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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>13.6 Pretty Printing</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="tocviewlink" data-pltdoc="x">Macros</a></td></tr><tr><td align="right">13 </td><td><a href="input-and-output.html" class="tocviewselflink" 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="tocviewlink" data-pltdoc="x">Running Racket</a></td></tr><tr><td align="right"></td><td><a href="doc-bibliography.html" class="tocviewlink" data-pltdoc="x">Bibliography</a></td></tr><tr><td align="right"></td><td><a href="doc-index.html" class="tocviewlink" data-pltdoc="x">Index</a></td></tr></table></div></div><div class="tocviewlist"><table cellspacing="0" cellpadding="0"><tr><td style="width: 1em;"><a href="javascript:void(0);" title="Expand/Collapse" class="tocviewtoggle" onclick="TocviewToggle(this,"tocview_1");">▼</a></td><td>13 </td><td><a href="input-and-output.html" class="tocviewlink" data-pltdoc="x">Input and Output</a></td></tr></table><div class="tocviewsublist" style="display: block;" id="tocview_1"><table cellspacing="0" cellpadding="0"><tr><td align="right">13.1 </td><td><a href="ports.html" class="tocviewlink" data-pltdoc="x">Ports</a></td></tr><tr><td align="right">13.2 </td><td><a href="Byte_and_String_Input.html" class="tocviewlink" data-pltdoc="x">Byte and String Input</a></td></tr><tr><td align="right">13.3 </td><td><a href="Byte_and_String_Output.html" class="tocviewlink" data-pltdoc="x">Byte and String Output</a></td></tr><tr><td align="right">13.4 </td><td><a href="Reading.html" class="tocviewlink" data-pltdoc="x">Reading</a></td></tr><tr><td align="right">13.5 </td><td><a href="Writing.html" class="tocviewlink" data-pltdoc="x">Writing</a></td></tr><tr><td align="right">13.6 </td><td><a href="pretty-print.html" class="tocviewselflink" data-pltdoc="x">Pretty Printing</a></td></tr><tr><td align="right">13.7 </td><td><a href="Reader_Extension.html" class="tocviewlink" data-pltdoc="x">Reader Extension</a></td></tr><tr><td align="right">13.8 </td><td><a href="Printer_Extension.html" class="tocviewlink" data-pltdoc="x">Printer Extension</a></td></tr><tr><td align="right">13.9 </td><td><a href="serialization.html" class="tocviewlink" data-pltdoc="x">Serialization</a></td></tr><tr><td align="right">13.10 </td><td><a href="fasl.html" class="tocviewlink" data-pltdoc="x">Fast-<wbr></wbr>Load Serialization</a></td></tr><tr><td align="right">13.11 </td><td><a href="sha.html" class="tocviewlink" data-pltdoc="x">Cryptographic Hashing</a></td></tr></table></div></div><div class="tocviewlist"><table cellspacing="0" cellpadding="0"><tr><td style="width: 1em;"><a href="javascript:void(0);" title="Expand/Collapse" class="tocviewtoggle" onclick="TocviewToggle(this,"tocview_2");">►</a></td><td>13.6 </td><td><a href="pretty-print.html" class="tocviewselflink" data-pltdoc="x">Pretty Printing</a></td></tr></table><div class="tocviewsublistbottom" style="display: none;" id="tocview_2"><table cellspacing="0" cellpadding="0"><tr><td align="right">13.6.1 </td><td><a href="pretty-print.html#%28part._.Basic_.Pretty-.Print_.Options%29" class="tocviewlink" data-pltdoc="x">Basic Pretty-<wbr></wbr>Print Options</a></td></tr><tr><td align="right">13.6.2 </td><td><a href="pretty-print.html#%28part._.Per-.Symbol_.Special_.Printing%29" class="tocviewlink" data-pltdoc="x">Per-<wbr></wbr>Symbol Special Printing</a></td></tr><tr><td align="right">13.6.3 </td><td><a href="pretty-print.html#%28part._.Line-.Output_.Hook%29" class="tocviewlink" data-pltdoc="x">Line-<wbr></wbr>Output Hook</a></td></tr><tr><td align="right">13.6.4 </td><td><a href="pretty-print.html#%28part._.Value_.Output_.Hook%29" class="tocviewlink" data-pltdoc="x">Value Output Hook</a></td></tr><tr><td align="right">13.6.5 </td><td><a href="pretty-print.html#%28part._.Additional_.Custom-.Output_.Support%29" class="tocviewlink" data-pltdoc="x">Additional Custom-<wbr></wbr>Output Support</a></td></tr></table></div></div></div><div class="tocsub"><div class="tocsubtitle">On this page:</div><table class="tocsublist" cellspacing="0"><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-write%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>write</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-display%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>display</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-format%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>format</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-handler%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>handler</span></span></a></td></tr><tr><td><span class="tocsublinknumber">13.6.1<tt> </tt></span><a href="pretty-print.html#%28part._.Basic_.Pretty-.Print_.Options%29" class="tocsubseclink" data-pltdoc="x">Basic Pretty-<wbr></wbr>Print Options</a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-columns%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>columns</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-depth%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>depth</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-exact-as-decimal%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>exact-<wbr></wbr>as-<wbr></wbr>decimal</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-..-symbol-without-bars%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>.-<wbr></wbr>symbol-<wbr></wbr>without-<wbr></wbr>bars</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-show-inexactness%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>show-<wbr></wbr>inexactness</span></span></a></td></tr><tr><td><span class="tocsublinknumber">13.6.2<tt> </tt></span><a href="pretty-print.html#%28part._.Per-.Symbol_.Special_.Printing%29" class="tocsubseclink" data-pltdoc="x">Per-<wbr></wbr>Symbol Special Printing</a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-abbreviate-read-macros%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>abbreviate-<wbr></wbr>read-<wbr></wbr>macros</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-style-table~3f%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>style-<wbr></wbr>table?</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-current-style-table%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>current-<wbr></wbr>style-<wbr></wbr>table</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-extend-style-table%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>extend-<wbr></wbr>style-<wbr></wbr>table</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-remap-stylable%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>remap-<wbr></wbr>stylable</span></span></a></td></tr><tr><td><span class="tocsublinknumber">13.6.3<tt> </tt></span><a href="pretty-print.html#%28part._.Line-.Output_.Hook%29" class="tocsubseclink" data-pltdoc="x">Line-<wbr></wbr>Output Hook</a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-newline%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>newline</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-line%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>print-<wbr></wbr>line</span></span></a></td></tr><tr><td><span class="tocsublinknumber">13.6.4<tt> </tt></span><a href="pretty-print.html#%28part._.Value_.Output_.Hook%29" class="tocsubseclink" data-pltdoc="x">Value Output Hook</a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-size-hook%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>size-<wbr></wbr>hook</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-hook%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>print-<wbr></wbr>hook</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-pre-print-hook%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>pre-<wbr></wbr>print-<wbr></wbr>hook</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-post-print-hook%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>print-<wbr></wbr>post-<wbr></wbr>print-<wbr></wbr>hook</span></span></a></td></tr><tr><td><span class="tocsublinknumber">13.6.5<tt> </tt></span><a href="pretty-print.html#%28part._.Additional_.Custom-.Output_.Support%29" class="tocsubseclink" data-pltdoc="x">Additional Custom-<wbr></wbr>Output