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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>3.26 Importing Modules Lazily: lazy-require</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="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-pltdoc="x">Unsafe Operations</a></td></tr><tr><td align="right">18 </td><td><a href=
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dynamically requires the export named <span class="RktVar">orig-fun-id</span> from the
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module specified by <span class="RktVar">module-path</span> and calls it with the same
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arguments. If <span class="RktVar">orig-fun-id</span> is not given, it defaults to
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<span class="RktVar">fun-id</span>.</div></p><p>If the enclosing relative phase level is not 0, then
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<span class="RktVar">module-path</span> is also placed in a submodule (with a use of
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<span class="RktSym"><a href="Filesystem.html#%28form._%28%28lib._racket%2Fruntime-path..rkt%29._define-runtime-module-path-index%29%29" class="RktStxLink" data-pltdoc="x">define-runtime-module-path-index</a></span> at phase level 0 within the
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submodule). Introduced submodules have the names
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<span class="RktSym">lazy-require-aux</span><span class="RktVar">n</span><span class="RktSym">-</span><span class="RktVar">m</span>, where
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<span class="RktVar">n</span> is a phase-level number and <span class="RktVar">m</span> is a number.</p><p>When the use of a lazily-required function triggers module loading, it
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also triggers a use of <span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=raco&rel=cm-accomplice.html%23%2528def._%2528%2528lib._compiler%252Fcm-accomplice..rkt%2529._register-external-module%2529%2529&version=8.6" class="RktValLink Sq" data-pltdoc="x">register-external-module</a></span> to declare an
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indirect compilation dependency (in case the function is used in the
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process of compiling a module).</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="lazy-require.html#%28form._%28%28lib._racket%2Flazy-require..rkt%29._lazy-require%29%29" class="RktStxLink" data-pltdoc="x">lazy-require</a></span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">[</span><span class="RktSym">racket/list</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="pairs.html#%28def._%28%28lib._racket%2Flist..rkt%29._partition%29%29" class="RktValLink" data-pltdoc="x">partition</a></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"><a href="pairs.html#%28def._%28%28lib._racket%2Flist..rkt%29._partition%29%29" class="RktValLink" data-pltdoc="x">partition</a></span><span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._even~3f%29%29" class="RktValLink" data-pltdoc="x">even?</a></span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">(</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="hspace"> </span><span class="RktVal">4</span><span class="hspace"> </span><span class="RktVal">5</span><span class="RktVal">)</span><span class="RktPn">)</span></td></tr><tr><td><table cellspacing="0" cellpadding="0"><tr><td><p><span class="RktRes">'(2 4)</span></p></td></tr><tr><td><p><span class="RktRes">'(1 3 5)</span></p></td></tr></table></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="module.html#%28form._%28%28quote._~23~25kernel%29._module%29%29" class="RktStxLink" data-pltdoc="x">module</a></span><span class="hspace"> </span><span class="RktSym">hello</span><span class="hspace"> </span><span class="RktSym">racket/base</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="require.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._provide%29%29" class="RktStxLink" data-pltdoc="x">provide</a></span><span class="hspace"> </span><span class="RktSym">hello</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="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">"starting hello server\n"</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="define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define%29%29" class="RktStxLink" data-pltdoc="x">define</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">hello</span><span class="RktPn">)</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">"hello!\n"</span><span class="RktPn">)</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="stt">
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<span class="RktVar">macro-id</span> as a macro that, when used, dynamically loads the
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macro’s implementation from the given <span class="RktVar">module-path</span>. If
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<span class="RktVar">orig-macro-id</span> is not given, it defaults to <span class="RktVar">macro-id</span>.</div></p><p>Use <span class="RktSym"><a href="lazy-require.html#%28form._%28%28lib._racket%2Flazy-require..rkt%29._lazy-require-syntax%29%29" class="RktStxLink" data-pltdoc="x">lazy-require-syntax</a></span> in the <span class="emph">implementation</span> of a library
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with large, complicated macros to avoid a dependence from clients of
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the library on the macro “compilers.” Note that only macros with
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exceptionally large compile-time components (such as Typed Racket,
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which includes a type checker and optimizer) benefit from
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<span class="RktSym"><a href="lazy-require.html#%28form._%28%28lib._racket%2Flazy-require..rkt%29._lazy-require-syntax%29%29" class="RktStxLink" data-pltdoc="x">lazy-require-syntax</a></span>; typical macros do not.</p><p><div class="SIntrapara"><span style="font-weight: bold">Warning:</span> <span class="RktSym"><a href="lazy-require.html#%28form._%28%28lib._racket%2Flazy-require..rkt%29._lazy-require-syntax%29%29" class="RktStxLink" data-pltdoc="x">lazy-require-syntax</a></span> breaks the invariants
