This file is indexed.

/usr/share/doc/racket/reference/mpairs.html is in racket-doc 6.7-3.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"/><title>4.10&nbsp;Mutable Pairs and Lists</title><link rel="stylesheet" type="text/css" href="../scribble.css" title="default"/><link rel="stylesheet" type="text/css" href="extras.css" title="default"/><link rel="stylesheet" type="text/css" href="../racket.css" title="default"/><link rel="stylesheet" type="text/css" href="../manual-style.css" title="default"/><link rel="stylesheet" type="text/css" href="../manual-racket.css" title="default"/><link rel="stylesheet" type="text/css" href="../manual-racket.css" title="default"/><link rel="stylesheet" type="text/css" href="../doc-site.css" title="default"/><script type="text/javascript" src="../scribble-common.js"></script><script type="text/javascript" src="../manual-racket.js"></script><script type="text/javascript" src="../manual-racket.js"></script><script type="text/javascript" src="../doc-site.js"></script><script type="text/javascript" src="../local-redirect/local-redirect.js"></script><script type="text/javascript" src="../local-redirect/local-user-redirect.js"></script><!--[if IE 6]><style type="text/css">.SIEHidden { overflow: hidden; }</style><![endif]--></head><body id="doc-racket-lang-org"><div class="tocset"><div class="tocview"><div class="tocviewlist tocviewlisttopspace"><div class="tocviewtitle"><table cellspacing="0" cellpadding="0"><tr><td style="width: 1em;"><a href="javascript:void(0);" title="Expand/Collapse" class="tocviewtoggle" onclick="TocviewToggle(this,&quot;tocview_0&quot;);">&#9658;</a></td><td></td><td><a href="index.html" class="tocviewlink" data-pltdoc="x"><span style="font-weight: bold">The Racket Reference</span></a></td></tr></table></div><div class="tocviewsublisttop" style="display: none;" id="tocview_0"><table cellspacing="0" cellpadding="0"><tr><td align="right">1&nbsp;</td><td><a href="model.html" class="tocviewlink" data-pltdoc="x">Language Model</a></td></tr><tr><td align="right">2&nbsp;</td><td><a href="notation.html" class="tocviewlink" data-pltdoc="x">Notation for Documentation</a></td></tr><tr><td align="right">3&nbsp;</td><td><a href="syntax.html" class="tocviewlink" data-pltdoc="x">Syntactic Forms</a></td></tr><tr><td align="right">4&nbsp;</td><td><a href="data.html" class="tocviewselflink" data-pltdoc="x">Datatypes</a></td></tr><tr><td align="right">5&nbsp;</td><td><a href="structures.html" class="tocviewlink" data-pltdoc="x">Structures</a></td></tr><tr><td align="right">6&nbsp;</td><td><a href="mzlib_class.html" class="tocviewlink" data-pltdoc="x">Classes and Objects</a></td></tr><tr><td align="right">7&nbsp;</td><td><a href="mzlib_unit.html" class="tocviewlink" data-pltdoc="x">Units</a></td></tr><tr><td align="right">8&nbsp;</td><td><a href="contracts.html" class="tocviewlink" data-pltdoc="x">Contracts</a></td></tr><tr><td align="right">9&nbsp;</td><td><a href="match.html" class="tocviewlink" data-pltdoc="x">Pattern Matching</a></td></tr><tr><td align="right">10&nbsp;</td><td><a href="control.html" class="tocviewlink" data-pltdoc="x">Control Flow</a></td></tr><tr><td align="right">11&nbsp;</td><td><a href="concurrency.html" class="tocviewlink" data-pltdoc="x">Concurrency and Parallelism</a></td></tr><tr><td align="right">12&nbsp;</td><td><a href="Macros.html" class="tocviewlink" data-pltdoc="x">Macros</a></td></tr><tr><td align="right">13&nbsp;</td><td><a href="input-and-output.html" class="tocviewlink" data-pltdoc="x">Input and Output</a></td></tr><tr><td align="right">14&nbsp;</td><td><a href="security.html" class="tocviewlink" data-pltdoc="x">Reflection and Security</a></td></tr><tr><td align="right">15&nbsp;</td><td><a href="os.html" class="tocviewlink" data-pltdoc="x">Operating System</a></td></tr><tr><td align="right">16&nbsp;</td><td><a href="memory.html" class="tocviewlink" data-pltdoc="x">Memory Management</a></td></tr><tr><td align="right">17&nbsp;</td><td><a