commit ee83e25307c4925a47700d6ddfe3144b3073a4db
parent c53ec68a676d730f094c1b6d7d6f12b392b657c4
Author: Greg Hendershott <greghendershott@gmail.com>
Date: Tue, 25 Mar 2014 08:53:09 -0400
Regen HTML
Diffstat:
3 files changed, 9 insertions(+), 11 deletions(-)
diff --git a/Robust_macros__syntax-parse.html b/Robust_macros__syntax-parse.html
@@ -6,8 +6,7 @@ message from <span class="RktSym"><a href="http://docs.racket-lang.org/reference
could probably guess what’s happening, but in most cases they won’t.</p><p>2. Write some error handling code.</p><blockquote class="SCodeFlow"><table cellspacing="0" class="RktBlk"><tr><td><table cellspacing="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define%29%29" class="RktStxLink" data-pltdoc="x">define</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktSym">s</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/when_unless.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._unless%29%29" class="RktStxLink" data-pltdoc="x">unless</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string~3f%29%29" class="RktValLink" data-pltdoc="x">string?</a></span><span class="hspace"> </span><span class="RktSym">s</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/exns.html#%28def._%28%28quote._~23~25kernel%29._error%29%29" class="RktValLink" data-pltdoc="x">error</a></span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">misuse</span><span class="hspace"> </span><span class="RktVal">"expected a string, but got ~a"</span><span class="hspace"> </span><span class="RktSym">s</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string-append%29%29" class="RktValLink" data-pltdoc="x">string-append</a></span><span class="hspace"> </span><span class="RktSym">s</span><span class="hspace"> </span><span class="RktVal">" snazzy suffix"</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">User of the function:</span></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktVal">0</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktErr">misuse: expected a string, but got 0</span></p></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">I goofed, and understand why! It</span><span class="RktCmt">'</span><span class="RktCmt">s a shame the writer of the</span></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">function had to work so hard to tell me.</span></td></tr></table></blockquote><p>Unfortunately the error code tends to overwhelm and/or obscure our
function definition. Also, the error message is good but not
great. Improving it would require even more error code.</p><p>3. Use a contract.</p><blockquote class="SCodeFlow"><table cellspacing="0" class="RktBlk"><tr><td><table cellspacing="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/attaching-contracts-to-values.html#%28form._%28%28lib._racket%2Fcontract%2Fregion..rkt%29._define%2Fcontract%29%29" class="RktStxLink" data-pltdoc="x">define/contract</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktSym">s</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string~3f%29%29" class="RktValLink" data-pltdoc="x">string?</a></span><span class="hspace"> </span><span class="RktPn">. </span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/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="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string~3f%29%29" class="RktValLink" data-pltdoc="x">string?</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string-append%29%29" class="RktValLink" data-pltdoc="x">string-append</a></span><span class="hspace"> </span><span class="RktSym">s</span><span class="hspace"> </span><span class="RktVal">" snazzy suffix"</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">User of the function:</span></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktVal">0</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktErr">misuse: contract violation</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">expected: string?</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">given: 0</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">in: the 1st argument of</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">(-> string? string?)</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">contract from: (function misuse)</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">blaming: program</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">at: eval:131.0</span></p></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">I goofed, and understand why! I</span><span class="RktCmt">'</span><span class="RktCmt">m happier, and I hear the writer of</span></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">the function is happier, too.</span></td></tr></table></blockquote><p>This is the best of both worlds.</p><p>The contract is a simple and concise. Even better, it’s
-declarative. We say what we want, without needing to spell out what to
-do.</p><p>On the other hand the user of our function gets a very detailed error
+declarative. We say what we want to happen, not how.</p><p>On the other hand the user of our function gets a very detailed error
message. Plus, the message is in a standard, familiar format.</p><p>4. Use Typed Racket.</p><p><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" class="RktBlk"><tr><td><span class="RktMeta">#lang</span><span class="hspace"> </span><span class="RktMeta"></span><a href="http://docs.racket-lang.org/ts-reference/index.html" class="RktModLink" data-pltdoc="x"><span class="RktSym">typed/racket</span></a><span class="RktMeta"></span></td></tr></table></blockquote></div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">:</span><span class="hspace"> </span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">String</span><span class="hspace"> </span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/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">String</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><table cellspacing="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define%29%29" class="RktStxLink" data-pltdoc="x">define</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktSym">s</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string-append%29%29" class="RktValLink" data-pltdoc="x">string-append</a></span><span class="hspace"> </span><span class="RktSym">s</span><span class="hspace"> </span><span class="RktVal">" snazzy suffix"</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktVal">0</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktErr">eval:3:0: Type Checker: Expected String, but got Zero</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">in: 0</span></p></td></tr></table></blockquote></div></p><p>Even better, Typed Racket can catch usage mistakes up-front at compile