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that Racket’s module loader and linker rely on; these invariants
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normally ensure that the references in code produced by a macro are
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loaded before the code runs. Safe use of <span class="RktSym"><a href="lazy-require.html#%28form._%28%28lib._racket%2Flazy-require..rkt%29._lazy-require-syntax%29%29" class="RktStxLink" data-pltdoc="x">lazy-require-syntax</a></span>
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requires a particular structure in the macro implementation. (In
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particular, <span class="RktSym"><a href="lazy-require.html#%28form._%28%28lib._racket%2Flazy-require..rkt%29._lazy-require-syntax%29%29" class="RktStxLink" data-pltdoc="x">lazy-require-syntax</a></span> cannot simply be introduced
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in the client code.) The macro implementation must follow these rules:
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</div><div class="SIntrapara"><ol><li><p>the interface module must <span class="RktSym"><a href="require.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._require%29%29" class="RktStxLink" data-pltdoc="x">require</a></span> the runtime-support module</p></li><li><p>the compiler module must <span class="RktSym"><a href="require.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._require%29%29" class="RktStxLink" data-pltdoc="x">require</a></span> the runtime-support module via
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an <span class="emph">absolute</span> module path rather than a <span class="emph">relative</span> path</p></li></ol></div></p><p><div class="SIntrapara">To explain the concepts of “interface, compiler, and runtime-support
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modules”, here is an example module that exports a macro:
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</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="module.html#%28form._%28%28quote._~23~25kernel%29._module%29%29" class="RktStxLink" data-pltdoc="x">module</a></span><span class="hspace"> </span><span class="RktSym">original</span><span class="hspace"> </span><span class="RktSym">racket/base</span></td></tr><tr><td><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define%29%29" class="RktStxLink" data-pltdoc="x">define</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">ntimes-proc</span><span class="hspace"> </span><span class="RktSym">n</span><span class="hspace"> </span><span class="RktSym"><a href="procedures.html#%28form._%28%28lib._racket%2Ffunction..rkt%29._thunk%29%29" class="RktStxLink" data-pltdoc="x">thunk</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="for.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._for%29%29" class="RktStxLink" data-pltdoc="x">for</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">[</span><span class="RktSym">i</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="sequences.html#%28def._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._in-range%29%29" class="RktValLink" data-pltdoc="x">in-range</a></span><span class="hspace"> </span><span class="RktSym">n</span><span class="RktPn">)</span><span class="RktPn">]</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="procedures.html#%28form._%28%28lib._racket%2Ffunction..rkt%29._thunk%29%29" class="RktStxLink" data-pltdoc="x">thunk</a></span><span class="RktPn">)</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%2Fmisc..rkt%29._define-syntax-rule%29%29" class="RktStxLink" data-pltdoc="x">define-syntax-rule</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">ntimes</span><span class="hspace"> </span><span class="RktSym">n</span><span class="hspace"> </span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=syntax&rel=Library_Syntax_Classes_and_Literal_Sets.html%23%2528form._%2528%2528lib._syntax%252Fparse..rkt%2529._expr%2529%2529&version=8.6" class="RktStxLink Sq" data-pltdoc="x">expr</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">ntimes-proc</span><span class="hspace"> </span><span class="RktSym">n</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="lambda.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._lambda%29%29" class="RktStxLink" data-pltdoc="x">lambda</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=syntax&rel=Library_Syntax_Classes_and_Literal_Sets.html%23%2528form._%2528%2528lib._syntax%252Fparse..rkt%2529._expr%2529%2529&version=8.6" class="RktStxLink Sq" data-pltdoc="x">expr</a></span><span class="RktPn">)</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="require.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._provide%29%29" class="RktStxLink" data-pltdo
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implementation of the <span class="RktSym">ntimes</span> macro transformer. The original
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module must be split into three parts:
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</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="module.html#%28form._%28%28quote._~23~25kernel%29._module%29%29" class="RktStxLink" data-pltdoc="x">module</a></span><span class="hspace"> </span><span class="RktSym">runtime-support</span><span class="hspace"> </span><span class="RktSym">racket/base</span></td></tr><tr><td><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define%29%29" class="RktStxLink" data-pltdoc="x">define</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">ntimes-proc</span><span class="hspace"> </span><span class="RktSym">n</span><span class="hspace"> </span><span class="RktSym"><a href="procedures.html#%28form._%28%28lib._racket%2Ffunction..rkt%29._thunk%29%29" class="RktStxLink" data-pltdoc="x">thunk</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="for.