Support</a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-printing%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">pretty-<wbr></wbr>printing</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._make-tentative-pretty-print-output-port%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">make-<wbr></wbr>tentative-<wbr></wbr>pretty-<wbr></wbr>print-<wbr></wbr>output-<wbr></wbr>port</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._tentative-pretty-print-port-transfer%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">tentative-<wbr></wbr>pretty-<wbr></wbr>print-<wbr></wbr>port-<wbr></wbr>transfer</span></span></a></td></tr><tr><td><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._tentative-pretty-print-port-cancel%29%29" class="tocsubnonseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">tentative-<wbr></wbr>pretty-<wbr></wbr>print-<wbr></wbr>port-<wbr></wbr>cancel</span></span></a></td></tr></table></div></div><div class="maincolumn"><div class="main"><div class="navsettop"><span class="navleft"><form class="searchform"><input class="searchbox" 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="Writing.html" title="backward to "13.5 Writing"" data-pltdoc="x">← prev</a> <a href="input-and-output.html" title="up to "13 Input and Output"" data-pltdoc="x">up</a> <a href="Reader_Extension.html" title="forward to "13.7 Reader Extension"" data-pltdoc="x">next →</a></span> </div><h4 x-source-module="(lib "scribblings/reference/reference.scrbl")" x-source-pkg="racket-doc" x-part-tag=""pretty-print"">13.6<tt> </tt><a name="(part._pretty-print)"></a><a name="(mod-path._racket/pretty)"></a>Pretty Printing</h4><p><div class="SIntrapara"><table cellspacing="0" cellpadding="0" class="defmodule"><tr><td align="left"><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="stt"> </span><a href="pretty-print.html" class="RktModLink" data-pltdoc="x"><span class="RktSym">racket/pretty</span></a><span class="RktPn">)</span></td><td align="right"><span class="RpackageSpec"><span class="Smaller"> package:</span> <a href="https://pkgs.racket-lang.org/package/base" title="Install this package using `raco pkg install base`"><span class="stt">base</span></a></span></td></tr></table></div><div class="SIntrapara">The bindings documented in this section are provided by the <a href="pretty-print.html" class="RktModLink" data-pltdoc="x"><span class="RktSym">racket/pretty</span></a> and <a href="index.html" class="RktModLink" data-pltdoc="x"><span class="RktSym">racket</span></a> libraries, but not <a href="index.html" class="RktModLink" data-pltdoc="x"><span class="RktSym">racket/base</span></a>.</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/pretty..rkt)._pretty-print))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print</a></span></span></td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktVar">v</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><span class="RktOpt">[</span></td><td valign="top"><span class="RktVar">port</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">quote-depth</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="RktPn">#:newline?</span><span class="hspace"> </span><span class="RktVar">newline?</span><span class="RktOpt">]</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="void.html#%28def._%28%28quote._~23~25kernel%29._void~3f%29%29" class="RktValLink" data-pltdoc="x">void?</a></span></td></tr></table></blockquote></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><tr><td><span class="hspace"> </span><span class="RktVar">port</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span><span class="hspace"> </span>=<span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._current-output-port%29%29" class="RktValLink" data-pltdoc="x">current-output-port</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">quote-depth</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="RktVal">0</span><span class="hspace"> </span><span class="RktVal">1</span><span class="RktPn">)</span><span class="hspace"> </span>=<span class="hspace"> </span><span class="RktVal">0</span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">newline?</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="RktVal">#t</span></td></tr></table></blockquote></div><div class="SIntrapara">Pretty-prints the value <span class="RktVar">v</span> using the same printed form as the
|
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default <span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._print%29%29" class="RktValLink" data-pltdoc="x">print</a></span> mode, but with newlines and whitespace inserted
|
|
to avoid lines longer than <span class="RktPn">(</span><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-columns%29%29" class="RktValLink" data-pltdoc="x">pretty-print-columns</a></span><span class="RktPn">)</span>, as
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|
controlled by <span class="RktPn">(</span><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-current-style-table%29%29" class="RktValLink" data-pltdoc="x">pretty-print-current-style-table</a></span><span class="RktPn">)</span>. The printed
|
|
form ends in a newline by default, unless the <span class="RktVar">newline?</span>
|
|
argument is supplied with false or the <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-columns%29%29" class="RktValLink" data-pltdoc="x">pretty-print-columns</a></span>
|
|
parameter is set to <span class="RktVal">'</span><span class="RktVal">infinity</span>. When <span class="RktVar">port</span> has line
|
|
counting enabled (see <a href="linecol.html" data-pltdoc="x">Counting Positions, Lines, and Columns</a>), then printing is sensitive
|
|
to the column when printing starts—<wbr></wbr>both for determining an initial
|
|
line break and indenting subsequent lines.</div></p><p>In addition to the parameters defined in this section,
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span> conforms to the <span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._print-graph%29%29" class="RktValLink" data-pltdoc="x">print-graph</a></span>,
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|
<span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._print-struct%29%29" class="RktValLink" data-pltdoc="x">print-struct</a></span>, <span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._print-hash-table%29%29" class="RktValLink" data-pltdoc="x">print-hash-table</a></span>,
|
|
<span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._print-vector-length%29%29" class="RktValLink" data-pltdoc="x">print-vector-length</a></span>, <span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._print-box%29%29" class="RktValLink" data-pltdoc="x">print-box</a></span>, and
|
|
<span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._print-as-expression%29%29" class="RktValLink" data-pltdoc="x">print-as-expression</a></span> parameters.</p><p>The pretty printer detects structures that have the
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|
<span class="RktSym"><a href="Printer_Extension.html#%28def._%28%28quote._~23~25kernel%29._prop~3acustom-write%29%29" class="RktValLink" data-pltdoc="x">prop:custom-write</a></span> property and calls the corresponding
|
|
custom-write procedure. The custom-write procedure can check the
|
|
parameter <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-printing%29%29" class="RktValLink" data-pltdoc="x">pretty-printing</a></span> to cooperate with the
|
|
pretty-printer. Recursive printing to the port automatically uses
|
|
pretty printing, but if the structure has multiple recursively printed
|
|
sub-expressions, a custom-write procedure may need to cooperate more
|
|
to insert explicit newlines. Use <span class="RktSym"><a href="linecol.html#%28def._%28%28quote._~23~25kernel%29._port-next-location%29%29" class="RktValLink" data-pltdoc="x">port-next-location</a></span> to
|
|
determine the current output column, use <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-columns%29%29" class="RktValLink" data-pltdoc="x">pretty-print-columns</a></span>
|
|
to determine the target printing width, and use
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-newline%29%29" class="RktValLink" data-pltdoc="x">pretty-print-newline</a></span> to insert a newline (so that the