time.</p><h4>7.2<tt> </tt><a name="(part._.Error-handling_strategies_for_macros)"></a>Error-handling strategies for macros</h4><p>For macros, we have similar choices.</p><p>1. Ignore the possibility of misuse. This choice is even worse for
macros. The default error messages are even less likely to make sense,
@@ -27,8 +26,8 @@ confused.</p><blockquote class="SCodeFlow"><table cellspacing="0" class="RktBlk"
with many simple examples, followed by an
<a href="http://docs.racket-lang.org/syntax/stxparse-examples.html">Examples</a>
section illustrating many real-world scenarios.</p><p>Furthermore, everything I’d learned up to this point prepared me to
-appreciate what <span class="RktSym"><a href="http://docs.racket-lang.org/syntax/Parsing_Syntax.html#%28form._%28%28lib._syntax%2Fparse..rkt%29._syntax-parse%29%29" class="RktStxLink" data-pltdoc="x">syntax-parse</a></span> does, and why. That leaves
-the "how" of using it, which seems pretty straightforward, so far.</p><p>This might well be a temporary state of me "not knowing what I don’t
+appreciate what <span class="RktSym"><a href="http://docs.racket-lang.org/syntax/Parsing_Syntax.html#%28form._%28%28lib._syntax%2Fparse..rkt%29._syntax-parse%29%29" class="RktStxLink" data-pltdoc="x">syntax-parse</a></span> does, and why. The details of
+how to use it seem pretty straightforward, so far.</p><p>This might well be a temporary state of me "not knowing what I don’t
know". As I dig in and use it more, maybe I’ll discover something
confusing or tricky. If/when I do, I’ll come back here and update
this.</p><p>But for now I’ll focus on improving the previous parts.</p><div class="navsetbottom"><span class="navleft"> </span><span class="navright"> <a href="What_s_the_point_of_splicing-let_.html" title="backward to "6 What's the point of splicing-let?"" data-pltdoc="x">← prev</a> <a href="index.html" title="up to "Fear of Macros"" data-pltdoc="x">up</a> <a href="References_and_Acknowledgments.html" title="forward to "8 References and Acknowledgments"" data-pltdoc="x">next →</a></span> </div></div></div><div id="contextindicator"> </div></body></html>
\ No newline at end of file
diff --git a/all.html b/all.html
@@ -1,6 +1,6 @@
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"/><title>Fear of Macros</title><link rel="stylesheet" type="text/css" href="scribble.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="gh.css" title="default"/><script type="text/javascript" src="scribble-common.js"></script><!--[if IE 6]><style type="text/css">.SIEHidden { overflow: hidden; }</style><![endif]--><meta name="keywords" content="Racket,macros,Scheme"><meta name="description" content="Practical Racket macros"><meta name="author" content="Greg Hendershott"><meta name="charset" content="utf-8"><link href='http://fonts.googleapis.com/css?family=Fenix' rel='stylesheet' type='text/css'><script type="text/javascript">var _gaq = _gaq || [];_gaq.push(['_setAccount', 'UA-29709446-1']);_gaq.push(['_setDomainName', 'greghendershott.com']);_gaq.push(['_trackPageview']);(function() {var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);})();</script></head><body id="scribble-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="" class="tocviewselflink" data-pltdoc="x">Fear of Macros</a></td></tr></table></div><div class="tocviewsublistonly" style="display: none;" id="tocview_0"><table cellspacing="0" cellpadding="0"><tr><td align="right">1 </td><td><a href="#%28part._.Preface%29" class="tocviewlink" data-pltdoc="x">Preface</a></td></tr><tr><td align="right">2 </td><td><a href="#%28part._.Our_plan_of_attack%29" class="tocviewlink" data-pltdoc="x">Our plan of attack</a></td></tr><tr><td align="right">3 </td><td><a href="#%28part._.Transform_%29" class="tocviewlink" data-pltdoc="x">Transform!</a></td></tr><tr><td align="right">4 </td><td><a href="#%28part._pattern-matching%29" class="tocviewlink" data-pltdoc="x">Pattern matching:<span class="mywbr"> </span> syntax-<wbr></wbr>case and syntax-<wbr></wbr>rules</a></td></tr><tr><td align="right">5 </td><td><a href="#%28part._.Syntax_parameters%29" class="tocviewlink" data-pltdoc="x">Syntax parameters</a></td></tr><tr><td align="right">6 </td><td><a href="#%28part._.What_s_the_point_of_splicing-let_%29" class="tocviewlink" data-pltdoc="x">What’s the point of <span class="RktSym"><span class="RktStxLink">splicing-<wbr></wbr>let</span></span>?</a></td></tr><tr><td align="right">7 </td><td><a href="#%28part._.Robust_macros__syntax-parse%29" class="tocviewlink" data-pltdoc="x">Robust macros:<span class="mywbr"> </span> syntax-<wbr></wbr>parse</a></td></tr><tr><td align="right">8 </td><td><a href="#%28part._.References_and_.Acknowledgments%29" class="tocviewlink" data-pltdoc="x">References and Acknowledgments</a></td></tr><tr><td align="right">9 </td><td><a href="#%28part._.Epilogue%29" class="tocviewlink" data-pltdoc="x">Epilogue</a></td></tr></table></div></div></div><div class="tocsub"><table class="tocsublist" cellspacing="0"><tr><td><span class="tocsublinknumber"></span><a href="#%28part._.Fear_of_.Macros%29" class="tocsubseclink" data-pltdoc="x">Fear of Macros</a></td></tr><tr><td><span class="tocsublinknumber">1<tt> </tt></span><a href="#%28part._.Preface%29" class="tocsubseclink" data-pltdoc="x">Preface</a></td></tr><tr><td><span class="tocsublinknumber">2<tt> </tt></span><a href="#%28part._.Our_plan_of_attack%29" class="tocsubseclink" data-pltdoc="x">Our plan of attack</a></td></tr><tr><td><span class="tocsublinknumber">3<tt> </tt></span><a href="#%28part._.Transform_%29" class="tocsubseclink" data-pltdoc="x">Transform!