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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>12.12 Syntax Utilities</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,"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="tocviewlink" 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="tocviewselflink" 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-pltdoc="x">Unsafe Operations</a></td></tr><tr><td align="right">18 </td><td><a href="running.html" class=
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for the lexical context, <span class="RktVar">src</span> for the source location, and
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<span class="RktVar">props</span> for the properties. An argument supplied with
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<span class="RktPn">#:cert</span> is ignored. (See <span class="RktSym"><a href="stxops.html#%28def._%28%28quote._~23~25kernel%29._datum-~3esyntax%29%29" class="RktValLink" data-pltdoc="x">datum->syntax</a></span>.)</div></p><p>The format string must use only <span class="RktInBG"><span class="hspace"></span><span class="RktIn">~a</span><span class="hspace"></span></span> placeholders. Identifiers
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in the argument list are automatically converted to symbols.</p><p><div class="SIntrapara">Examples:</div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define-syntax%29%29" class="RktStxLink" data-pltdoc="x">define-syntax</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">make-pred</span><span class="hspace"> </span><span class="RktSym">stx</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._syntax-case%29%29" class="RktStxLink" data-pltdoc="x">syntax-case</a></span><span class="hspace"> </span><span class="RktSym">stx</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">[</span><span class="RktPn">(</span><span class="RktSym">make-pred</span><span class="hspace"> </span><span class="RktSym">name</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._format-id%29%29" class="RktValLink" data-pltdoc="x">format-id</a></span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">name</span><span class="hspace"> </span><span class="RktVal">"~a?"</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="stxops.html#%28def._%28%28quote._~23~25kernel%29._syntax-e%29%29" class="RktValLink" data-pltdoc="x">syntax-e</a></span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">name</span><span class="RktPn">)</span><span class="RktPn">)</span><span class="RktPn">]</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">make-pred</span><span class="hspace"> </span><span class="RktSym">pair</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#<procedure:pair?></span></p></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">make-pred</span><span class="hspace"> </span><span class="RktSym">none-such</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktErr">none-such?: undefined;</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">cannot reference an identifier before its definition</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">in module: top-level</span></p></td></tr><tr><td><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define-syntax%29%29" class="RktStxLink" data-pltdoc="x">define-syntax</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">better-make-pred</span><span class="hspace"> </span><span class="RktSym">stx</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._syntax-case%29%29" class="RktStxLink" data-pltdoc="x">syn
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the second error but not of the first.)</p><p>If <span class="RktVar">subs?</span> is <span class="RktVal">#t</span>, then a <span class="RktVal">'</span><span class="RktVal">sub-range-binders</span>
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syntax property is added to the result that records the position of
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each identifier in the <span class="RktVar">v</span>s. The <span class="RktSym">subs-intro</span> procedure
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is applied to each identifier, and its result is included in the
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sub-range binder record. This property value overrides a
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<span class="RktVal">'</span><span class="RktVal">sub-range-binders</span> property copied from <span class="RktVar">props</span>.</p><p><div class="SIntrapara">Example:</div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="stxprops.html#%28def._%28%28quote._~23~25kernel%29._syntax-property%29%29" class="RktValLink" data-pltdoc="x">syntax-property</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._format-id%29%29" class="RktValLink" data-pltdoc="x">format-id</a></span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">here</span><span class="hspace"> </span><span class="RktVal">"~a/~a-~a"</span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">point</span><span class="hspace"> </span><span class="RktVal">2</span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">y</span><span class="hspace"> </span><span class="RktPn">#:subs?</span><span class="hspace"> </span><span class="RktVal">#t</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">sub-range-binders</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><table cellspacing="0" cellpadding="0"><tr><td><p><span class="RktRes">'(#(#<syntax point/2-y> 8 1 0.5 0.5 #<syntax:eval:8:0 y> 0 1 0.5 0.5)</span></p></td></tr><tr><td><p><span class="RktRes"></span><span class="hspace"> </span><span class="RktRes">#(#<syntax point/2-y> 0 5 0.5 0.5 #<syntax:eval:8:0 point> 0 5 0.5 0.5))</span></p></td></tr></table></td></tr></table></blockquote></div></p><p class="SHistory">Changed in version 7.4.0.5 of package <span class="stt">base</span>: Added the <span class="RktPn">#:subs?</span> and