|
|
function in the <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-line%29%29" class="RktValLink" data-pltdoc="x">pretty-print-print-line</a></span> parameter can be
|
|
called appropriately). Use
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._make-tentative-pretty-print-output-port%29%29" class="RktValLink" data-pltdoc="x">make-tentative-pretty-print-output-port</a></span> to obtain a port for
|
|
tentative recursive prints (e.g., to check the length of the output).</p><p>If the <span class="RktVar">newline?</span> argument is omitted or supplied with true,
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|
the <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-line%29%29" class="RktValLink" data-pltdoc="x">pretty-print-print-line</a></span> callback is called with false as
|
|
the first argument to print the last newline after the printed value.
|
|
If it is supplied with false, the <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-line%29%29" class="RktValLink" data-pltdoc="x">pretty-print-print-line</a></span>
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callback is not called after the printed value.</p><p class="SHistory">Changed in version 6.6.0.3 of package <span class="stt">base</span>: Added <span class="RktVar">newline?</span> argument.</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/pretty..rkt)._pretty-write))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-write%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-write</a></span></span><span class="hspace"> </span><span class="RktVar">v</span><span class="hspace"> </span><span class="RktOpt">[</span><span class="RktVar">port</span><span class="hspace"> </span><span class="RktPn">#:newline?</span><span class="hspace"> </span><span class="RktVar">newline?</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">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><tr><td><span class="hspace"> </span><span class="RktVar">port</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span><span class="hspace"> </span>=<span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._current-output-port%29%29" class="RktValLink" data-pltdoc="x">current-output-port</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">newline?</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="RktVal">#t</span></td></tr></table></blockquote></div><div class="SIntrapara">Same as <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span>, but <span class="RktVar">v</span> is printed like
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<span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._write%29%29" class="RktValLink" data-pltdoc="x">write</a></span> instead of like <span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._print%29%29" class="RktValLink" data-pltdoc="x">print</a></span>.</div></p><p class="SHistory">Changed in version 6.6.0.3 of package <span class="stt">base</span>: Added <span class="RktVar">newline?</span> argument.</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/pretty..rkt)._pretty-display))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-display%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-display</a></span></span><span class="hspace"> </span><span class="RktVar">v</span><span class="hspace"> </span><span class="RktOpt">[</span><span class="RktVar">port</span><span class="hspace"> </span><span class="RktPn">#:newline?</span><span class="hspace"> </span><span class="RktVar">newline?</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">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><tr><td><span class="hspace"> </span><span class="RktVar">port</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span><span class="hspace"> </span>=<span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._current-output-port%29%29" class="RktValLink" data-pltdoc="x">current-output-port</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">newline?</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="RktVal">#t</span></td></tr></table></blockquote></div><div class="SIntrapara">Same as <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span>, but <span class="RktVar">v</span> is printed like
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<span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._display%29%29" class="RktValLink" data-pltdoc="x">display</a></span> instead of like <span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._print%29%29" class="RktValLink" data-pltdoc="x">print</a></span>.</div></p><p class="SHistory">Changed in version 6.6.0.3 of package <span class="stt">base</span>: Added <span class="RktVar">newline?</span> argument.</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/pretty..rkt)._pretty-format))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-format%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-format</a></span></span><span class="hspace"> </span><span class="RktVar">v</span><span class="hspace"> </span><span class="RktOpt">[</span><span class="RktVar">columns</span><span class="hspace"> </span><span class="RktPn">#:mode</span><span class="hspace"> </span><span class="RktVar">mode</span><span class="RktOpt">]</span><span class="RktPn">)</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></p></blockquote></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><tr><td><span class="hspace"> </span><span class="RktVar">columns</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="hspace"> </span>=<span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-columns%29%29" class="RktValLink" data-pltdoc="x">pretty-print-columns</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">mode</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="RktVal">'</span><span class="RktVal">print</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">write</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">display</span><span class="RktPn">)</span><span class="hspace"> </span>=<span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">print</span></td></tr></table></blockquote></div><div class="SIntrapara">Like <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span>, except that it returns a string containing
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the pretty-printed value, rather than sending the output to a port.</div></p><p>The optional argument <span class="RktVar">columns</span> argument is used to
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|
parameterize <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-columns%29%29" class="RktValLink" data-pltdoc="x">pretty-print-columns</a></span>.</p><p>The keyword argument <span class="RktVar">mode</span> controls whether printing is done like
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|
either <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span> (the default), <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-write%29%29" class="RktValLink" data-pltdoc="x">pretty-write</a></span> or
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-display%29%29" class="RktValLink" data-pltdoc="x">pretty-display</a></span>.</p><p class="SHistory">Changed in version 6.3 of package <span class="stt">base</span>: Added a <span class="RktVar">mode</span> argument.</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/pretty..rkt)._pretty-print-handler))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-handler%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-handler</a></span></span><span class="hspace"> </span><span class="RktVar">v</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">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">Pretty-prints <span class="RktVar">v</span> if <span class="RktVar">v</span> is not <a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=guide&rel=void_undefined.html&version=8.6" class="RktModLink Sq" data-pltdoc="x"><span class="nobreak"><span class="RktRes">#<void></span></span></a>, or prints
|
|
nothing if <span class="RktVar">v</span> is <a href="https://download.racket-lang.org/releases/8.6/doc/local-redirect/index.html?doc=guide&rel=void_undefined.html&version=8.6" class="RktModLink Sq" data-pltdoc="x"><span class="nobreak"><span class="RktRes">#<void></span></span></a>. Pass this procedure to