</a></td></tr><tr><td><span class="tocsublinknumber">3.1<tt> </tt></span><a href="#%28part._.What_is_a_syntax_transformer_%29" class="tocsubseclink" data-pltdoc="x">What is a syntax transformer?</a></td></tr><tr><td><span class="tocsublinknumber">3.2<tt> </tt></span><a href="#%28part._.What_s_the_input_%29" class="tocsubseclink" data-pltdoc="x">What’s the input?</a></td></tr><tr><td><span class="tocsublinknumber">3.3<tt> </tt></span><a href="#%28part._.Actually_transforming_the_input%29" class="tocsubseclink" data-pltdoc="x">Actually transforming the input</a></td></tr><tr><td><span class="tocsublinknumber">3.4<tt> </tt></span><a href="#%28part._.Compile_time_vs__run_time%29" class="tocsubseclink" data-pltdoc="x">Compile time vs. run time</a></td></tr><tr><td><span class="tocsublinknumber">3.5<tt> </tt></span><a href="#%28part._begin-for-syntax%29" class="tocsubseclink" data-pltdoc="x"><span class="RktSym"><span class="RktStxLink">begin-<wbr></wbr>for-<wbr></wbr>syntax</span></span></a></td></tr><tr><td><span class="tocsublinknumber">4<tt> </tt></span><a href="#%28part._pattern-matching%29" class="tocsubseclink" data-pltdoc="x">Pattern matching:<span class="mywbr"> </span> syntax-<wbr></wbr>case and syntax-<wbr></wbr>rules</a></td></tr><tr><td><span class="tocsublinknumber">4.1<tt> </tt></span><a href="#%28part._.Pattern_variable_vs__template---fight_%29" class="tocsubseclink" data-pltdoc="x">Pattern variable vs. template—<wbr></wbr>fight!</a></td></tr><tr><td><span class="tocsublinknumber">4.1.1<tt> </tt></span><a href="#%28part._with-syntax%29" class="tocsubseclink" data-pltdoc="x"><span class="RktSym"><span class="RktStxLink">with-<wbr></wbr>syntax</span></span></a></td></tr><tr><td><span class="tocsublinknumber">4.1.2<tt> </tt></span><a href="#%28part._with-syntax_%29" class="tocsubseclink" data-pltdoc="x"><span class="RktSym"><span class="RktStxLink">with-<wbr></wbr>syntax*</span></span></a></td></tr><tr><td><span class="tocsublinknumber">4.1.3<tt> </tt></span><a href="#%28part._format-id%29" class="tocsubseclink" data-pltdoc="x"><span class="RktSym"><span class="RktValLink">format-<wbr></wbr>id</span></span></a></td></tr><tr><td><span class="tocsublinknumber">4.1.4<tt> </tt></span><a href="#%28part._.Another_example%29" class="tocsubseclink" data-pltdoc="x">Another example</a></td></tr><tr><td><span class="tocsublinknumber">4.2<tt> </tt></span><a href="#%28part._.Making_our_own_struct%29" class="tocsubseclink" data-pltdoc="x">Making our own <span class="RktSym"><span class="RktStxLink">struct</span></span></a></td></tr><tr><td><span class="tocsublinknumber">4.3<tt> </tt></span><a href="#%28part._hash..refs%29" class="tocsubseclink" data-pltdoc="x">Using dot notation for nested hash lookups</a></td></tr><tr><td><span class="tocsublinknumber">5<tt> </tt></span><a href="#%28part._.Syntax_parameters%29" class="tocsubseclink" data-pltdoc="x">Syntax parameters</a></td></tr><tr><td><span class="tocsublinknumber">6<tt> </tt></span><a href="#%28part._.What_s_the_point_of_splicing-let_%29" class="tocsubseclink" data-pltdoc="x">What’s the point of <span class="RktSym"><span class="RktStxLink">splicing-<wbr></wbr>let</span></span>?</a></td></tr><tr><td><span class="tocsublinknumber">7<tt> </tt></span><a href="#%28part._.Robust_macros__syntax-parse%29" class="tocsubseclink" data-pltdoc="x">Robust macros:<span class="mywbr"> </span> syntax-<wbr></wbr>parse</a></td></tr><tr><td><span class="tocsublinknumber">7.1<tt> </tt></span><a href="#%28part._.Error-handling_strategies_for_functions%29" class="tocsubseclink" data-pltdoc="x">Error-<wbr></wbr>handling strategies for functions</a></td></tr><tr><td><span class="tocsublinknumber">7.2<tt> </tt></span><a href="#%28part._.Error-handling_strategies_for_macros%29" class="tocsubseclink" data-pltdoc="x">Error-<wbr></wbr>handling strategies for macros</a></td></tr><tr><td><span class="tocsublinknumber">7.3<tt> </tt></span><a href="#%28part._.Using_syntax-parse%29" class="tocsubseclink" data-pltdoc="x">Using <span class="RktSym"><span class="RktStxLink">syntax-<wbr></wbr>parse</span></span></a></td></tr><tr><td><span class="tocsublinknumber">8<tt> </tt></span><a href="#%28part._.References_and_.Acknowledgments%29" class="tocsubseclink" data-pltdoc="x">References and Acknowledgments</a></td></tr><tr><td><span class="tocsublinknumber">9<tt> </tt></span><a href="#%28part._.Epilogue%29" class="tocsubseclink" data-pltdoc="x">Epilogue</a></td></tr></table></div></div><div class="maincolumn"><div class="main"><h2><a name="(part._.Fear_of_.Macros)"></a>Fear of Macros</h2><div class="SAuthorListBox"><span class="SAuthorList"><p class="author"><a href="http://www.greghendershott.com">Greg Hendershott</a></p></span></div><p><div class="SIntrapara"></div><div class="SIntrapara"><img src="fear-of-macros.jpg" alt=""/>
