherwise be unable to run a program in a different directory.

Slashes are used as the standard delimiters for [[regular expression]]s, although other characters can be used instead.

[[IBM JCL]] uses a double slash to start each line in a batch job stream except for /* and /&.