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<span class="RktPn">#:subs-intro</span> arguments.</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._((lib._racket/syntax..rkt)._format-symbol))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._format-symbol%29%29" class="RktValDef RktValLink" data-pltdoc="x">format-symbol</a></span></span><span class="hspace"> </span><span class="RktVar">fmt</span><span class="hspace"> </span><span class="RktVar">v</span><span class="hspace"> </span><span class="RktMeta">...</span><span class="RktPn">)</span><span class="hspace"> </span>→<span class="hspace"> </span><span class="RktSym"><a href="symbols.html#%28def._%28%28quote._~23~25kernel%29._symbol~3f%29%29" class="RktValLink" data-pltdoc="x">symbol?</a></span></p></blockquote></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">fmt</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="strings.html#%28def._%28%28quote._~23~25kernel%29._string~3f%29%29" class="RktValLink" data-pltdoc="x">string?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">v</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fbase..rkt%29._or%2Fc%29%29" class="RktValLink" data-pltdoc="x">or/c</a></span><span class="hspace"> </span><span class="RktSym"><a href="strings.html#%28def._%28%28quote._~23~25kernel%29._string~3f%29%29" class="RktValLink" data-pltdoc="x">string?</a></span><span class="hspace"> </span><span class="RktSym"><a href="symbols.html#%28def._%28%28quote._~23~25kernel%29._symbol~3f%29%29" class="RktValLink" data-pltdoc="x">symbol?</a></span><span class="hspace"> </span><span class="RktSym"><a href="stxops.html#%28def._%28%28lib._racket%2Fprivate%2Fstx..rkt%29._identifier~3f%29%29" class="RktValLink" data-pltdoc="x">identifier?</a></span><span class="hspace"> </span><span class="RktSym"><a href="keywords.html#%28def._%28%28quote._~23~25kernel%29._keyword~3f%29%29" class="RktValLink" data-pltdoc="x">keyword?</a></span><span class="hspace"> </span><span class="RktSym"><a href="characters.html#%28def._%28%28quote._~23~25kernel%29._char~3f%29%29" class="RktValLink" data-pltdoc="x">char?</a></span><span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._number~3f%29%29" class="RktValLink" data-pltdoc="x">number?</a></span><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">Like <span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._format%29%29" class="RktValLink" data-pltdoc="x">format</a></span>, but produces a symbol. The format string must
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use only <span class="RktInBG"><span class="hspace"></span><span class="RktIn">~a</span><span class="hspace"></span></span> placeholders. Identifiers in the argument list
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are automatically converted to symbols.</div></p><p><div class="SIntrapara">Example:</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="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._format-symbol%29%29" class="RktValLink" data-pltdoc="x">format-symbol</a></span><span class="hspace"> </span><span class="RktVal">"make-~a"</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">triple</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">'make-triple</span></p></td></tr></table></blockquote></div></p><h5 x-source-module="(lib "scribblings/reference/reference.scrbl")" x-source-pkg="racket-doc" x-part-tag=""Pattern_variables"">12.12.2<tt> </tt><a name="(part._.Pattern_variables)"></a>Pattern variables</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>syntax</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(form._((lib._racket/syntax..rkt)._define/with-syntax))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28form._%28%28lib._racket%2Fsyntax..rkt%29._define%2Fwith-syntax%29%29" class="RktStxDef RktStxLink" data-pltdoc="x">define/with-syntax</a></span></span><span class="hspace"> </span><span class="RktVar">pattern</span><span class="hspace"> </span><span class="RktVar">stx-expr</span><span class="RktPn">)</span></p></blockquote></td></tr><tr><td><span class="stt"> </span></td></tr><tr><td><table cellspacing="0" cellpadding="0" class="argcontract"><tr><td><span class="hspace"> </span></td><td><span class="RktVar">stx-expr</span></td><td><span class="hspace"> </span></td><td>:</td><td><span class="hspace"> </span></td><td><span class="RktSym"><a href="stxops.html#%28def._%28%28quote._~23~25kernel%29._syntax~3f%29%29" class="RktValLink" data-pltdoc="x">syntax?</a></span></td></tr></table></td></tr></table></blockquote></div><div class="SIntrapara">Definition form of <span class="RktSym"><a href="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._with-syntax%29%29" class="RktStxLink" data-pltdoc="x">with-syntax</a></span>. That is, it matches the
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syntax object result of <span class="RktVar">stx-expr</span> against <span class="RktVar">pattern</span> and