-</div><div class="SIntrapara"><span class="Smaller">Copyright (c) 2012-2013 by Greg Hendershott. All rights reserved.</span></div><div class="SIntrapara"><span class="Smaller">Last updated 2014-03-25T08:32:00</span></div><div class="SIntrapara">Feedback and corrections are <a href="https://github.com/greghendershott/fear-of-macros/issues">welcome here</a>.</div></p><p>Contents:</p><table cellspacing="0"><tr><td><p><span class="hspace"> </span><a href="#%28part._.Preface%29" class="toptoclink" data-pltdoc="x">1<span class="hspace"> </span>Preface</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Our_plan_of_attack%29" class="toptoclink" data-pltdoc="x">2<span class="hspace"> </span>Our plan of attack</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Transform_%29" class="toptoclink" data-pltdoc="x">3<span class="hspace"> </span>Transform!</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.What_is_a_syntax_transformer_%29" class="toclink" data-pltdoc="x">3.1<span class="hspace"> </span>What is a syntax transformer?</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.What_s_the_input_%29" class="toclink" data-pltdoc="x">3.2<span class="hspace"> </span>What’s the input?</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Actually_transforming_the_input%29" class="toclink" data-pltdoc="x">3.3<span class="hspace"> </span>Actually transforming the input</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Compile_time_vs__run_time%29" class="toclink" data-pltdoc="x">3.4<span class="hspace"> </span>Compile time vs. run time</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._begin-for-syntax%29" class="toclink" data-pltdoc="x">3.5<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">begin-for-syntax</span></span></a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._pattern-matching%29" class="toptoclink" data-pltdoc="x">4<span class="hspace"> </span>Pattern matching: syntax-case and syntax-rules</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Pattern_variable_vs__template---fight_%29" class="toclink" data-pltdoc="x">4.1<span class="hspace"> </span>Pattern variable vs. template—<wbr></wbr>fight!</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._with-syntax%29" class="toclink" data-pltdoc="x">4.1.1<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">with-syntax</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._with-syntax_%29" class="toclink" data-pltdoc="x">4.1.2<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">with-syntax*</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._format-id%29" class="toclink" data-pltdoc="x">4.1.3<span class="hspace"> </span><span class="RktSym"><span class="RktValLink">format-id</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Another_example%29" class="toclink" data-pltdoc="x">4.1.4<span class="hspace"> </span>Another example</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Making_our_own_struct%29" class="toclink" data-pltdoc="x">4.2<span class="hspace"> </span>Making our own <span class="RktSym"><span class="RktStxLink">struct</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._hash..refs%29" class="toclink" data-pltdoc="x">4.3<span class="hspace"> </span>Using dot notation for nested hash lookups</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Syntax_parameters%29" class="toptoclink" data-pltdoc="x">5<span class="hspace"> </span>Syntax parameters</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.What_s_the_point_of_splicing-let_%29" class="toptoclink" data-pltdoc="x">6<span class="hspace"> </span>What’s the point of <span class="RktSym"><span class="RktStxLink">splicing-let</span></span>?</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Robust_macros__syntax-parse%29" class="toptoclink" data-pltdoc="x">7<span class="hspace"> </span>Robust macros: syntax-parse</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Error-handling_strategies_for_functions%29" class="toclink" data-pltdoc="x">7.1<span class="hspace"> </span>Error-handling strategies for functions</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Error-handling_strategies_for_macros%29" class="toclink" data-pltdoc="x">7.2<span class="hspace"> </span>Error-handling strategies for macros</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Using_syntax-parse%29" class="toclink" data-pltdoc="x">7.3<span class="hspace"> </span>Using <span class="RktSym"><span class="RktStxLink">syntax-parse</span></span></a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.References_and_.Acknowledgments%29" class="toptoclink" data-pltdoc="x">8<span class="hspace"> </span>References and Acknowledgments</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Epilogue%29" class="toptoclink" data-pltdoc="x">9<span class="hspace"> </span>Epilogue</a></p></td></tr></table><h3>1<tt> </tt><a name="(part._.Preface)"></a>Preface</h3><p>I learned Racket after 25 years of mostly using C and C++.</p><p>Some psychic whiplash resulted.</p><p>"All the parentheses" was actually not a big deal. Instead, the first
+</div><div class="SIntrapara"><span class="Smaller">Copyright (c) 2012-2014 by Greg Hendershott. All rights reserved.</span></div><div class="SIntrapara"><span class="Smaller">Last updated 2014-03-25T08:52:41</span></div><div class="SIntrapara">Feedback and corrections are <a href="https://github.com/greghendershott/fear-of-macros/issues">welcome here</a>.</div></p><p>Contents:</p><table cellspacing="0"><tr><td><p><span class="hspace"> </span><a href="#%28part._.Preface%29" class="toptoclink" data-pltdoc="x">1<span class="hspace"> </span>Preface</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Our_plan_of_attack%29" class="toptoclink" data-pltdoc="x">2<span class="hspace"> </span>Our plan of attack</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Transform_%29" class="toptoclink" data-pltdoc="x">3<span class="hspace"> </span>Transform!</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.What_is_a_syntax_transformer_%29" class="toclink" data-pltdoc="x">3.1<span class="hspace"> </span>What is a syntax transformer?</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.What_s_the_input_%29" class="toclink" data-pltdoc="x">3.2<span class="hspace"> </span>What’s the input?</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Actually_transforming_the_input%29" class="toclink" data-pltdoc="x">3.3<span class="hspace"> </span>Actually transforming the input</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Compile_time_vs__run_time%29" class="toclink" data-pltdoc="x">3.4<span class="hspace"> </span>Compile time vs. run time</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._begin-for-syntax%29" class="toclink" data-pltdoc="x">3.5<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">begin-for-syntax</span></span></a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._pattern-matching%29" class="toptoclink" data-pltdoc="x">4<span class="hspace"> </span>Pattern matching: syntax-case and syntax-rules</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Pattern_variable_vs__template---fight_%29" class="toclink" data-pltdoc="x">4.1<span class="hspace"> </span>Pattern variable vs. template—<wbr></wbr>fight!