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<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"/><meta name="viewport" content="width=device-width, initial-scale=0.8"/><title>3.20 Quasiquoting: quasiquote, unquote, and unquote-splicing</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="icons.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,"tocview_0");">►</a></td><td></td><td><a href="index.html" class="tocviewlink" data-pltdoc="x">The Racket Reference</a></td></tr></table></div><div class="tocviewsublisttop" style="display: none;" id="tocview_0"><table cellspacing="0" cellpadding="0"><tr><td align="right">1 </td><td><a href="model.html" class="tocviewlink" data-pltdoc="x">Language Model</a></td></tr><tr><td align="right">2 </td><td><a href="notation.html" class="tocviewlink" data-pltdoc="x">Notation for Documentation</a></td></tr><tr><td align="right">3 </td><td><a href="syntax.html" class="tocviewselflink" data-pltdoc="x">Syntactic Forms</a></td></tr><tr><td align="right">4 </td><td><a href="data.html" class="tocviewlink" data-pltdoc="x">Datatypes</a></td></tr><tr><td align="right">5 </td><td><a href="structures.html" class="tocviewlink" data-pltdoc="x">Structures</a></td></tr><tr><td align="right">6 </td><td><a href="mzlib_class.html" class="tocviewlink" data-pltdoc="x">Classes and Objects</a></td></tr><tr><td align="right">7 </td><td><a href="mzlib_unit.html" class="tocviewlink" data-pltdoc="x">Units</a></td></tr><tr><td align="right">8 </td><td><a href="contracts.html" class="tocviewlink" data-pltdoc="x">Contracts</a></td></tr><tr><td align="right">9 </td><td><a href="match.html" class="tocviewlink" data-pltdoc="x">Pattern Matching</a></td></tr><tr><td align="right">10 </td><td><a href="control.html" class="tocviewlink" data-pltdoc="x">Control Flow</a></td></tr><tr><td align="right">11 </td><td><a href="concurrency.html" class="tocviewlink" data-pltdoc="x">Concurrency and Parallelism</a></td></tr><tr><td align="right">12 </td><td><a href="Macros.html" class="tocviewlink" data-pltdoc="x">Macros</a></td></tr><tr><td align="right">13 </td><td><a href="input-and-output.html" class="tocviewlink" data-pltdoc="x">Input and Output</a></td></tr><tr><td align="right">14 </td><td><a href="security.html" class="tocviewlink" data-pltdoc="x">Reflection and Security</a></td></tr><tr><td align="right">15 </td><td><a href="os.html" class="tocviewlink" data-pltdoc="x">Operating System</a></td></tr><tr><td align="right">16 </td><td><a href="memory.html" class="tocviewlink" data-pltdoc="x">Memory Management</a></td></tr><tr><td align="right">17 </td><td><a href="unsafe.html" class="tocviewlink" data
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<span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span><span class="stt"> </span><span class="RktVar">expr</span><span class="RktPn">)</span> or <span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span><span class="stt"> </span><span class="RktVar">expr</span><span class="RktPn">)</span>. An
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<span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span><span class="stt"> </span><span class="RktVar">expr</span><span class="RktPn">)</span> form escapes from the quote, however,
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and the result of the <span class="RktVar">expr</span> takes the place of the
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<span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span><span class="stt"> </span><span class="RktVar">expr</span><span class="RktPn">)</span> form in the <span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span> result. An
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<span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span><span class="stt"> </span><span class="RktVar">expr</span><span class="RktPn">)</span> similarly escapes, but the
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<span class="RktVar">expr</span> produces a list whose elements are spliced as
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multiple values place of the <span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span><span class="stt"> </span><span class="RktVar">expr</span><span class="RktPn">)</span>.</div></p><p>An <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span> or <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span> form is recognized in any
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of the following escaping positions within <span class="RktVar">datum</span>: in a pair,
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in a vector, in a box, in a <a href="structures.html#%28tech._prefab%29" class="techoutside" data-pltdoc="x"><span class="techinside">prefab</span></a> structure field after the
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name position, and in hash table value position (but not in a hash
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table key position). Such escaping positions can be nested to an
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arbitrary depth.</p><p>An <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span> form must appear as the <span class="RktSym"><a href="pairs.html#%28def._%28%28quote._~23~25kernel%29._car%29%29" class="RktValLink" data-pltdoc="x">car</a></span> of a
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quoted pair, as an element of a quoted vector, or as an element of a
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quoted <a href="structures.html#%28tech._prefab%29" class="techoutside" data-pltdoc="x"><span class="techinside">prefab</span></a> structure. In the case of a pair, if the
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<span class="RktSym"><a href="pairs.html#%28def._%28%28quote._~23~25kernel%29._cdr%29%29" class="RktValLink" data-pltdoc="x">cdr</a></span> of the relevant quoted pair is empty, then <span class="RktVar">expr</span>
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need not produce a list, and its result is used directly in place of
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the quoted pair (in the same way that <span class="RktSym"><a href="pairs.html#%28def._%28%28quote._~23~25kernel%29._append%29%29" class="RktValLink" data-pltdoc="x">append</a></span> accepts a
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non-list final argument).</p><p>If <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span> or <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span> appears within