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creates pattern variable definitions for the pattern variables of
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<span class="RktVar">pattern</span>.</div></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="syntax-util.html#%28form._%28%28lib._racket%2Fsyntax..rkt%29._define%2Fwith-syntax%29%29" class="RktStxLink" data-pltdoc="x">define/with-syntax</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">px</span><span class="hspace"> </span><span class="RktMeta"><a href="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._......%29%29" class="RktStxLink" data-pltdoc="x">...</a></span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktPn">(</span><span class="RktSym">a</span><span class="hspace"> </span><span class="RktSym">b</span><span class="hspace"> </span><span class="RktSym">c</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="syntax-util.html#%28form._%28%28lib._racket%2Fsyntax..rkt%29._define%2Fwith-syntax%29%29" class="RktStxLink" data-pltdoc="x">define/with-syntax</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">tmp</span><span class="hspace"> </span><span class="RktMeta"><a href="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._......%29%29" class="RktStxLink" data-pltdoc="x">...</a></span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="stxops.html#%28def._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._generate-temporaries%29%29" class="RktValLink" data-pltdoc="x">generate-temporaries</a></span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktPn">(</span><span class="RktSym">px</span><span class="hspace"> </span><span class="RktMeta"><a href="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._......%29%29" class="RktStxLink" data-pltdoc="x">...</a></span><span class="RktPn">)</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><span class="stt">> </span><span class="RktRdr">#'</span><span class="RktPn">(</span><span class="RktPn">[</span><span class="RktSym">tmp</span><span class="hspace"> </span><span class="RktSym">px</span><span class="RktPn">]</span><span class="hspace"> </span><span class="RktMeta"><a href="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._......%29%29" class="RktStxLink" data-pltdoc="x">...</a></span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#<syntax:eval:12:0 ((a9 a) (b10 b) (c11 c))></span></p></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="syntax-util.html#%28form._%28%28lib._racket%2Fsyntax..rkt%29._define%2Fwith-syntax%29%29" class="RktStxLink" data-pltdoc="x">define/with-syntax</a></span><span class="hspace"> </span><span class="RktSym">name</span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">Alice</span><span class="RktPn">)</span></td></tr><tr><td><span class="stt">> </span><span class="RktRdr">#'</span><span class="RktPn">(</span><span class="RktSym">hello</span><span class="hspace"> </span><span class="RktSym">name</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktRes">#<syntax:eval:14:0 (hello Alice)></span></p></td></tr></table></blockquote></div></p><h5 x-source-module="(lib "scribblings/reference/reference.scrbl")" x-source-pkg="racket-doc" x-part-tag=""Error_reporting"">12.12.3<tt> </tt><a name="(part._.Error_reporting)"></a>Error reporting</h5><p><div class="SIntrapara"><blockquote class="SVInsetFlow"><table cellspacing="0" cellpadding="0" class="boxed R
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determines the special form name that prefixes syntax errors created
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by <span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._wrong-syntax%29%29" class="RktValLink" data-pltdoc="x">wrong-syntax</a></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._((lib._racket/syntax..rkt)._wrong-syntax))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._wrong-syntax%29%29" class="RktValDef RktValLink" data-pltdoc="x">wrong-syntax</a></span></span><span class="hspace"> </span><span class="RktVar">stx</span><span class="hspace"> </span><span class="RktVar">format-string</span><span class="hspace"> </span><span class="RktVar">v</span><span class="hspace"> </span><span class="RktMeta">...</span><span class="RktPn">)</span><span class="hspace"> </span>→<span class="hspace"> </span><span class="RktSym"><a href="data-structure-contracts.html#%28form._%28%28lib._racket%2Fcontract%2Fprivate%2Fmisc..rkt%29._any%29%29" class="RktStxLink" data-pltdoc="x">any</a></span></p></blockquote></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">stx</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="stxops.html#%28def._%28%28quote._~23~25kernel%29._syntax~3f%29%29" class="RktValLink" data-pltdoc="x">syntax?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">format-string</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="strings.html#%28def._%28%28quote._~23~25kernel%29._string~3f%29%29" class="RktValLink" data-pltdoc="x">string?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">v</span><span class="hspace"> </span>:<span class="hspace"> </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">Raises a syntax error using the result of
|
||
|
|
<span class="RktPn">(</span><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._current-syntax-context%29%29" class="RktValLink" data-pltdoc="x">current-syntax-context</a></span><span class="RktPn">)</span> as the “major” syntax object and