href="unsafe.html" class="tocviewlink" data-pltdoc="x">Unsafe Operations</a></td></tr><tr><td align="right">18&nbsp;</td><td><a href="running.html" class="tocviewlink" data-pltdoc="x">Running Racket</a></td></tr><tr><td align="right"></td><td><a href="doc-bibliography.html" class="tocviewlink" data-pltdoc="x">Bibliography</a></td></tr><tr><td align="right"></td><td><a href="doc-index.html" class="tocviewlink" data-pltdoc="x">Index</a></td></tr></table></div></div><div class="tocviewlist"><table cellspacing="0" cellpadding="0"><tr><td style="width: 1em;"><a href="javascript:void(0);" title="Expand/Collapse" class="tocviewtoggle" onclick="TocviewToggle(this,&quot;tocview_1&quot;);">&#9660;</a></td><td>4&nbsp;</td><td><a href="data.html" class="tocviewlink" data-pltdoc="x">Datatypes</a></td></tr></table><div class="tocviewsublist" style="display: block;" id="tocview_1"><table cellspacing="0" cellpadding="0"><tr><td align="right">4.1&nbsp;</td><td><a href="booleans.html" class="tocviewlink" data-pltdoc="x">Booleans and Equality</a></td></tr><tr><td align="right">4.2&nbsp;</td><td><a href="numbers.html" class="tocviewlink" data-pltdoc="x">Numbers</a></td></tr><tr><td align="right">4.3&nbsp;</td><td><a href="strings.html" class="tocviewlink" data-pltdoc="x">Strings</a></td></tr><tr><td align="right">4.4&nbsp;</td><td><a href="bytestrings.html" class="tocviewlink" data-pltdoc="x">Byte Strings</a></td></tr><tr><td align="right">4.5&nbsp;</td><td><a href="characters.html" class="tocviewlink" data-pltdoc="x">Characters</a></td></tr><tr><td align="right">4.6&nbsp;</td><td><a href="symbols.html" class="tocviewlink" data-pltdoc="x">Symbols</a></td></tr><tr><td align="right">4.7&nbsp;</td><td><a href="regexp.html" class="tocviewlink" data-pltdoc="x">Regular Expressions</a></td></tr><tr><td align="right">4.8&nbsp;</td><td><a href="keywords.html" class="tocviewlink" data-pltdoc="x">Keywords</a></td></tr><tr><td align="right">4.9&nbsp;</td><td><a href="pairs.html" class="tocviewlink" data-pltdoc="x">Pairs and Lists</a></td></tr><tr><td align="right">4.10&nbsp;</td><td><a href="" class="tocviewselflink" data-pltdoc="x">Mutable Pairs and Lists</a></td></tr><tr><td align="right">4.11&nbsp;</td><td><a href="vectors.html" class="tocviewlink" data-pltdoc="x">Vectors</a></td></tr><tr><td align="right">4.12&nbsp;</td><td><a href="boxes.html" class="tocviewlink" data-pltdoc="x">Boxes</a></td></tr><tr><td align="right">4.13&nbsp;</td><td><a href="hashtables.html" class="tocviewlink" data-pltdoc="x">Hash Tables</a></td></tr><tr><td align="right">4.14&nbsp;</td><td><a href="sequences_streams.html" class="tocviewlink" data-pltdoc="x">Sequences and Streams</a></td></tr><tr><td align="right">4.15&nbsp;</td><td><a href="dicts.html" class="tocviewlink" data-pltdoc="x">Dictionaries</a></td></tr><tr><td align="right">4.16&nbsp;</td><td><a href="sets.html" class="tocviewlink" data-pltdoc="x">Sets</a></td></tr><tr><td align="right">4.17&nbsp;</td><td><a href="procedures.html" class="tocviewlink" data-pltdoc="x">Procedures</a></td></tr><tr><td align="right">4.18&nbsp;</td><td><a href="void.html" class="tocviewlink" data-pltdoc="x">Void</a></td></tr><tr><td align="right">4.19&nbsp;</td><td><a href="undefined.html" class="tocviewlink" data-pltdoc="x">Undefined</a></td></tr></table></div></div><div class="tocviewlist"><table cellspacing="0" cellpadding="0"><tr><td style="width: 1em;"><a href="javascript:void(0);" title="Expand/Collapse" class="tocviewtoggle" onclick="TocviewToggle(this,&quot;tocview_2&quot;);">&#9658;</a></td><td>4.10&nbsp;</td><td><a href="" class="tocviewselflink" data-pltdoc="x">Mutable Pairs and Lists</a></td></tr></table><div class="tocviewsublistbottom" style="display: none;" id="tocview_2"><table cellspacing="0" cellpadding="0"><tr><td align="right">4.10.1&nbsp;</td><td><a href="#%28part._.Mutable_.Pair_.Constructors_and_.Selectors%29" class="tocviewlink" data-pltdoc="x">Mutable Pair Constructors and Selectors</a></td></tr></table></div></div></div><div class="tocsub"><div class="tocsubtitle">On this page:</div><table class="tocsublist" cellspacing="0"><tr><td><span class="tocsublinknumber">4.10.1<tt>&nbsp;</tt></span><a href="#%28part._.Mutable_.Pair_.Constructors_and_.Selectors%29" class="tocsubseclink" data-pltdoc="x">Mutable Pair Constructors and Selectors</a></td></tr><tr><td><a href="#%28def._%28%28quote._~23~25kernel%29._mpair~3f%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">mpair?