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<span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span> in an escaping position but in a way other than as
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<span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span><span class="stt"> </span><span class="RktVar">expr</span><span class="RktPn">)</span> or <span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span><span class="stt"> </span><span class="RktVar">expr</span><span class="RktPn">)</span>, a syntax error is reported.</p><p><div class="SIntrapara">Examples:</div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktVal">0</span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'(0 1 2)</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktVal">0</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="generic-numbers.html#%28def._%28%28quote._~23~25kernel%29._%2B%29%29" class="RktValLink" data-pltdoc="x">+</a></span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="RktPn">)</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktVal">4</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'(0 3 4)</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktVal">0</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="pairs.html#%28def._%28%28quote._~23~25kernel%29._list%29%29" class="RktValLink" data-pltdoc="x">list</a></span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="RktPn">)</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktVal">4</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'(0 1 2 4)</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktVal">0</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kerne
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form is typically abbreviated with <span class="RktInBG"><span class="hspace"></span><span class="RktIn">`</span><span class="hspace"></span></span>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">,</span><span class="hspace"></span></span>, or
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<span class="RktInBG"><span class="hspace"></span><span class="RktIn">,@</span><span class="hspace"></span></span>, respectively. See also <a href="reader.html#%28part._parse-quote%29" data-pltdoc="x">Reading Quotes</a>.</p><p><div class="SIntrapara">Examples:</div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktVal">`</span><span class="RktVal">(</span><span class="RktVal">0</span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="RktVal">)</span></td></tr><tr><td><p><span class="RktRes">'(0 1 2)</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktVal">`</span><span class="RktVal">(</span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktRdr">,</span><span class="RktPn">(</span><span class="RktSym"><a href="generic-numbers.html#%28def._%28%28quote._~23~25kernel%29._%2B%29%29" class="RktValLink" data-pltdoc="x">+</a></span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktVal">4</span><span class="RktVal">)</span></td></tr><tr><td><p><span class="RktRes">'(1 3 4)</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktVal">`</span><span class="RktVal">#s</span><span class="RktVal">(</span><span class="RktVal">stuff</span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktRdr">,</span><span class="RktPn">(</span><span class="RktSym"><a href="generic-numbers.html#%28def._%28%28quote._~23~25kernel%29._%2B%29%29" class="RktValLink" data-pltdoc="x">+</a></span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktVal">4</span><span class="RktVal">)</span></td></tr><tr><td><p><span class="RktRes">'#s(stuff 1 3 4)</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktVal">`</span><span class="RktVal">#hash</span><span class="RktVal">(</span><span class="RktVal">(</span><span class="RktVal">"a"</span><span class="hspace"> </span><span class="RktVal">. </span><span class="RktRdr">,</span><span class="RktPn">(</span><span class="RktSym"><a href="generic-numbers.html#%28def._%28%28quote._~23~25kernel%29._%2B%29%29" class="RktValLink" data-pltdoc="x">+</a></span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="RktPn">)</span><span class="RktVal">)</span><span class="RktVal">)</span></td></tr><tr><td><p><span class="RktRes">'#hash(("a" . 3))</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktVal">`</span><span class="RktVal">#hash</span><span class="RktVal">(</span><span class="RktVal">(</span><span class="RktVal">,</span><span class="RktVal">(</span><span class="RktVal">+</span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="RktVal">)</span><span class="hspace"> </span><span class="RktVal">. </span><span class="RktVal">"a"</span><span class="RktVal">)</span><span class="RktVal">)</span></td></tr><tr><td><p><span class="RktRes">'#hash((,(+ 1 2) . "a"))</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktVal">`</span><span class="RktVal">(</span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktRdr">,@</span><span class="RktPn">(</span><span class="RktSym"><a href="pairs.html#%28def._%28%28quote._~23~25kernel%29._list%29%29" class="RktValLink" data-pltdoc="x">list</a></span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="RktPn">)</span><spa
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increments the level of quasiquotation: within the <span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span>
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form, each <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span> or <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span> is preserved,
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but a further nested <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span> or <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span>
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escapes. Multiple nestings of <span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span> require multiple