|
||
|
|
the provided <span class="RktVar">stx</span> as the specific syntax object. (The latter,
|
||
|
|
<span class="RktVar">stx</span>, is usually the one highlighted by DrRacket.) The error
|
||
|
|
message is constructed using the format string and arguments, and it
|
||
|
|
is prefixed with the special form name as described under
|
||
|
|
<span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._current-syntax-context%29%29" class="RktValLink" data-pltdoc="x">current-syntax-context</a></span>.</div></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="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._wrong-syntax%29%29" class="RktValLink" data-pltdoc="x">wrong-syntax</a></span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">here</span><span class="hspace"> </span><span class="RktVal">"expected ~s"</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">there</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktErr">eval:15:0: ?: expected there</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">at: here</span></p></td></tr><tr><td><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="parameters.html#%28form._%28%28lib._racket%2Fprivate%2Fmore-scheme..rkt%29._parameterize%29%29" class="RktStxLink" data-pltdoc="x">parameterize</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">[</span><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._current-syntax-context%29%29" class="RktValLink" data-pltdoc="x">current-syntax-context</a></span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktPn">(</span><span class="RktSym">look</span><span class="hspace"> </span><span class="RktSym">over</span><span class="hspace"> </span><span class="RktSym">here</span><span class="RktPn">)</span><span class="RktPn">]</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._wrong-syntax%29%29" class="RktValLink" data-pltdoc="x">wrong-syntax</a></span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">here</span><span class="hspace"> </span><span class="RktVal">"expected ~s"</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">there</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><p><span class="RktErr">eval:16:0: look: expected there</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">at: here</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">in: (look over here)</span></p></td></tr></table></blockquote></div></p><p><div class="SIntrapara">A macro using <span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._wrong-syntax%29%29" class="RktValLink" data-pltdoc="x">wrong-syntax</a></span> might set the syntax context at the very
|
||
|
|
beginning of its transformation as follows:
|
||
|
|
</div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="RktPn">(</span><span class="RktSym"><a href="define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define-syntax%29%29" class="RktStxLink" data-pltdoc="x">define-syntax</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">my-macro</span><span class="hspace"> </span><span class="RktVar">stx</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="parameters.html#%28form._%28%28lib._racket%2Fprivate%2Fmore-scheme..rkt%29._parameterize%29%29" class="RktStxLink" data-pltdoc="x">parameterize</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">[</span><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._current-syntax-context%29%29" class="RktValLink" data-pltdoc="x">current-syntax-context</a></span><span class="hspace"> </span><span class="RktVar">stx</span><span class="RktPn">]</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._syntax-case%29%29" class="RktStxLink" data-pltdoc="x">syntax-case</a></span><span class="hspace"> </span><span class="RktVar">stx</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">__</span><span class="RktPn">)</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">Then any calls to <span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._wrong-syntax%29%29" class="RktValLink" data-pltdoc="x">wrong-syntax</a></span> during the macro’s
|
||
|
|
transformation will refer to <span class="RktSym">my-macro</span> (more precisely, the name that
|
||
|
|
referred to <span class="RktSym">my-macro</span> where the macro was used, which may be
|
||
|
|
different due to renaming, prefixing, etc).</div></p><h5 x-source-module="(lib "scribblings/reference/reference.scrbl")" x-source-pkg="racket-doc" x-part-tag=""Recording_disappeared_uses"">12.12.4<tt> </tt><a name="(part._.Recording_disappeared_uses)"></a>Recording disappeared uses</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>parameter</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/syntax..rkt)._current-recorded-disappeared-uses))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._current-recorded-disappeared-uses%29%29" class="RktValDef RktValLink" data-pltdoc="x">current-recorded-disappeared-uses</a></span></span><span class="RktPn"></span><span class="RktPn">)</span></p></blockquote></td></tr><tr><td><span class="hspace"> </span>→<span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fbase..rkt%29._or%2Fc%29%29" class="RktValLink" data-pltdoc="x">or/c</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fbase..rkt%29._listof%29%29" class="RktValLink" data-pltdoc="x">listof</a></span><span class="hspace"> </span><span class="RktSym"><a href="stxops.html#%28def._%28%28lib._racket%2Fprivate%2Fstx..rkt%29._identifier~3f%29%29" class="RktValLink" data-pltdoc="x">identifier?