</span></span></a></td></tr><tr><td><a href="#%28def._%28%28quote._~23~25kernel%29._mcons%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">mcons</span></span></a></td></tr><tr><td><a href="#%28def._%28%28quote._~23~25kernel%29._mcar%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">mcar</span></span></a></td></tr><tr><td><a href="#%28def._%28%28quote._~23~25kernel%29._mcdr%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">mcdr</span></span></a></td></tr><tr><td><a href="#%28def._%28%28quote._~23~25kernel%29._set-mcar%21%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">set-<wbr></wbr>mcar!</span></span></a></td></tr><tr><td><a href="#%28def._%28%28quote._~23~25kernel%29._set-mcdr%21%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">set-<wbr></wbr>mcdr!</span></span></a></td></tr></table></div></div><div class="maincolumn"><div class="main"><div class="navsettop"><span class="navleft"><form class="searchform"><input class="searchbox" style="color: #888;" type="text" value="...search manuals..." title="Enter a search string to search the manuals" onkeypress="return DoSearchKey(event, this, &quot;6.7&quot;, &quot;../&quot;);" onfocus="this.style.color=&quot;black&quot;; this.style.textAlign=&quot;left&quot;; if (this.value == &quot;...search manuals...&quot;) this.value=&quot;&quot;;" onblur="if (this.value.match(/^ *$/)) { this.style.color=&quot;#888&quot;; this.style.textAlign=&quot;center&quot;; this.value=&quot;...search manuals...&quot;; }"/></form>&nbsp;&nbsp;<a href="../index.html" title="up to the documentation top" data-pltdoc="x" onclick="return GotoPLTRoot(&quot;6.7&quot;);">top</a></span><span class="navright">&nbsp;&nbsp;<a href="pairs.html" title="backward to &quot;4.9 Pairs and Lists&quot;" data-pltdoc="x">&larr; prev</a>&nbsp;&nbsp;<a href="data.html" title="up to &quot;4 Datatypes&quot;" data-pltdoc="x">up</a>&nbsp;&nbsp;<a href="vectors.html" title="forward to &quot;4.11 Vectors&quot;" data-pltdoc="x">next &rarr;</a></span>&nbsp;</div><h4 x-source-module="(lib &quot;scribblings/reference/reference.scrbl&quot;)" x-source-pkg="racket-doc" x-part-tag="&quot;mpairs&quot;">4.10<tt>&nbsp;</tt><a name="(part._mpairs)"></a>Mutable Pairs and Lists</h4><p>A <a name="(tech._mutable._pair)"></a><span style="font-style: italic">mutable pair</span> is like a pair created by <span class="RktSym"><a href="pairs.html#%28def._%28%28quote._~23~25kernel%29._cons%29%29" class="RktValLink" data-pltdoc="x">cons</a></span>, but
it supports <span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._set-mcar%21%29%29" class="RktValLink" data-pltdoc="x">set-mcar!</a></span> and <span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._set-mcdr%21%29%29" class="RktValLink" data-pltdoc="x">set-mcdr!</a></span> mutation
operations to change the parts of the mutable pair (like traditional Lisp and
Scheme pairs).</p><p>A <a name="(tech._mutable._list)"></a><span style="font-style: italic">mutable list</span> is analogous to a list created with pairs, but
instead created with <a href="#%28tech._mutable._pair%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable pairs</span></a>.</p><p>A <a href="#%28tech._mutable._pair%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable pair</span></a> is not a <a href="pairs.html#%28tech._pair%29" class="techoutside" data-pltdoc="x"><span class="techinside">pair</span></a>; they are completely