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nestings of <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span> or <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span> to escape.</p><p><div class="SIntrapara">Examples:</div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktVal">`</span><span class="RktVal">(</span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">`</span><span class="RktVal">,</span><span class="RktVal">(</span><span class="RktVal">+</span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktRdr">,</span><span class="RktPn">(</span><span class="RktSym"><a href="generic-numbers.html#%28def._%28%28quote._~23~25kernel%29._%2B%29%29" class="RktValLink" data-pltdoc="x">+</a></span><span class="hspace"> </span><span class="RktVal">2</span><span class="hspace"> </span><span class="RktVal">3</span><span class="RktPn">)</span><span class="RktVal">)</span><span class="hspace"> </span><span class="RktVal">4</span><span class="RktVal">)</span></td></tr><tr><td><p><span class="RktRes">'(1 `,(+ 1 5) 4)</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktVal">`</span><span class="RktVal">(</span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">`</span><span class="RktVal">`</span><span class="RktVal">`</span><span class="RktVal">,</span><span class="RktVal">,@</span><span class="RktVal">,</span><span class="RktRdr">,@</span><span class="RktPn">(</span><span class="RktSym"><a href="pairs.html#%28def._%28%28quote._~23~25kernel%29._list%29%29" class="RktValLink" data-pltdoc="x">list</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="generic-numbers.html#%28def._%28%28quote._~23~25kernel%29._%2B%29%29" class="RktValLink" data-pltdoc="x">+</a></span><span class="hspace"> </span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="RktPn">)</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktVal">4</span><span class="RktVal">)</span></td></tr><tr><td><p><span class="RktRes">'(1 ```,,@,3 4)</span></p></td></tr></table></blockquote></div></p><p>The <span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span> form allocates only as many fresh cons cells,
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vectors, and boxes as are needed without analyzing <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span>
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and <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span> expressions. For example, in</p><blockquote class="SCodeFlow"><p><span class="RktVal">`</span><span class="RktVal">(</span><span class="RktRdr">,</span><span class="RktVal">1</span><span class="hspace"> </span><span class="RktVal">2</span><span class="hspace"> </span><span class="RktVal">3</span><span class="RktVal">)</span></p></blockquote><p>a single tail <span class="RktVal">'</span><span class="RktVal">(</span><span class="RktVal">2</span><span class="stt"> </span><span class="RktVal">3</span><span class="RktVal">)</span> is used for every evaluation of the
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<span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span> expression. When allocating fresh data,
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the <span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span> form allocates mutable vectors, mutable boxes
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and immutable hashes.</p><p><div class="SIntrapara">Examples:</div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="booleans.html#%28def._%28%28quote._~23~25kernel%29._immutable~3f%29%29" class="RktValLink" data-pltdoc="x">immutable?</a></span><span class="hspace"> </span><span class="RktVal">`</span><span class="RktVal">#</span><span class="RktVal">(</span><span class="RktRdr">,</span><span class="RktVal">0</span><span class="RktVal">)</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#f</span></p></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="booleans.html#%28def._%28%28quote._~23~25kernel%29._immutable~3f%29%29" class="RktValLink" data-pltdoc="x">immutable?</a></span><span class="hspace"> </span><span class="RktVal">`</span><span class="RktVal">#hash</span><span class="RktVal">(</span><span class="RktVal">(</span><span class="RktVal">a</span><span class="hspace"> </span><span class="RktVal">. </span><span class="RktRdr">,</span><span class="RktVal">0</span><span class="RktVal">)</span><span class="RktVal">)</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#t</span></p></td></tr></table></blockquote></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>syntax</p></div></div><p class="RForeground"><a name="(form._((quote._~23~25kernel)._unquote))"></a><span title="Provided from: racket/base, racket | Package: base"><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxDef RktStxLink" data-pltdoc="x">unquote</a></span></span></p></blockquote></td></tr></table></blockquote></div><div class="SIntrapara">See <span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span>, where <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span> is recognized as an
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escape. An <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote%29%29" class="RktStxLink" data-pltdoc="x">unquote</a></span> form as an expression is a syntax error.</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>syntax</p></div></div><p class="RForeground"><a name="(form._((quote._~23~25kernel)._unquote-splicing))"></a><span title="Provided from: racket/base, racket | Package: base"><span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxDef RktStxLink" data-pltdoc="x">unquote-splicing</a></span></span></p></blockquote></td></tr></table></blockquote></div><div class="SIntrapara">See <span class="RktSym"><a href="quasiquote.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._quasiquote%29%29" class="RktStxLink" data-pltdoc="x">quasiquote</a></span>, where <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span> is recognized as an
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escape. An <span class="RktSym"><a href="quasiquote.html#%28form._%28%28quote._~23~25kernel%29._unquote-splicing%29%29" class="RktStxLink" data-pltdoc="x">unquote-splicing</a></span> form as an expression is a syntax error.</div></p><div class="navsetbottom"><span class="navleft"><form class="searchform"><input class="searchbox" id="searchbox" type="text" tabindex="1" placeholder="...search manuals..." title="Enter a search string to search the manuals" onkeypress="return DoSearchKey(event, this, "8.6", "../");"/></form> <a href="https://docs.racket-lang.org/index.html" title="up to the documentation top" data-pltdoc="x" onclick="return GotoPLTRoot("8.6");">top</a><span class="tocsettoggle"> <a href="javascript:void(0);" title="show/hide table of contents" onclick="TocsetToggle();">contents</a></span></span><span class="navright"> <a href="wcm.html" title="backward to "3.19 Continuation Marks: with-continuation-mark"" data-pltdoc="x">← prev</a> <a href="syntax.html" title="up to "3 Syntactic Forms"" data-pltdoc="x">up</a> <a href="Syntax_Quoting__quote-syntax.html" title="forward to "3.21 Syntax Quoting: quote-syntax"" data-pltdoc="x">next →</a></span> </div></div></div><div id="contextindicator"> </div></body></html>
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