</a></span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fprivate%2Fmisc..rkt%29._false%2Fc%29%29" class="RktValLink" data-pltdoc="x">false/c</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._current-recorded-disappeared-uses%29%29" class="RktValDef RktValLink" data-pltdoc="x">current-recorded-disappeared-uses</a></span></span><span class="hspace"> </span><span class="RktVar">ids</span><span class="RktPn">)</span><span class="hspace"> </span>→<span class="hspace"> </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></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">ids</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fbase..rkt%29._or%2Fc%29%29" class="RktValLink" data-pltdoc="x">or/c</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fbase..rkt%29._listof%29%29" class="RktValLink" data-pltdoc="x">listof</a></span><span class="hspace"> </span><span class="RktSym"><a href="stxops.html#%28def._%28%28lib._racket%2Fprivate%2Fstx..rkt%29._identifier~3f%29%29" class="RktValLink" data-pltdoc="x">identifier?</a></span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fprivate%2Fmisc..rkt%29._false%2Fc%29%29" class="RktValLink" data-pltdoc="x">false/c</a></span><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">Parameter for tracking disappeared uses. Tracking is “enabled” when
|
||
|
|
the parameter has a non-false value. This is done automatically by
|
||
|
|
forms like <span class="RktSym"><a href="syntax-util.html#%28form._%28%28lib._racket%2Fsyntax..rkt%29._with-disappeared-uses%29%29" class="RktStxLink" data-pltdoc="x">with-disappeared-uses</a></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>syntax</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(form._((lib._racket/syntax..rkt)._with-disappeared-uses))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28form._%28%28lib._racket%2Fsyntax..rkt%29._with-disappeared-uses%29%29" class="RktStxDef RktStxLink" data-pltdoc="x">with-disappeared-uses</a></span></span><span class="hspace"> </span><span class="RktVar">body-expr</span><span class="hspace"> </span><span class="RktMeta">...</span><span class="hspace"> </span><span class="RktVar">stx-expr</span><span class="RktPn">)</span></p></blockquote></td></tr><tr><td><span class="stt"> </span></td></tr><tr><td><table cellspacing="0" cellpadding="0" class="argcontract"><tr><td><span class="hspace"> </span></td><td><span class="RktVar">stx-expr</span></td><td><span class="hspace"> </span></td><td>:</td><td><span class="hspace"> </span></td><td><span class="RktSym"><a href="stxops.html#%28def._%28%28quote._~23~25kernel%29._syntax~3f%29%29" class="RktValLink" data-pltdoc="x">syntax?</a></span></td></tr></table></td></tr></table></blockquote></div><div class="SIntrapara">Evaluates the <span class="RktVar">body-expr</span>s and <span class="RktVar">stx-expr</span>, catching identifiers
|
||
|
|
looked up using <span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._syntax-local-value%2Frecord%29%29" class="RktValLink" data-pltdoc="x">syntax-local-value/record</a></span>. Adds the caught identifiers
|
||
|
|
to the <span class="RktVal">'</span><span class="RktVal">disappeared-use</span> syntax property of the syntax object produced
|
||
|
|
by <span class="RktVar">stx-expr</span>.</div></p><p class="SHistory">Changed in version 6.5.0.7 of package <span class="stt">base</span>: Added the option to include <span class="RktVar">body-expr</span>s.</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._((lib._racket/syntax..rkt)._syntax-local-value/record))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._syntax-local-value%2Frecord%29%29" class="RktValDef RktValLink" data-pltdoc="x">syntax-local-value/record</a></span></span><span class="hspace"> </span><span class="RktVar">id</span><span class="hspace"> </span><span class="RktVar">predicate</span><span class="RktPn">)</span><span class="hspace"> </span>→<span class="hspace"> </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"> </span><span class="RktVar">id</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="stxops.html#%28def._%28%28lib._racket%2Fprivate%2Fstx..rkt%29._identifier~3f%29%29" class="RktValLink" data-pltdoc="x">identifier?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">predicate</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="function-contracts.html#%28form._%28%28lib._racket%2Fcontract%2Fbase..rkt%29._-~3e%29%29" class="RktStxLink" data-pltdoc="x"><span class="nobreak">-></span></a></span><span class="hspace"> </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><span class="hspace"> </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><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">Looks up <span class="RktVar">id</span> in the syntactic environment (as
|
||
|
|
<span class="RktSym"><a href="stxtrans.html#%28def._%28%28quote._~23~25kernel%29._syntax-local-value%29%29" class="RktValLink" data-pltdoc="x">syntax-local-value</a></span>). If the lookup succeeds and returns a
|
||
|
|
value satisfying the predicate, the value is returned and <span class="RktVar">id</span>
|
||
|
|
is recorded as a disappeared use by calling <span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._record-disappeared-uses%29%29" class="RktValLink" data-pltdoc="x">record-disappeared-uses</a></span>.