separate datatypes. Similarly, a <a href="#%28tech._mutable._list%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable list</span></a> is not a
<a href="pairs.html#%28tech._list%29" class="techoutside" data-pltdoc="x"><span class="techinside">list</span></a>, except that the empty list is also the empty mutable
list. Instead of programming with mutable pairs and mutable lists,
data structures such as pairs, lists, and hash tables are practically
always better choices.</p><p>A <a href="#%28tech._mutable._list%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable list</span></a> can be used as a single-valued sequence (see
<a href="sequences.html" data-pltdoc="x">Sequences</a>). The elements of the <a href="#%28tech._mutable._list%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable list</span></a> serve as elements
of the sequence. See also <span class="RktSym"><a href="sequences.html#%28def._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._in-mlist%29%29" class="RktValLink" data-pltdoc="x">in-mlist</a></span>.</p><h5 x-source-module="(lib &quot;scribblings/reference/reference.scrbl&quot;)" x-source-pkg="racket-doc" x-part-tag="&quot;Mutable_Pair_Constructors_and_Selectors&quot;">4.10.1<tt>&nbsp;</tt><a name="(part._.Mutable_.Pair_.Constructors_and_.Selectors)"></a>Mutable Pair Constructors and Selectors</h5><p><div class="SIntrapara"><blockquote class="SVInsetFlow"><table cellspacing="0" cellpadding="0" class="boxed RBoxed"><tr><td><blockquote class="SubFlow"><div class="RBackgroundLabel SIEHidden"><div class="RBackgroundLabelInner"><p>procedure</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((quote._~23~25kernel)._mpair~3f))"></a><span title="Provided from: racket/base, racket | Package: base"><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._mpair~3f%29%29" class="RktValDef RktValLink" data-pltdoc="x">mpair?</a></span></span><span class="hspace">&nbsp;</span><span class="RktVar">v</span><span class="RktPn">)</span><span class="hspace">&nbsp;</span>&rarr;<span class="hspace">&nbsp;</span><span class="RktSym"><a href="booleans.html#%28def._%28%28quote._~23~25kernel%29._boolean~3f%29%29" class="RktValLink" data-pltdoc="x">boolean?</a></span></p></blockquote></td></tr><tr><td><span class="hspace">&nbsp;&nbsp;</span><span class="RktVar">v</span><span class="hspace">&nbsp;</span>:<span class="hspace">&nbsp;</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fprivate%2Fmisc..rkt%29._any%2Fc%29%29" class="RktValLink" data-pltdoc="x">any/c</a></span></td></tr></table></blockquote></div><div class="SIntrapara">Returns <span class="RktVal">#t</span> if <span class="RktVar">v</span> is
a <a href="#%28tech._mutable._pair%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable pair</span></a>, <span class="RktVal">#f</span> otherwise.</div></p><p><div class="SIntrapara"><blockquote class="SVInsetFlow"><table cellspacing="0" cellpadding="0" class="boxed RBoxed"><tr><td><blockquote class="SubFlow"><div class="RBackgroundLabel SIEHidden"><div class="RBackgroundLabelInner"><p>procedure</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((quote._~23~25kernel)._mcons))"></a><span title="Provided from: racket/base, racket | Package: base"><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._mcons%29%29" class="RktValDef RktValLink" data-pltdoc="x">mcons</a></span></span><span class="hspace">&nbsp;</span><span class="RktVar">a</span><span class="hspace">&nbsp;</span><span class="RktVar">d</span><span class="RktPn">)</span><span class="hspace">&nbsp;</span>&rarr;<span class="hspace">&nbsp;</span><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._mpair~3f%29%29" class="RktValLink" data-pltdoc="x">mpair?</a></span></p></blockquote></td></tr><tr><td><span class="hspace">&nbsp;&nbsp;</span><span class="RktVar">a</span><span class="hspace">&nbsp;</span>:<span class="hspace">&nbsp;</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fprivate%2Fmisc..rkt%29._any%2Fc%29%29" class="RktValLink" data-pltdoc="x">any/c</a></span></td></tr><tr><td><span class="hspace">&nbsp;&nbsp;</span><span class="RktVar">d</span><span class="hspace">&nbsp;</span>:<span class="hspace">&nbsp;</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fprivate%2Fmisc..rkt%29._any%2Fc%29%29" class="RktValLink" data-pltdoc="x">any/c</a></span></td></tr></table></blockquote></div><div class="SIntrapara">Returns a newly allocated