|
|
<span class="RktSym"><a href="eval.html#%28def._%28%28quote._~23~25kernel%29._current-print%29%29" class="RktValLink" data-pltdoc="x">current-print</a></span> to install the pretty printer into the REPL run
|
|
by <span class="RktSym"><a href="eval.html#%28def._%28%28lib._racket%2Fprivate%2Fmisc..rkt%29._read-eval-print-loop%29%29" class="RktValLink" data-pltdoc="x">read-eval-print-loop</a></span>.</div></p><h5 x-source-module="(lib "scribblings/reference/reference.scrbl")" x-source-pkg="racket-doc" x-part-tag=""Basic_Pretty-Print_Options"">13.6.1<tt> </tt><a name="(part._.Basic_.Pretty-.Print_.Options)"></a>Basic Pretty-Print Options</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/pretty..rkt)._pretty-print-columns))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-columns%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-columns</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="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-positive-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-positive-integer?</a></span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">infinity</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-columns%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-columns</a></span></span><span class="hspace"> </span><span class="RktVar">width</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">width</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="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-positive-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-positive-integer?</a></span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">infinity</span><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that determines the default width for pretty printing.</div></p><p>If the display width is <span class="RktVal">'</span><span class="RktVal">infinity</span>, then pretty-printed output
|
|
is never broken into lines, and a newline is not added to the end of
|
|
the output.</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>parameter</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-depth))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-depth%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-depth</a></span></span><span class="RktPn"></span><span class="RktPn">)</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="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="hspace"> </span><span class="RktVal">#f</span><span class="RktPn">)</span></p></blockquote></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-depth%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-depth</a></span></span><span class="hspace"> </span><span class="RktVar">depth</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">depth</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="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="hspace"> </span><span class="RktVal">#f</span><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">Parameter that controls the default depth for recursive pretty
|
|
printing. Printing to <span class="RktVar">depth</span> means that elements nested more
|
|
deeply than <span class="RktVar">depth</span> are replaced with “...”; in particular, a
|
|
depth of <span class="RktVal">0</span> indicates that only simple values are printed. A depth of
|
|
<span class="RktVal">#f</span> (the default) allows printing to arbitrary
|
|
depths.</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>parameter</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-exact-as-decimal))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-exact-as-decimal%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-exact-as-decimal</a></span></span><span class="RktPn"></span><span class="RktPn">)</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></p></blockquote></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-exact-as-decimal%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-exact-as-decimal</a></span></span><span class="hspace"> </span><span class="RktVar">as-decimal?</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">as-decimal?</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">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that determines how exact non-integers are printed. If
|
|
the parameter’s value is <span class="RktVal">#t</span>, then an exact non-integer with a
|
|
decimal representation is printed as a decimal number instead of a
|
|
fraction. The initial value is <span class="RktVal">#f</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>parameter</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-..-symbol-without-bars))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-..-symbol-without-bars%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-.-symbol-without-bars</a></span></span><span class="RktPn"></span><span class="RktPn">)</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></p></blockquote></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-..-symbol-without-bars%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-.-symbol-without-bars</a></span></span><span class="hspace"> </span><span class="RktVar">on?</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">on?</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">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that controls the printing of the symbol whose print name
|
|
is just a period. If set to a true value, then such a symbol is
|
|
printed as only the period. If set to a false value, it is printed as
|
|
a period with vertical bars surrounding it.</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>parameter</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-show-inexactness))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-show-inexactness%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-show-inexactness</a></span></span><span class="RktPn"></span><span class="RktPn">)</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></p></blockquote></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-show-inexactness%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-show-inexactness</a></span></span><span class="hspace"> </span><span class="RktVar">show?</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">show?</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">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that determines how inexact numbers are printed. If the
|
|
parameter’s value is <span class="RktVal">#t</span>, then inexact numbers are always
|
|
printed with a leading <span class="RktInBG"><span class="hspace"></span><span class="RktIn">#i</span><span class="hspace"></span></span>. The initial value is <span class="RktVal">#f</span>.</div></p><h5 x-source-module="(lib "scribblings/reference/reference.scrbl")" x-source-pkg="racket-doc" x-part-tag=""Per-Symbol_Special_Printing"">13.6.2<tt> </tt><a name="(part._.Per-.Symbol_.Special_.Printing)"></a>Per-Symbol Special Printing</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/pretty..rkt)._pretty-print-abbreviate-read-macros))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-abbreviate-read-macros%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-abbreviate-read-macros</a></span></span><span class="RktPn"></span><span class="RktPn">)</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></p></blockquote></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-abbreviate-read-macros%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-abbreviate-read-macros</a></span></span><span class="hspace"> </span><span class="RktVar">abbrev?</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">abbrev?</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">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that controls whether or not <span class="RktSym">quote</span>,
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|
<span class="RktSym">unquote</span>, <span class="RktSym">unquote-splicing</span>, etc<span class="Sendabbrev">.</span>, are
|
|
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>, <span class="RktInBG"><span class="hspace"></span><span class="RktIn">,@</span><span class="hspace"></span></span>, etc.