|
||
|
|
If the lookup fails or if the value
|
||
|
|
does not satisfy the predicate, <span class="RktVal">#f</span> is returned and the
|
||
|
|
identifier is not recorded as a disappeared use.</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._((lib._racket/syntax..rkt)._record-disappeared-uses))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._record-disappeared-uses%29%29" class="RktValDef RktValLink" data-pltdoc="x">record-disappeared-uses</a></span></span><span class="hspace"> </span><span class="RktVar">id</span><span class="hspace"> </span><span class="RktOpt">[</span><span class="RktVar">intro?</span><span class="RktOpt">]</span><span class="RktPn">)</span><span class="hspace"> </span>→<span class="hspace"> </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"> </span><span class="RktVar">id</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fbase..rkt%29._or%2Fc%29%29" class="RktValLink" data-pltdoc="x">or/c</a></span><span class="hspace"> </span><span class="RktSym"><a href="stxops.html#%28def._%28%28lib._racket%2Fprivate%2Fstx..rkt%29._identifier~3f%29%29" class="RktValLink" data-pltdoc="x">identifier?</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fbase..rkt%29._listof%29%29" class="RktValLink" data-pltdoc="x">listof</a></span><span class="hspace"> </span><span class="RktSym"><a href="stxops.html#%28def._%28%28lib._racket%2Fprivate%2Fstx..rkt%29._identifier~3f%29%29" class="RktValLink" data-pltdoc="x">identifier?</a></span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">intro?</span><span class="hspace"> </span>:<span class="hspace"> </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><span class="hspace"> </span>=<span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="stxtrans.html#%28def._%28%28quote._~23~25kernel%29._syntax-transforming~3f%29%29" class="RktValLink" data-pltdoc="x">syntax-transforming?</a></span><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">Add <span class="RktVar">id</span> to <span class="RktPn">(</span><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._current-recorded-disappeared-uses%29%29" class="RktValLink" data-pltdoc="x">current-recorded-disappeared-uses</a></span><span class="RktPn">)</span>. If
|
||
|
|
<span class="RktVar">id</span> is a list, perform the same operation on all the
|
||
|
|
identifiers. If <span class="RktVar">intro?</span> is true, then
|
||
|
|
<span class="RktSym"><a href="stxtrans.html#%28def._%28%28quote._~23~25kernel%29._syntax-local-introduce%29%29" class="RktValLink" data-pltdoc="x">syntax-local-introduce</a></span> is first called on the identifiers.</div></p><p>If not used within the extent of a <span class="RktSym"><a href="syntax-util.html#%28form._%28%28lib._racket%2Fsyntax..rkt%29._with-disappeared-uses%29%29" class="RktStxLink" data-pltdoc="x">with-disappeared-uses</a></span>
|
||
|
|
form or similar, has no effect.</p><p class="SHistory">Changed in version 6.5.0.7 of package <span class="stt">base</span>: Added the option to pass a single identifier instead of
|
||
|
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requiring a list.<br/>Changed in version 7.2.0.11: Added the <span class="RktVar">intro?</span> argument.</p><h5 x-source-module="(lib "scribblings/reference/reference.scrbl")" x-source-pkg="racket-doc" x-part-tag=""Miscellaneous_utilities"">12.12.5<tt> </tt><a name="(part._.Miscellaneous_utilities)"></a>Miscellaneous utilities</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._((lib._racket/syntax..rkt)._generate-temporary))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._generate-temporary%29%29" class="RktValDef RktValLink" data-pltdoc="x">generate-temporary</a></span></span><span class="hspace"> </span><span class="RktOpt">[</span><span class="RktVar">name-base</span><span class="RktOpt">]</span><span class="RktPn">)</span><span class="hspace"> </span>→<span class="hspace"> </span><span class="RktSym"><a href="stxops.html#%28def._%28%28lib._racket%2Fprivate%2Fstx..rkt%29._identifier~3f%29%29" class="RktValLink" data-pltdoc="x">identifier?</a></span></p></blockquote></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">name-base</span><span class="hspace"> </span>:<span class="hspace"> </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><span class="hspace"> </span>=<span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">g</span></td></tr></table></blockquote></div><div class="SIntrapara">Generates one fresh identifier. Singular form of
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<span class="RktSym"><a href="stxops.html#%28def._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._generate-temporaries%29%29" class="RktValLink" data-pltdoc="x">generate-temporaries</a></span>. If <span class="RktVar">name-base</span> is supplied, it
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is used as the basis for the identifier’s name.</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><table cellspacing="0" cellpadding="0" class="prototype RForeground"><tr><td valign="top"><span class="RktPn">(</span><a name="(def._((lib._racket/syntax..rkt)._internal-definition-context-apply))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._internal-definition-context-apply%29%29" class="RktValDef RktValLink" data-pltdoc="x">internal-definition-context-apply</a></span></span></td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktVar">intdef-ctx</span></td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="hspace"> </span></td></tr><tr><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktVar">stx</span><span class="RktPn">)</span></td><td valign="top"><span class="hspace"> </span></td><td valign="top">→</td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktSym"><a href="stxops.html#%28def._%28%28quote._~23~25kernel%29._syntax~3f%29%29" class="RktValLink" data-pltdoc="x">syntax?