</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._with-syntax%29" class="toclink" data-pltdoc="x">4.1.1<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">with-syntax</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._with-syntax_%29" class="toclink" data-pltdoc="x">4.1.2<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">with-syntax*</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._format-id%29" class="toclink" data-pltdoc="x">4.1.3<span class="hspace"> </span><span class="RktSym"><span class="RktValLink">format-id</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Another_example%29" class="toclink" data-pltdoc="x">4.1.4<span class="hspace"> </span>Another example</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Making_our_own_struct%29" class="toclink" data-pltdoc="x">4.2<span class="hspace"> </span>Making our own <span class="RktSym"><span class="RktStxLink">struct</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._hash..refs%29" class="toclink" data-pltdoc="x">4.3<span class="hspace"> </span>Using dot notation for nested hash lookups</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Syntax_parameters%29" class="toptoclink" data-pltdoc="x">5<span class="hspace"> </span>Syntax parameters</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.What_s_the_point_of_splicing-let_%29" class="toptoclink" data-pltdoc="x">6<span class="hspace"> </span>What’s the point of <span class="RktSym"><span class="RktStxLink">splicing-let</span></span>?</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Robust_macros__syntax-parse%29" class="toptoclink" data-pltdoc="x">7<span class="hspace"> </span>Robust macros: syntax-parse</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Error-handling_strategies_for_functions%29" class="toclink" data-pltdoc="x">7.1<span class="hspace"> </span>Error-handling strategies for functions</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Error-handling_strategies_for_macros%29" class="toclink" data-pltdoc="x">7.2<span class="hspace"> </span>Error-handling strategies for macros</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Using_syntax-parse%29" class="toclink" data-pltdoc="x">7.3<span class="hspace"> </span>Using <span class="RktSym"><span class="RktStxLink">syntax-parse</span></span></a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.References_and_.Acknowledgments%29" class="toptoclink" data-pltdoc="x">8<span class="hspace"> </span>References and Acknowledgments</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="#%28part._.Epilogue%29" class="toptoclink" data-pltdoc="x">9<span class="hspace"> </span>Epilogue</a></p></td></tr></table><h3>1<tt> </tt><a name="(part._.Preface)"></a>Preface</h3><p>I learned Racket after 25 years of mostly using C and C++.</p><p>Some psychic whiplash resulted.</p><p>"All the parentheses" was actually not a big deal. Instead, the first
mind warp was functional programming. Before long I wrapped my brain
around it, and went on to become comfortable and effective with many
other aspects and features of Racket.</p><p>But two final frontiers remained: Macros and continuations.</p><p>I found that simple macros were easy and understandable, plus there
@@ -302,8 +302,7 @@ message from <span class="RktSym"><a href="http://docs.racket-lang.org/reference
could probably guess what’s happening, but in most cases they won’t.</p><p>2. Write some error handling code.</p><blockquote class="SCodeFlow"><table cellspacing="0" class="RktBlk"><tr><td><table cellspacing="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define%29%29" class="RktStxLink" data-pltdoc="x">define</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktSym">s</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/when_unless.html#%28form._%28%28lib._racket%2Fprivate%2Fletstx-scheme..rkt%29._unless%29%29" class="RktStxLink" data-pltdoc="x">unless</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string~3f%29%29" class="RktValLink" data-pltdoc="x">string?</a></span><span class="hspace"> </span><span class="RktSym">s</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/exns.html#%28def._%28%28quote._~23~25kernel%29._error%29%29" class="RktValLink" data-pltdoc="x">error</a></span><span class="hspace"> </span><span class="RktVal">'</span><span class="RktVal">misuse</span><span class="hspace"> </span><span class="RktVal">"expected a string, but got ~a"</span><span class="hspace"> </span><span class="RktSym">s</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string-append%29%29" class="RktValLink" data-pltdoc="x">string-append</a></span><span class="hspace"> </span><span class="RktSym">s</span><span class="hspace"> </span><span class="RktVal">" snazzy suffix"</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">User of the function:</span></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktVal">0</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktErr">misuse: expected a string, but got 0</span></p></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">I goofed, and understand why! It</span><span class="RktCmt">'</span><span class="RktCmt">s a shame the writer of the</span></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">function had to work so hard to tell me.</span></td></tr></table></blockquote><p>Unfortunately the error code tends to overwhelm and/or obscure our
function definition. Also, the error message is good but not