<a href="#%28tech._mutable._pair%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable pair</span></a> whose first
element is <span class="RktVar">a</span> and second element is <span class="RktVar">d</span>.</div></p><p><div class="SIntrapara"><blockquote class="SVInsetFlow"><table cellspacing="0" cellpadding="0" class="boxed RBoxed"><tr><td><blockquote class="SubFlow"><div class="RBackgroundLabel SIEHidden"><div class="RBackgroundLabelInner"><p>procedure</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((quote._~23~25kernel)._mcar))"></a><span title="Provided from: racket/base, racket | Package: base"><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._mcar%29%29" class="RktValDef RktValLink" data-pltdoc="x">mcar</a></span></span><span class="hspace">&nbsp;</span><span class="RktVar">p</span><span class="RktPn">)</span><span class="hspace">&nbsp;</span>&rarr;<span class="hspace">&nbsp;</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fprivate%2Fmisc..rkt%29._any%2Fc%29%29" class="RktValLink" data-pltdoc="x">any/c</a></span></p></blockquote></td></tr><tr><td><span class="hspace">&nbsp;&nbsp;</span><span class="RktVar">p</span><span class="hspace">&nbsp;</span>:<span class="hspace">&nbsp;</span><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._mpair~3f%29%29" class="RktValLink" data-pltdoc="x">mpair?</a></span></td></tr></table></blockquote></div><div class="SIntrapara">Returns the first element of the
<a href="#%28tech._mutable._pair%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable pair</span></a> <span class="RktVar">p</span>.</div></p><p><div class="SIntrapara"><blockquote class="SVInsetFlow"><table cellspacing="0" cellpadding="0" class="boxed RBoxed"><tr><td><blockquote class="SubFlow"><div class="RBackgroundLabel SIEHidden"><div class="RBackgroundLabelInner"><p>procedure</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((quote._~23~25kernel)._mcdr))"></a><span title="Provided from: racket/base, racket | Package: base"><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._mcdr%29%29" class="RktValDef RktValLink" data-pltdoc="x">mcdr</a></span></span><span class="hspace">&nbsp;</span><span class="RktVar">p</span><span class="RktPn">)</span><span class="hspace">&nbsp;</span>&rarr;<span class="hspace">&nbsp;</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fprivate%2Fmisc..rkt%29._any%2Fc%29%29" class="RktValLink" data-pltdoc="x">any/c</a></span></p></blockquote></td></tr><tr><td><span class="hspace">&nbsp;&nbsp;</span><span class="RktVar">p</span><span class="hspace">&nbsp;</span>:<span class="hspace">&nbsp;</span><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._mpair~3f%29%29" class="RktValLink" data-pltdoc="x">mpair?</a></span></td></tr></table></blockquote></div><div class="SIntrapara">Returns the second element of the
<a href="#%28tech._mutable._pair%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable pair</span></a> <span class="RktVar">p</span>.</div></p><p><div class="SIntrapara"><blockquote class="SVInsetFlow"><table cellspacing="0" cellpadding="0" class="boxed RBoxed"><tr><td><blockquote class="SubFlow"><div class="RBackgroundLabel SIEHidden"><div class="RBackgroundLabelInner"><p>procedure</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((quote._~23~25kernel)._set-mcar!))"></a><span title="Provided from: racket/base, racket | Package: base"><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._set-mcar%21%29%29" class="RktValDef RktValLink" data-pltdoc="x">set-mcar!