|
|
By default, the abbreviations are enabled.</div></p><p>See also <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-remap-stylable%29%29" class="RktValLink" data-pltdoc="x">pretty-print-remap-stylable</a></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>procedure</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-style-table~3f))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-style-table~3f%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-style-table?</a></span></span><span class="hspace"> </span><span class="RktVar">v</span><span class="RktPn">)</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></p></blockquote></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">Returns <span class="RktVal">#t</span> if <span class="RktVar">v</span> is a style table for use with
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-current-style-table%29%29" class="RktValLink" data-pltdoc="x">pretty-print-current-style-table</a></span>, <span class="RktVal">#f</span> otherwise.</div></p><p><div class="SIntrapara"><blockquote class="SVInsetFlow"><table cellspacing="0" cellpadding="0" class="boxed RBoxed"><tr><td><blockquote class="SubFlow"><div class="RBackgroundLabel SIEHidden"><div class="RBackgroundLabelInner"><p>parameter</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-current-style-table))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-current-style-table%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-current-style-table</a></span></span><span class="RktPn"></span><span class="RktPn">)</span><span class="hspace"> </span>→<span class="hspace"> </span><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-style-table~3f%29%29" class="RktValLink" data-pltdoc="x">pretty-print-style-table?</a></span></p></blockquote></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-current-style-table%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-current-style-table</a></span></span><span class="hspace"> </span><span class="RktVar">style-table</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">style-table</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-style-table~3f%29%29" class="RktValLink" data-pltdoc="x">pretty-print-style-table?</a></span></td></tr></table></blockquote></div><div class="SIntrapara">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that holds a table of style mappings. See
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-extend-style-table%29%29" class="RktValLink" data-pltdoc="x">pretty-print-extend-style-table</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><table cellspacing="0" cellpadding="0" class="prototype RForeground"><tr><td valign="top"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-extend-style-table))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-extend-style-table%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-extend-style-table</a></span></span></td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktVar">style-table</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">symbol-list</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">like-symbol-list</span><span class="RktPn">)</span></td><td valign="top"><span class="hspace"> </span></td></tr></table></blockquote></td></tr><tr><td><span class="hspace"> </span>→<span class="hspace"> </span><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-style-table~3f%29%29" class="RktValLink" data-pltdoc="x">pretty-print-style-table?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">style-table</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-style-table~3f%29%29" class="RktValLink" data-pltdoc="x">pretty-print-style-table?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">symbol-list</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._listof%29%29" class="RktValLink" data-pltdoc="x">listof</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="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">like-symbol-list</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._listof%29%29" class="RktValLink" data-pltdoc="x">listof</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="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">Creates a new style table by extending an existing
|
|
<span class="RktVar">style-table</span>, so that the style mapping for each symbol of
|
|
<span class="RktVar">like-symbol-list</span> in the original table is used for the
|
|
corresponding symbol of <span class="RktVar">symbol-list</span> in the new table. The
|
|
<span class="RktVar">symbol-list</span> and <span class="RktVar">like-symbol-list</span> lists must have the
|
|
same length. The <span class="RktVar">style-table</span> argument can be <span class="RktVal">#f</span>, in
|
|
which case the default mappings are used from the original table (see
|
|
below).</div></p><p>The style mapping for a symbol controls the way that whitespace is
|
|
inserted when printing a list that starts with the symbol. In the
|
|
absence of any mapping, when a list is broken across multiple lines,
|
|
each element of the list is printed on its own line, each with the
|
|
same indentation.</p><p>The default style mapping includes mappings for the following symbols,
|
|
so that the output follows popular code-formatting rules:</p><blockquote class="SCodeFlow"><table cellspacing="0" cellpadding="0" class="RktBlk"><tr><td><span class="RktVal">'</span><span class="RktVal">lambda</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">λ</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">case-lambda</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">define</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">define-macro</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">define-syntax</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">let</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">letrec</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">let*</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">let-syntax</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">letrec-syntax</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">let-values</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">letrec-values</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">let*-values</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">let-syntaxes</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">letrec-syntaxes</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">begin</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">begin0</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">do</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">if</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">set!</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">set!-values</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">unless</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">when</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">cond</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">case</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">and</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">or</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">module</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">syntax-rules</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">syntax-case</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">letrec-syntaxes+values</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">import</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">export</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">link</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">require</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">require-for-syntax</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">require-for-template</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">provide</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">public</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">private</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">override</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">rename</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">inherit</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">field</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">init</span></td></tr><tr><td><span class="RktVal">'</span><span class="RktVal">shared</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">send</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">class</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">instantiate</span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">make-object</span></td></tr></table></blockquote><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/pretty..rkt)._pretty-print-remap-stylable))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-remap-stylable%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-remap-stylable</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%2Fprivate%2Fmisc..rkt%29._any%2Fc%29%29" class="RktValLink" data-pltdoc="x">any/c</a></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="RktPn"> .</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="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="RktVal">#f</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-remap-stylable%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-remap-stylable</a></span></span><span class="hspace"> </span><span class="RktVar">proc</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">proc</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%2Fprivate%2Fmisc..rkt%29._any%2Fc%29%29" class="RktValLink" data-pltdoc="x">any/c</a></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="RktPn"> .</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="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="RktVal">#f</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that controls remapping for styles and for the determination of
|
|
the reader shorthands.</div></p><p>This procedure is
|
|
called with each sub-expression that appears as the first element in a
|
|
sequence. If it returns a symbol, the style table is used, as if that
|
|
symbol were at the head of the sequence. If it returns <span class="RktVal">#f</span>,
|
|
the style table is treated normally.