great. Improving it would require even more error code.</p><p>3. Use a contract.</p><blockquote class="SCodeFlow"><table cellspacing="0" class="RktBlk"><tr><td><table cellspacing="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/attaching-contracts-to-values.html#%28form._%28%28lib._racket%2Fcontract%2Fregion..rkt%29._define%2Fcontract%29%29" class="RktStxLink" data-pltdoc="x">define/contract</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktSym">s</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string~3f%29%29" class="RktValLink" data-pltdoc="x">string?</a></span><span class="hspace"> </span><span class="RktPn">. </span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/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="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string~3f%29%29" class="RktValLink" data-pltdoc="x">string?</a></span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string-append%29%29" class="RktValLink" data-pltdoc="x">string-append</a></span><span class="hspace"> </span><span class="RktSym">s</span><span class="hspace"> </span><span class="RktVal">" snazzy suffix"</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">User of the function:</span></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktVal">0</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktErr">misuse: contract violation</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">expected: string?</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">given: 0</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">in: the 1st argument of</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">(-> string? string?)</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">contract from: (function misuse)</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">blaming: program</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">at: eval:131.0</span></p></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">I goofed, and understand why! I</span><span class="RktCmt">'</span><span class="RktCmt">m happier, and I hear the writer of</span></td></tr><tr><td><span class="RktCmt">;</span><span class="RktCmt"> </span><span class="RktCmt">the function is happier, too.</span></td></tr></table></blockquote><p>This is the best of both worlds.</p><p>The contract is a simple and concise. Even better, it’s
-declarative. We say what we want, without needing to spell out what to
-do.</p><p>On the other hand the user of our function gets a very detailed error
+declarative. We say what we want to happen, not how.</p><p>On the other hand the user of our function gets a very detailed error
message. Plus, the message is in a standard, familiar format.</p><p>4. Use Typed Racket.</p><p><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" class="RktBlk"><tr><td><span class="RktMeta">#lang</span><span class="hspace"> </span><span class="RktMeta"></span><a href="http://docs.racket-lang.org/ts-reference/index.html" class="RktModLink" data-pltdoc="x"><span class="RktSym">typed/racket</span></a><span class="RktMeta"></span></td></tr></table></blockquote></div><div class="SIntrapara"><blockquote class="SCodeFlow"><table cellspacing="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">:</span><span class="hspace"> </span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">String</span><span class="hspace"> </span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/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">String</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr><tr><td><table cellspacing="0" class="RktBlk"><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/define.html#%28form._%28%28lib._racket%2Fprivate%2Fbase..rkt%29._define%29%29" class="RktStxLink" data-pltdoc="x">define</a></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktSym">s</span><span class="RktPn">)</span></td></tr><tr><td><span class="RktPlain"><span class="hspace"> </span></span><span class="hspace"> </span><span class="RktPn">(</span><span class="RktSym"><a href="http://docs.racket-lang.org/reference/strings.html#%28def._%28%28quote._~23~25kernel%29._string-append%29%29" class="RktValLink" data-pltdoc="x">string-append</a></span><span class="hspace"> </span><span class="RktSym">s</span><span class="hspace"> </span><span class="RktVal">" snazzy suffix"</span><span class="RktPn">)</span><span class="RktPn">)</span></td></tr></table></td></tr><tr><td><span class="stt">> </span><span class="RktPn">(</span><span class="RktSym">misuse</span><span class="hspace"> </span><span class="RktVal">0</span><span class="RktPn">)</span></td></tr><tr><td><p><span class="RktErr">eval:3:0: Type Checker: Expected String, but got Zero</span></p></td></tr><tr><td><p><span class="RktErr"></span><span class="hspace"> </span><span class="RktErr">in: 0</span></p></td></tr></table></blockquote></div></p><p>Even better, Typed Racket can catch usage mistakes up-front at compile
time.</p><h4>7.2<tt> </tt><a name="(part._.Error-handling_strategies_for_macros)"></a>Error-handling strategies for macros</h4><p>For macros, we have similar choices.</p><p>1. Ignore the possibility of misuse. This choice is even worse for
macros. The default error messages are even less likely to make sense,
@@ -323,8 +322,8 @@ confused.</p><blockquote class="SCodeFlow"><table cellspacing="0" class="RktBlk"
with many simple examples, followed by an
<a href="http://docs.racket-lang.org/syntax/stxparse-examples.html">Examples</a>
section illustrating many real-world scenarios.</p><p>Furthermore, everything I’d learned up to this point prepared me to
-appreciate what <span class="RktSym"><a href="http://docs.racket-lang.org/syntax/Parsing_Syntax.html#%28form._%28%28lib._syntax%2Fparse..rkt%29._syntax-parse%29%29" class="RktStxLink" data-pltdoc="x">syntax-parse</a></span> does, and why. That leaves
-the "how" of using it, which seems pretty straightforward, so far.</p><p>This might well be a temporary state of me "not knowing what I don’t
+appreciate what <span class="RktSym"><a href="http://docs.racket-lang.org/syntax/Parsing_Syntax.html#%28form._%28%28lib._syntax%2Fparse..rkt%29._syntax-parse%29%29" class="RktStxLink" data-pltdoc="x">syntax-parse</a></span> does, and why. The details of