</a></span></span><span class="hspace">&nbsp;</span><span class="RktVar">p</span><span class="hspace">&nbsp;</span><span class="RktVar">v</span><span class="RktPn">)</span><span class="hspace">&nbsp;</span>&rarr;<span class="hspace">&nbsp;</span><span class="RktSym"><a href="void.html#%28def._%28%28quote._~23~25kernel%29._void~3f%29%29" class="RktValLink" data-pltdoc="x">void?</a></span></p></blockquote></td></tr><tr><td><span class="hspace">&nbsp;&nbsp;</span><span class="RktVar">p</span><span class="hspace">&nbsp;</span>:<span class="hspace">&nbsp;</span><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._mpair~3f%29%29" class="RktValLink" data-pltdoc="x">mpair?</a></span></td></tr><tr><td><span class="hspace">&nbsp;&nbsp;</span><span class="RktVar">v</span><span class="hspace">&nbsp;</span>:<span class="hspace">&nbsp;</span><span class="RktSym">any/v</span></td></tr></table></blockquote></div><div class="SIntrapara">Changes the <a href="#%28tech._mutable._pair%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable pair</span></a> <span class="RktVar">p</span> so that its first element is
<span class="RktVar">v</span>.</div></p><p><div class="SIntrapara"><blockquote class="SVInsetFlow"><table cellspacing="0" cellpadding="0" class="boxed RBoxed"><tr><td><blockquote class="SubFlow"><div class="RBackgroundLabel SIEHidden"><div class="RBackgroundLabelInner"><p>procedure</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((quote._~23~25kernel)._set-mcdr!))"></a><span title="Provided from: racket/base, racket | Package: base"><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._set-mcdr%21%29%29" class="RktValDef RktValLink" data-pltdoc="x">set-mcdr!</a></span></span><span class="hspace">&nbsp;</span><span class="RktVar">p</span><span class="hspace">&nbsp;</span><span class="RktVar">v</span><span class="RktPn">)</span><span class="hspace">&nbsp;</span>&rarr;<span class="hspace">&nbsp;</span><span class="RktSym"><a href="void.html#%28def._%28%28quote._~23~25kernel%29._void~3f%29%29" class="RktValLink" data-pltdoc="x">void?</a></span></p></blockquote></td></tr><tr><td><span class="hspace">&nbsp;&nbsp;</span><span class="RktVar">p</span><span class="hspace">&nbsp;</span>:<span class="hspace">&nbsp;</span><span class="RktSym"><a href="#%28def._%28%28quote._~23~25kernel%29._mpair~3f%29%29" class="RktValLink" data-pltdoc="x">mpair?</a></span></td></tr><tr><td><span class="hspace">&nbsp;&nbsp;</span><span class="RktVar">v</span><span class="hspace">&nbsp;</span>:<span class="hspace">&nbsp;</span><span class="RktSym">any/v</span></td></tr></table></blockquote></div><div class="SIntrapara">Changes the <a href="#%28tech._mutable._pair%29" class="techoutside" data-pltdoc="x"><span class="techinside">mutable pair</span></a> <span class="RktVar">p</span> so that its second element is
<span class="RktVar">v</span>.</div></p><div class="navsetbottom"><span class="navleft"><form class="searchform"><input class="searchbox" style="color: #888;" type="text" value="...search manuals..." title="Enter a search string to search the manuals" onkeypress="return DoSearchKey(event, this, &quot;6.7&quot;, &quot;../&quot;);" onfocus="this.style.color=&quot;black&quot;; this.style.textAlign=&quot;left&quot;; if (this.value == &quot;...search manuals...&quot;) this.value=&quot;&quot;;" onblur="if (this.value.match(/^ *$/)) { this.style.color=&quot;#888&quot;; this.style.textAlign=&quot;center&quot;; this.value=&quot;...search manuals...&quot;; }"/></form>&nbsp;&nbsp;<a href="../index.html" title="up to the documentation top" data-pltdoc="x" onclick="return GotoPLTRoot(&quot;6.7&quot;);">top</a></span><span class="navright">&nbsp;&nbsp;<a href="pairs.html" title="backward to &quot;4.9 Pairs and Lists&quot;" data-pltdoc="x">&larr; prev</a>&nbsp;&nbsp;<a href="data.html" title="up to &quot;4 Datatypes&quot;" data-pltdoc="x">up</a>&nbsp;&nbsp;<a href="vectors.html" title="forward to &quot;4.11 Vectors&quot;" data-pltdoc="x">next &rarr;</a></span>&nbsp;</div></div></div><div id="contextindicator">&nbsp;</div></body></html>