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._for%29%29" class="RktStxLink" data-pltdoc="x">for</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">[</span><span class="RktSym">i</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="sequences.html#%28def._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._in-range%29%29" class="RktValLink" data-pltdoc="x">in-range</a></span><span class="hspace"> </span><span class="RktSym">n</span><span class="RktPn">)</span><span class="RktPn">]</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="procedures.html#%28form._%28%28lib._racket%2Ffunction..rkt%29._thunk%29%29" class="RktStxLink" data-pltdoc="x">thunk</a></span><span class="RktPn">)</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="require.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._provide%29%29" class="RktStxLink" data-pltdoc="x">provide</a></span><span class="hspace"> </span><span class="RktSym">ntimes-proc</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPn">(</span><span class="RktSym"><a href="module.html#%28form._%28%28quote._~23~25kernel%29._module%29%29" class="RktStxLink" data-pltdoc="x">module</a></span><span class="hspace"> </span><span class="RktSym">compiler</span><span class="hspace"> </span><span class="RktSym">racket/base</span></td></tr><tr><td><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="require.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._require%29%29" class="RktStxLink" data-pltdoc="x">require</a></span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">runtime-support</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%2Fmisc..rkt%29._define-syntax-rule%29%29" class="RktStxLink" data-pltdoc="x">define-syntax-rule</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">ntimes</span><span class="hspace"> </span><span class="RktSym">n</span><span class="hspace"> </span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=syntax&rel=Library_Syntax_Classes_and_Literal_Sets.html%23%2528form._%2528%2528lib._syntax%252Fparse..rkt%2529._expr%2529%2529&version=8.6" class="RktStxLink Sq" data-pltdoc="x">expr</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace">  
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that the macro refers to. The compiler module contains the macro
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definition(s) themselves—<wbr></wbr>the part of the code that “disappears”
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after compile time. The interface module lazily loads the macro
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transformer, but it makes sure the runtime support module is defined at
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run time by requiring it normally. In a larger example, of course, the
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runtime support and compiler may both consist of multiple modules.</div></p><p><div class="SIntrapara">Here what happens when we don’t separate the runtime support into a
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separate module:
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</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="module.html#%28form._%28%28quote._~23~25kernel%29._module%29%29" class="RktStxLink" data-pltdoc="x">module</a></span><span class="hspace"> </span><span class="RktSym">bad-no-runtime</span><span class="hspace"> </span><span class="RktSym">racket/base</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define%29%29" class="RktStxLink" data-pltdoc="x">define</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">ntimes-proc</span><span class="hspace"> </span><span class="RktSym">n</span><span class="hspace"> </span><span class="RktSym"><a href="procedures.html#%28form._%28%28lib._racket%2Ffunction..rkt%29._thunk%29%29" class="RktStxLink" data-pltdoc="x">thunk</a></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="for.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._for%29%29" class="RktStxLink" data-pltdoc="x">for</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">[</span><span class="RktSym">i</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="sequences.html#%28def._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._in-range%29%29" class="RktValLink" data-pltdoc="x">in-range</a></span><span class="hspace"> </span><span class="RktSym">n</span><span class="RktPn">)</span><span class="RktPn">]</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="procedures.html#%28form._%28%28lib._racket%2Ffunction..rkt%29._thunk%29%29" class="RktStxLink" data-pltdoc="x">thunk</a></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="stx-patterns.html#%28form._%28%28lib._racket%2Fprivate%2Fmisc..rkt%29._define-syntax-rule%29%29" class="RktStxLink" data-pltdoc="x">define-syntax-rule</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">ntimes</span><span class="hspace"> </span><span class="RktSym">n</span><span class="hspace"> </span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=syntax&rel=Library_Syntax_Classes_and_Literal_Sets.html%23%2528form._%2528%2528lib._syntax%252Fparse..rkt%2529._expr%2529%2529&version=8.6" class="RktStxLink Sq" data-pltdoc="x">expr</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">ntimes-proc</span><span class="hspace"> </span><span class="RktSym">n</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="lambda.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._lambda%29%29" class="RktStxLink" data-pltdoc="x">lambda</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktPn">)</span><span class="hspace"> </span><span class="RktSym"><a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=syntax&rel=Library_Syntax_Classes_and_Literal_Sets.html%23%2528form._%2528%2528lib._syntax%252Fparse..rkt%2529._expr%2529%2529&version=8.6" class="RktStxLink Sq" data-pltdoc="x">expr</a></span><span class="RktPn">)</span><span class="RktPn">)</s
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dependency on the runtime support module.</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="performance-hint.html" title="backward to "3.25 Performance Hints: begin-encourage-inline"" data-pltdoc="x">← prev</a> <a href="syntax.html" title="up to "3 Syntactic Forms"" data-pltdoc="x">up</a> <a href="data.html" title="forward to "4 Datatypes"" data-pltdoc="x">next →</a></span> </div></div></div><div id="contextindicator"> </div></body></html>
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