+how to use it seem pretty straightforward, so far.</p><p>This might well be a temporary state of me "not knowing what I don’t
know". As I dig in and use it more, maybe I’ll discover something
confusing or tricky. If/when I do, I’ll come back here and update
this.</p><p>But for now I’ll focus on improving the previous parts.</p><h3>8<tt> </tt><a name="(part._.References_and_.Acknowledgments)"></a>References and Acknowledgments</h3><p>Eli Barzliay’s blog post,
diff --git a/index.html b/index.html
@@ -1,3 +1,3 @@
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"/><title>Fear of Macros</title><link rel="stylesheet" type="text/css" href="scribble.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="gh.css" title="default"/><script type="text/javascript" src="scribble-common.js"></script><!--[if IE 6]><style type="text/css">.SIEHidden { overflow: hidden; }</style><![endif]--><meta name="keywords" content="Racket,macros,Scheme"><meta name="description" content="Practical Racket macros"><meta name="author" content="Greg Hendershott"><meta name="charset" content="utf-8"><link href='http://fonts.googleapis.com/css?family=Fenix' rel='stylesheet' type='text/css'><script type="text/javascript">var _gaq = _gaq || [];_gaq.push(['_setAccount', 'UA-29709446-1']);_gaq.push(['_setDomainName', 'greghendershott.com']);_gaq.push(['_trackPageview']);(function() {var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);})();</script></head><body id="scribble-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="" class="tocviewselflink" data-pltdoc="x">Fear of Macros</a></td></tr></table></div><div class="tocviewsublistonly" style="display: block;" id="tocview_0"><table cellspacing="0" cellpadding="0"><tr><td align="right">1 </td><td><a href="Preface.html" class="tocviewlink" data-pltdoc="x">Preface</a></td></tr><tr><td align="right">2 </td><td><a href="Our_plan_of_attack.html" class="tocviewlink" data-pltdoc="x">Our plan of attack</a></td></tr><tr><td align="right">3 </td><td><a href="Transform_.html" class="tocviewlink" data-pltdoc="x">Transform!</a></td></tr><tr><td align="right">4 </td><td><a href="pattern-matching.html" class="tocviewlink" data-pltdoc="x">Pattern matching:<span class="mywbr"> </span> syntax-<wbr></wbr>case and syntax-<wbr></wbr>rules</a></td></tr><tr><td align="right">5 </td><td><a href="Syntax_parameters.html" class="tocviewlink" data-pltdoc="x">Syntax parameters</a></td></tr><tr><td align="right">6 </td><td><a href="What_s_the_point_of_splicing-let_.html" class="tocviewlink" data-pltdoc="x">What’s the point of <span class="RktSym"><span class="RktStxLink">splicing-<wbr></wbr>let</span></span>?</a></td></tr><tr><td align="right">7 </td><td><a href="Robust_macros__syntax-parse.html" class="tocviewlink" data-pltdoc="x">Robust macros:<span class="mywbr"> </span> syntax-<wbr></wbr>parse</a></td></tr><tr><td align="right">8 </td><td><a href="References_and_Acknowledgments.html" class="tocviewlink" data-pltdoc="x">References and Acknowledgments</a></td></tr><tr><td align="right">9 </td><td><a href="Epilogue.html" class="tocviewlink" data-pltdoc="x">Epilogue</a></td></tr></table></div></div></div><div class="tocsub"><div class="tocsubtitle">On this page:</div><table class="tocsublist" cellspacing="0"><tr><td><span class="tocsublinknumber"></span><a href="#%28part._.Fear_of_.Macros%29" class="tocsubseclink" data-pltdoc="x">Fear of Macros</a></td></tr></table></div></div><div class="maincolumn"><div class="main"><div class="navsettop"><span class="navleft"> </span><span class="navright"> <span class="nonavigation">← prev</span> <span class="nonavigation">up</span> <a href="Preface.html" title="forward to "1 Preface"" data-pltdoc="x">next →</a></span> </div><h2><a name="(part._.Fear_of_.Macros)"></a>Fear of Macros</h2><div class="SAuthorListBox"><span class="SAuthorList"><p class="author"><a href="http://www.greghendershott.com">Greg Hendershott</a></p></span></div><p><div class="SIntrapara"></div><div class="SIntrapara"><img src="fear-of-macros.jpg" alt=""/>
-</div><div class="SIntrapara"><span class="Smaller">Copyright (c) 2012-2013 by Greg Hendershott. All rights reserved.</span></div><div class="SIntrapara"><span class="Smaller">Last updated 2014-03-25T08:31:51</span></div><div class="SIntrapara">Feedback and corrections are <a href="https://github.com/greghendershott/fear-of-macros/issues">welcome here</a>.</div></p><p>Contents:</p><table cellspacing="0"><tr><td><p><span class="hspace"> </span><a href="Preface.html" class="toptoclink" data-pltdoc="x">1<span class="hspace"> </span>Preface</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Our_plan_of_attack.html" class="toptoclink" data-pltdoc="x">2<span class="hspace"> </span>Our plan of attack</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html" class="toptoclink" data-pltdoc="x">3<span class="hspace"> </span>Transform!</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html#%28part._.What_is_a_syntax_transformer_%29" class="toclink" data-pltdoc="x">3.1<span class="hspace"> </span>What is a syntax transformer?</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html#%28part._.What_s_the_input_%29" class="toclink" data-pltdoc="x">3.2<span class="hspace"> </span>What’s the input?</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html#%28part._.Actually_transforming_the_input%29" class="toclink" data-pltdoc="x">3.3<span class="hspace"> </span>Actually transforming the input</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html#%28part._.Compile_time_vs__run_time%29" class="toclink" data-pltdoc="x">3.4<span class="hspace"> </span>Compile time vs. run time</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html#%28part._begin-for-syntax%29" class="toclink" data-pltdoc="x">3.5<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">begin-for-syntax</span></span></a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html" class="toptoclink" data-pltdoc="x">4<span class="hspace"> </span>Pattern matching: syntax-case and syntax-rules</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._.Pattern_variable_vs__template---fight_%29" class="toclink" data-pltdoc="x">4.1<span class="hspace"> </span>Pattern variable vs. template—<wbr></wbr>fight!