|
|
Similarly, when determining whether to abbreviate reader macros,
|
|
this parameter is consulted.</p><h5 x-source-module="(lib "scribblings/reference/reference.scrbl")" x-source-pkg="racket-doc" x-part-tag=""Line-Output_Hook"">13.6.3<tt> </tt><a name="(part._.Line-.Output_.Hook)"></a>Line-Output Hook</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/pretty..rkt)._pretty-print-newline))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-newline%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-newline</a></span></span><span class="hspace"> </span><span class="RktVar">port</span><span class="hspace"> </span><span class="RktVar">width</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">port</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">width</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span></td></tr></table></blockquote></div><div class="SIntrapara">Calls the procedure associated with the
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-line%29%29" class="RktValLink" data-pltdoc="x">pretty-print-print-line</a></span> parameter to print a newline to
|
|
<span class="RktVar">port</span>, if <span class="RktVar">port</span> is the output port that is redirected
|
|
to the original output port for printing, otherwise a plain newline is
|
|
printed to <span class="RktVar">port</span>. The <span class="RktVar">width</span> argument should be the
|
|
target column width, typically obtained from
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-columns%29%29" class="RktValLink" data-pltdoc="x">pretty-print-columns</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>parameter</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-print-line))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-line%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-print-line</a></span></span><span class="RktPn"></span><span class="RktPn">)</span></p></blockquote></td></tr><tr><td><table cellspacing="0" cellpadding="0" class="prototype"><tr><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="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="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="hspace"> </span><span class="RktVal">#f</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></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._or%2Fc%29%29" class="RktValLink" data-pltdoc="x">or/c</a></span><span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">infinity</span><span class="RktPn">)</span></td></tr><tr><td><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="RktPn"> .</span></td></tr><tr><td><span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="RktPn">)</span></td></tr></table></td></tr></table></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-line%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-print-line</a></span></span><span class="hspace"> </span><span class="RktVar">proc</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><table cellspacing="0" cellpadding="0" class="argcontract"><tr><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktVar">proc</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="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="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="hspace"> </span><span class="RktVal">#f</span><span class="RktPn">)</span></td></tr><tr><td><span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></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._or%2Fc%29%29" class="RktValLink" data-pltdoc="x">or/c</a></span><span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">infinity</span><span class="RktPn">)</span></td></tr><tr><td><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="RktPn"> .</span></td></tr><tr><td><span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="RktPn">)</span></td></tr></table></td></tr></table></td></tr></table></blockquote></div><div class="SIntrapara">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that determines a procedure for printing the newline
|
|
separator between lines of a pretty-printed value. The procedure is
|
|
called with four arguments: a new line number, an output port, the old
|
|
line’s length, and the number of destination columns. The return value
|
|
from <span class="RktVar">proc</span> is the number of extra characters it printed at the
|
|
beginning of the new line.</div></p><p>The <span class="RktVar">proc</span> procedure is called before any characters are
|
|
printed with <span class="RktVal">0</span> as the line number and <span class="RktVal">0</span> as the old
|
|
line length. Whenever the pretty-printer starts a new line,
|
|
<span class="RktVar">proc</span> is called with the new line’s number (where the first
|
|
new line is numbered <span class="RktVal">1</span>) and the just-finished line’s length.
|
|
The destination-columns argument to <span class="RktVar">proc</span> is always
|
|
the total width of the destination printing area, or
|
|
<span class="RktVal">'</span><span class="RktVal">infinity</span> if pretty-printed values are not broken into lines.</p><p>If the <span class="RktPn">#:newline?</span> argument was omitted or supplied with
|
|
a true value, <span class="RktVar">proc</span> is also called after the last character of the
|
|
value has been printed, with <span class="RktVal">#f</span> as the line number and with
|
|
the length of the last line.</p><p>The default <span class="RktVar">proc</span> procedure prints a newline whenever the line
|
|
number is not <span class="RktVal">0</span> and the column count is not
|
|
<span class="RktVal">'</span><span class="RktVal">infinity</span>, always returning <span class="RktVal">0</span>. A custom
|
|
<span class="RktVar">proc</span> procedure can be used to print extra text before each
|
|
line of pretty-printed output; the number of characters printed before
|
|
each line should be returned by <span class="RktVar">proc</span> so that the next line
|
|
break can be chosen correctly.</p><p>The destination port supplied to <span class="RktVar">proc</span> is generally not the
|
|
port supplied to <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span> or <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-display%29%29" class="RktValLink" data-pltdoc="x">pretty-display</a></span> (or
|
|
the current output port), but output to this port is ultimately
|
|
redirected to the port supplied to <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span> or
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-display%29%29" class="RktValLink" data-pltdoc="x">pretty-display</a></span>.</p><h5 x-source-module="(lib "scribblings/reference/reference.scrbl")" x-source-pkg="racket-doc" x-part-tag=""Value_Output_Hook"">13.6.4<tt> </tt><a name="(part._.Value_.Output_.Hook)"></a>Value Output Hook</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/pretty..rkt)._pretty-print-size-hook))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-size-hook%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-size-hook</a></span></span><span class="RktPn"></span><span class="RktPn">)</span></p></blockquote></td></tr><tr><td><table cellspacing="0" cellpadding="0" class="prototype"><tr><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%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="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span></td></tr><tr><td><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="RktPn"> .</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._or%2Fc%29%29" class="RktValLink" data-pltdoc="x">or/c</a></span><span class="hspace"> </span><span class="RktVal">#f</span><span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr></table></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-size-hook%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-size-hook</a></span></span><span class="hspace"> </span><span class="RktVar">proc</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><table cellspacing="0" cellpadding="0" class="argcontract"><tr><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktVar">proc</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%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="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span></td></tr><tr><td><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="RktPn"> .</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._or%2Fc%29%29" class="RktValLink" data-pltdoc="x">or/c</a></span><span class="hspace"> </span><span class="RktVal">#f</span><span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr></table></td></tr></table></blockquote></div><div class="SIntrapara">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that determines a sizing hook for pretty-printing.</div></p><p>The sizing hook is applied to each value to be printed. If the hook