</a></span></td></tr></table></blockquote></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">intdef-ctx</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="stxtrans.html#%28def._%28%28quote._~23~25kernel%29._internal-definition-context~3f%29%29" class="RktValLink" data-pltdoc="x">internal-definition-context?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">stx</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="stxops.html#%28def._%28%28quote._~23~25kernel%29._syntax~3f%29%29" class="RktValLink" data-pltdoc="x">syntax?</a></span></td></tr></table></blockquote></div><div class="SIntrapara">Equivalent to <span class="RktPn">(</span><span class="RktSym"><a href="stxtrans.html#%28def._%28%28quote._~23~25kernel%29._internal-definition-context-introduce%29%29" class="RktValLink" data-pltdoc="x">internal-definition-context-introduce</a></span><span class="stt"> </span><span class="RktVar">intdef-ctx</span><span class="stt"> </span><span class="RktVar">stx</span><span class="stt"> </span><span class="RktVal">'</span><span class="RktVal">add</span><span class="RktPn">)</span>. The
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<span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._internal-definition-context-apply%29%29" class="RktValLink" data-pltdoc="x">internal-definition-context-apply</a></span> function is provided for backwards compatibility; the
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<span class="RktSym"><a href="stxtrans.html#%28def._%28%28quote._~23~25kernel%29._internal-definition-context-add-scopes%29%29" class="RktValLink" data-pltdoc="x">internal-definition-context-add-scopes</a></span> function is preferred.</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._((lib._racket/syntax..rkt)._syntax-local-eval))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._syntax-local-eval%29%29" class="RktValDef RktValLink" data-pltdoc="x">syntax-local-eval</a></span></span><span class="hspace"> </span><span class="RktVar">stx</span><span class="hspace"> </span><span class="RktOpt">[</span><span class="RktVar">intdef-ctx</span><span class="RktOpt">]</span><span class="RktPn">)</span><span class="hspace"> </span>→<span class="hspace"> </span><span class="RktSym"><a href="data-structure-contracts.html#%28form._%28%28lib._racket%2Fcontract%2Fprivate%2Fmisc..rkt%29._any%29%29" class="RktStxLink" data-pltdoc="x">any</a></span></p></blockquote></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">stx</span><span class="hspace"> </span>:<span class="hspace"> </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><table cellspacing="0" cellpadding="0" class="argcontract"><tr><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktVar">intdef-ctx</span></td><td valign="top"><span class="hspace"> </span></td><td valign="top">:</td><td valign="top"><span class="hspace"> </span></td><td valign="top"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="RktPn">(</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fbase..rkt%29._or%2Fc%29%29" class="RktValLink" data-pltdoc="x">or/c</a></span><span class="hspace"> </span><span class="RktSym"><a href="stxtrans.html#%28def._%28%28quote._~23~25kernel%29._internal-definition-context~3f%29%29" class="RktValLink" data-pltdoc="x">internal-definition-context?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVal">#f</span></td></tr><tr><td><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="data-structure-contracts.html#%28def._%28%28lib._racket%2Fcontract%2Fbase..rkt%29._listof%29%29" class="RktValLink" data-pltdoc="x">listof</a></span><span class="hspace"> </span><span class="RktSym"><a href="stxtrans.html#%28def._%28%28quote._~23~25kernel%29._internal-definition-context~3f%29%29" class="RktValLink" data-pltdoc="x">internal-definition-context?</a></span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="hspace"> </span></td><td valign="top">=</td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktVal">'</span><span class="RktVal">(</span><span class="RktVal">)</span></td></tr></table></td></tr></table></blockquote></div><div class="SIntrapara">Evaluates <span class="RktVar">stx</span> as an expression in the current <a href="syntax-model.html#%28tech._transformer._environment%29" class="techoutside" data-pltdoc="x"><span class="techinside">transformer environment</span></a> (that is, at
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<a href="syntax-model.html#%28tech._phase._level%29" class="techoutside" data-pltdoc="x"><span class="techinside">phase level</span></a> 1). If <span class="RktVar">intdef-ctx</span> is not <span class="RktVal">#f</span>, the value provided for
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<span class="RktVar">intdef-ctx</span> is used to enrich <span class="RktVar">stx</span>’s <a href="syntax-model.html#%28tech._lexical._information%29" class="techoutside" data-pltdoc="x"><span class="techinside">lexical information</span></a> and extend the