|
|
returns <span class="RktVal">#f</span>, then printing is handled internally by the
|
|
pretty-printer. Otherwise, the value should be an integer specifying
|
|
the length of the printed value in characters; the print hook will be
|
|
called to actually print the value (see
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-hook%29%29" class="RktValLink" data-pltdoc="x">pretty-print-print-hook</a></span>).</p><p>The sizing hook receives three arguments. The first argument is the
|
|
value to print. The second argument is a boolean: <span class="RktVal">#t</span> for
|
|
printing like <span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._display%29%29" class="RktValLink" data-pltdoc="x">display</a></span> and <span class="RktVal">#f</span> for printing like
|
|
<span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._write%29%29" class="RktValLink" data-pltdoc="x">write</a></span>. The third argument is the destination port; the port
|
|
is the one supplied to <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span> or
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-display%29%29" class="RktValLink" data-pltdoc="x">pretty-display</a></span> (or the current output port). The sizing hook
|
|
may be applied to a single value multiple times during
|
|
pretty-printing.</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>parameter</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-print-hook))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-hook%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-print-hook</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%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="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></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="RktPn"> .</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><span class="RktPn">)</span></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-print-hook%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-print-hook</a></span></span><span class="hspace"> </span><span class="RktVar">proc</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">proc</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%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="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></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="RktPn"> .</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><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that determines a print hook for pretty-printing. The
|
|
print-hook procedure is applied to a value for printing when the
|
|
sizing hook (see <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-size-hook%29%29" class="RktValLink" data-pltdoc="x">pretty-print-size-hook</a></span>) returns an integer
|
|
size for the value.</div></p><p>The print hook receives three arguments. The first argument is the
|
|
value to print. The second argument is a boolean: <span class="RktVal">#t</span> for
|
|
printing like <span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._display%29%29" class="RktValLink" data-pltdoc="x">display</a></span> and <span class="RktVal">#f</span> for printing like
|
|
<span class="RktSym"><a href="Writing.html#%28def._%28%28quote._~23~25kernel%29._write%29%29" class="RktValLink" data-pltdoc="x">write</a></span>. The third argument is the destination port; this port
|
|
is generally not the port supplied to <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span> or
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-display%29%29" class="RktValLink" data-pltdoc="x">pretty-display</a></span> (or the current output port), but output to
|
|
this port is ultimately redirected to the port supplied to
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span> or <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-display%29%29" class="RktValLink" data-pltdoc="x">pretty-display</a></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>parameter</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-pre-print-hook))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-pre-print-hook%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-pre-print-hook</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%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="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></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="RktPn"> .</span><span class="hspace"> </span><span class="RktSym"><a href="void.html#%28def._%28%28quote._~23~25kernel%29._void%29%29" class="RktValLink" data-pltdoc="x">void</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-pre-print-hook%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-pre-print-hook</a></span></span><span class="hspace"> </span><span class="RktVar">proc</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">proc</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%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="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></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="RktPn"> .</span><span class="hspace"> </span><span class="RktSym"><a href="void.html#%28def._%28%28quote._~23~25kernel%29._void%29%29" class="RktValLink" data-pltdoc="x">void</a></span><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that determines a hook procedure to be called just before
|
|
an object is printed. The hook receives two arguments: the object and
|
|
the output port. The port is the one supplied to <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span>
|
|
or <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-display%29%29" class="RktValLink" data-pltdoc="x">pretty-display</a></span> (or the current output port).</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>parameter</p></div></div><p class="RForeground"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._pretty-print-post-print-hook))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-post-print-hook%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-post-print-hook</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%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="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></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="RktPn"> .</span><span class="hspace"> </span><span class="RktSym"><a href="void.html#%28def._%28%28quote._~23~25kernel%29._void%29%29" class="RktValLink" data-pltdoc="x">void</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-post-print-hook%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-print-post-print-hook</a></span></span><span class="hspace"> </span><span class="RktVar">proc</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">proc</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%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="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></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="RktPn"> .</span><span class="hspace"> </span><span class="RktSym"><a href="void.html#%28def._%28%28quote._~23~25kernel%29._void%29%29" class="RktValLink" data-pltdoc="x">void</a></span><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that determines a hook procedure to be called just after
|
|
an object is printed. The hook receives two arguments: the object and
|
|
the output port. The port is the one supplied to <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print%29%29" class="RktValLink" data-pltdoc="x">pretty-print</a></span>
|
|
or <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-display%29%29" class="RktValLink" data-pltdoc="x">pretty-display</a></span> (or the current output port).</div></p><h5 x-source-module="(lib "scribblings/reference/reference.scrbl")" x-source-pkg="racket-doc" x-part-tag=""Additional_Custom-Output_Support"">13.6.5<tt> </tt><a name="(part._.Additional_.Custom-.Output_.Support)"></a>Additional Custom-Output Support</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/pretty..rkt)._pretty-printing))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-printing%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-printing</a></span></span><span class="RktPn"></span><span class="RktPn">)</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></p></blockquote></td></tr><tr><td><span class="RktPn">(</span><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-printing%29%29" class="RktValDef RktValLink" data-pltdoc="x">pretty-printing</a></span></span><span class="hspace"> </span><span class="RktVar">on?</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">on?</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">A <a href="eval-model.html#%28tech._parameter%29" class="techoutside" data-pltdoc="x"><span class="techinside">parameter</span></a> that is set to <span class="RktVal">#t</span> when the pretty printer calls a
|
|
custom-write procedure (see <span class="RktSym"><a href="Printer_Extension.html#%28def._%28%28quote._~23~25kernel%29._prop~3acustom-write%29%29" class="RktValLink" data-pltdoc="x">prop:custom-write</a></span>) for output in
|
|
a mode that supports line breaks. When pretty printer calls a
|
|
custom-write procedure merely to detect cycles or to try to print on a
|
|
single line, it sets this parameter to <span class="RktVal">#f</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><table cellspacing="0" cellpadding="0" class="prototype RForeground"><tr><td valign="top"><span class="RktPn">(</span><a name="(def._((lib._racket/pretty..rkt)._make-tentative-pretty-print-output-port))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._make-tentative-pretty-print-output-port%29%29" class="RktValDef RktValLink" data-pltdoc="x">make-tentative-pretty-print-output-port</a></span></span></td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktVar">out</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">width</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">overflow-thunk</span><span class="RktPn">)</span></td><td valign="top"><span class="hspace"> </span></td></tr></table></blockquote></td></tr><tr><td><span class="hspace"> </span>→<span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">out</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">width</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="number-types.html#%28def._%28%28quote._~23~25kernel%29._exact-nonnegative-integer~3f%29%29" class="RktValLink" data-pltdoc="x">exact-nonnegative-integer?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">overflow-thunk</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#%28form._%28%28lib._racket%2Fcontract%2Fprivate%2Fmisc..rkt%29._any%29%29" class="RktStxLink" data-pltdoc="x">any</a></span><span class="RktPn">)</span></td></tr></table></blockquote></div><div class="SIntrapara">Produces an output port that is suitable for recursive pretty printing
|
|
without actually producing output. Use such a port to tentatively
|
|
print when proper output depends on the size of recursive
|
|
prints. After printing, determine the size of the tentative output
|
|
using <span class="RktSym"><a href="port-buffers.html#%28def._%28%28quote._~23~25kernel%29._file-position%29%29" class="RktValLink" data-pltdoc="x">file-position</a></span>.</div></p><p>The <span class="RktVar">out</span> argument should be a pretty-printing port, such as
|
|
the one supplied to a custom-write procedure when
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-printing%29%29" class="RktValLink" data-pltdoc="x">pretty-printing</a></span> is set to true, or another tentative output
|
|
port. The <span class="RktVar">width</span> argument should be a target column width,
|
|
usually obtained from <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-columns%29%29" class="RktValLink" data-pltdoc="x">pretty-print-columns</a></span>, possibly
|
|
decremented to leave room for a terminator. The
|
|
<span class="RktVar">overflow-thunk</span> procedure is called if more than
|
|
<span class="RktVar">width</span> items are printed to the port or if a newline is
|
|
printed to the port via <span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._pretty-print-newline%29%29" class="RktValLink" data-pltdoc="x">pretty-print-newline</a></span>; it can escape from the
|
|
recursive print through a continuation as a shortcut, but
|
|
<span class="RktVar">overflow-thunk</span> can also return, in which case it is called
|
|
every time afterward that additional output is written to the port.</p><p>After tentative printing, either accept the result with
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._tentative-pretty-print-port-transfer%29%29" class="RktValLink" data-pltdoc="x">tentative-pretty-print-port-transfer</a></span> or reject it with
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._tentative-pretty-print-port-cancel%29%29" class="RktValLink" data-pltdoc="x">tentative-pretty-print-port-cancel</a></span>. Failure to accept or
|
|
cancel properly interferes with graph-structure printing, calls to
|
|
hook procedures, etc. Explicitly cancel the tentative print even when
|
|
<span class="RktVar">overflow-thunk</span> escapes from a recursive print.</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/pretty..rkt)._tentative-pretty-print-port-transfer))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._tentative-pretty-print-port-transfer%29%29" class="RktValDef RktValLink" data-pltdoc="x">tentative-pretty-print-port-transfer</a></span></span></td><td valign="top"><span class="hspace"> </span></td><td valign="top"><span class="RktVar">tentative-out</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">orig-out</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="void.html#%28def._%28%28quote._~23~25kernel%29._void~3f%29%29" class="RktValLink" data-pltdoc="x">void?</a></span></td></tr></table></blockquote></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">tentative-out</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span></td></tr><tr><td><span class="hspace"> </span><span class="RktVar">orig-out</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span></td></tr></table></blockquote></div><div class="SIntrapara">Causes the data written to <span class="RktVar">tentative-out</span> to be transferred as
|
|
if written to <span class="RktVar">orig-out</span>. The <span class="RktVar">tentative-out</span> argument
|
|
should be a port produced by
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._make-tentative-pretty-print-output-port%29%29" class="RktValLink" data-pltdoc="x">make-tentative-pretty-print-output-port</a></span>, and
|
|
<span class="RktVar">orig-out</span> should be either a pretty-printing port (provided to
|
|
a custom-write procedure) or another tentative output port.</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/pretty..rkt)._tentative-pretty-print-port-cancel))"></a><span title="Provided from: racket/pretty, racket | Package: base"><span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._tentative-pretty-print-port-cancel%29%29" class="RktValDef RktValLink" data-pltdoc="x">tentative-pretty-print-port-cancel</a></span></span><span class="hspace"> </span><span class="RktVar">tentative-out</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">tentative-out</span><span class="hspace"> </span>:<span class="hspace"> </span><span class="RktSym"><a href="port-ops.html#%28def._%28%28quote._~23~25kernel%29._output-port~3f%29%29" class="RktValLink" data-pltdoc="x">output-port?</a></span></td></tr></table></blockquote></div><div class="SIntrapara">Cancels the content of <span class="RktVar">tentative-out</span>, which was produced by
|
|
<span class="RktSym"><a href="pretty-print.html#%28def._%28%28lib._racket%2Fpretty..rkt%29._make-tentative-pretty-print-output-port%29%29" class="RktValLink" data-pltdoc="x">make-tentative-pretty-print-output-port</a></span>. The main effect of
|
|
canceling is that graph-reference definitions are undone, so that a
|
|
future print of a graph-referenced object includes the defining
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