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<a href="syntax-model.html#%28tech._local._binding._context%29" class="techoutside" data-pltdoc="x"><span class="techinside">local binding context</span></a> in the same way as the fourth argument to <span class="RktSym"><a href="stxtrans.html#%28def._%28%28quote._~23~25kernel%29._local-expand%29%29" class="RktValLink" data-pltdoc="x">local-expand</a></span>.</div></p><p><div class="SIntrapara">Examples:</div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define-syntax%29%29" class="RktStxLink" data-pltdoc="x">define-syntax</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">show-me</span><span class="hspace"> </span><span class="RktVar">stx</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._syntax-case%29%29" class="RktStxLink" data-pltdoc="x">syntax-case</a></span><span class="hspace"> </span><span class="RktVar">stx</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">[</span><span class="RktPn">(</span><span class="RktSym">show-me</span><span class="hspace"> </span><span class="RktSym">expr</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="begin.html#%28form._%28%28quote._~23~25kernel%29._begin%29%29" class="RktStxLink" data-pltdoc="x">begin</a></span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._printf%29%29" class="RktValLink" data-pltdoc="x">printf</a></span><span class="hspace"> </span><span class="RktVal">"at compile time produces ~s\n"</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="syntax-util.html#%28def._%28%28lib._racket%2Fsyntax..rkt%29._syntax-local-eval%29%29" class="RktValLink" data-pltdoc="x">syntax-local-eval</a></span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">expr</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktPn">(</span><span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._printf%29%29" class="RktValLink" data-pltdoc="x">printf</a></span><span class="hspace"> </span><span class="RktVal">"at run time produces ~s\n"</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktSym">expr</span><span class="RktPn">)</span><span class="RktPn">)</span><span class="RktPn">]</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">show-me</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-pl
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contexts in addition to a single internal-definition context or
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<span class="RktVal">#f</span>.</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><table cellspacing="0" cellpadding="0" class="RktBlk RForeground"><tr><td><span class="RktPn">(</span><a name="(form._((lib._racket/syntax..rkt)._with-syntax*))"></a><span title="Provided from: racket/syntax | Package: base"><span class="RktSym"><a href="syntax-util.html#%28form._%28%28lib._racket%2Fsyntax..rkt%29._with-syntax%2A%29%29" class="RktStxDef RktStxLink" data-pltdoc="x">with-syntax*</a></span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">[</span><span class="RktVar">pattern</span><span class="hspace"> </span><span class="RktVar">stx-expr</span><span class="RktPn">]</span><span class="hspace"> </span><span class="RktMeta">...</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">body</span><span class="hspace"> </span><span class="RktMeta">...+</span><span class="RktPn">)</span></td></tr></table></blockquote></td></tr><tr><td><span class="stt"> </span></td></tr><tr><td><table cellspacing="0" cellpadding="0" class="argcontract"><tr><td><span class="hspace"> </span></td><td><span class="RktVar">stx-expr</span></td><td><span class="hspace"> </span></td><td>:</td><td><span class="hspace"> </span></td><td><span class="RktSym"><a href="stxops.html#%28def._%28%28quote._~23~25kernel%29._syntax~3f%29%29" class="RktValLink" data-pltdoc="x">syntax?</a></span></td></tr></table></td></tr></table></blockquote></div><div class="SIntrapara">Similar to <span class="RktSym"><a href="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fstxcase-scheme..rkt%29._with-syntax%29%29" class="RktStxLink" data-pltdoc="x">with-syntax</a></span>, but the pattern variables of each
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<span class="RktVar">pattern</span> are bound in the <span class="RktVar">stx-expr</span>s of subsequent
|
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clauses as well as the <span class="RktVar">body</span>s, and the <span class="RktVar">pattern</span>s need
|
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not bind distinct pattern variables; later bindings shadow earlier
|
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bindings.</div></p><p><div class="SIntrapara">Example:</div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="syntax-util.html#%28form._%28%28lib._racket%2Fsyntax..rkt%29._with-syntax%2A%29%29" class="RktStxLink" data-pltdoc="x">with-syntax*</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">[</span><span class="RktPn">(</span><span class="RktSym">x</span><span class="hspace"> </span><span class="RktSym">y</span><span class="RktPn">)</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="RktRdr">#'</span><span class="RktSym">val1</span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">val2</span><span class="RktPn">)</span><span class="RktPn">]</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">[</span><span class="RktSym">nest</span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktPn">(</span><span class="RktPn">(</span><span class="RktSym">x</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">y</span><span class="RktPn">)</span><span class="RktPn">)</span><span class="RktPn">]</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktRdr">#'</span><span class="RktSym">nest</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><p><span class="RktRes">#<syntax:eval:22:0 ((val1) (val2))></span></p></td></tr></table></blockquote></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="include.html" title="backward to "12.11 File Inclusion"" data-pltdoc="x">← prev</a> <a href="Macros.html" title="up to "12 Macros"" data-pltdoc="x">up</a> <a href="phase_space.html" title="forward to "12.13 Phase and Space Utilities"" data-pltdoc="x">next →</a></span> </div></div></div><div id="contextindicator"> </div></body></html>
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