</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._with-syntax%29" class="toclink" data-pltdoc="x">4.1.1<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">with-syntax</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._with-syntax_%29" class="toclink" data-pltdoc="x">4.1.2<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">with-syntax*</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._format-id%29" class="toclink" data-pltdoc="x">4.1.3<span class="hspace"> </span><span class="RktSym"><span class="RktValLink">format-id</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._.Another_example%29" class="toclink" data-pltdoc="x">4.1.4<span class="hspace"> </span>Another example</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._.Making_our_own_struct%29" class="toclink" data-pltdoc="x">4.2<span class="hspace"> </span>Making our own <span class="RktSym"><span class="RktStxLink">struct</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._hash..refs%29" class="toclink" data-pltdoc="x">4.3<span class="hspace"> </span>Using dot notation for nested hash lookups</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Syntax_parameters.html" class="toptoclink" data-pltdoc="x">5<span class="hspace"> </span>Syntax parameters</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="What_s_the_point_of_splicing-let_.html" class="toptoclink" data-pltdoc="x">6<span class="hspace"> </span>What’s the point of <span class="RktSym"><span class="RktStxLink">splicing-let</span></span>?</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Robust_macros__syntax-parse.html" class="toptoclink" data-pltdoc="x">7<span class="hspace"> </span>Robust macros: syntax-parse</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Robust_macros__syntax-parse.html#%28part._.Error-handling_strategies_for_functions%29" class="toclink" data-pltdoc="x">7.1<span class="hspace"> </span>Error-handling strategies for functions</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Robust_macros__syntax-parse.html#%28part._.Error-handling_strategies_for_macros%29" class="toclink" data-pltdoc="x">7.2<span class="hspace"> </span>Error-handling strategies for macros</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Robust_macros__syntax-parse.html#%28part._.Using_syntax-parse%29" class="toclink" data-pltdoc="x">7.3<span class="hspace"> </span>Using <span class="RktSym"><span class="RktStxLink">syntax-parse</span></span></a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="References_and_Acknowledgments.html" class="toptoclink" data-pltdoc="x">8<span class="hspace"> </span>References and Acknowledgments</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Epilogue.html" class="toptoclink" data-pltdoc="x">9<span class="hspace"> </span>Epilogue</a></p></td></tr></table><div class="navsetbottom"><span class="navleft"> </span><span class="navright"> <span class="nonavigation">← prev</span> <span class="nonavigation">up</span> <a href="Preface.html" title="forward to "1 Preface"" data-pltdoc="x">next →</a></span> </div></div></div><div id="contextindicator"> </div></body></html>
-\ No newline at end of file
+</div><div class="SIntrapara"><span class="Smaller">Copyright (c) 2012-2014 by Greg Hendershott. All rights reserved.</span></div><div class="SIntrapara"><span class="Smaller">Last updated 2014-03-25T08:52:33</span></div><div class="SIntrapara">Feedback and corrections are <a href="https://github.com/greghendershott/fear-of-macros/issues">welcome here</a>.</div></p><p>Contents:</p><table cellspacing="0"><tr><td><p><span class="hspace"> </span><a href="Preface.html" class="toptoclink" data-pltdoc="x">1<span class="hspace"> </span>Preface</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Our_plan_of_attack.html" class="toptoclink" data-pltdoc="x">2<span class="hspace"> </span>Our plan of attack</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html" class="toptoclink" data-pltdoc="x">3<span class="hspace"> </span>Transform!</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html#%28part._.What_is_a_syntax_transformer_%29" class="toclink" data-pltdoc="x">3.1<span class="hspace"> </span>What is a syntax transformer?</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html#%28part._.What_s_the_input_%29" class="toclink" data-pltdoc="x">3.2<span class="hspace"> </span>What’s the input?</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html#%28part._.Actually_transforming_the_input%29" class="toclink" data-pltdoc="x">3.3<span class="hspace"> </span>Actually transforming the input</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html#%28part._.Compile_time_vs__run_time%29" class="toclink" data-pltdoc="x">3.4<span class="hspace"> </span>Compile time vs. run time</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Transform_.html#%28part._begin-for-syntax%29" class="toclink" data-pltdoc="x">3.5<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">begin-for-syntax</span></span></a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html" class="toptoclink" data-pltdoc="x">4<span class="hspace"> </span>Pattern matching: syntax-case and syntax-rules</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._.Pattern_variable_vs__template---fight_%29" class="toclink" data-pltdoc="x">4.1<span class="hspace"> </span>Pattern variable vs. template—<wbr></wbr>fight!</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._with-syntax%29" class="toclink" data-pltdoc="x">4.1.1<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">with-syntax</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._with-syntax_%29" class="toclink" data-pltdoc="x">4.1.2<span class="hspace"> </span><span class="RktSym"><span class="RktStxLink">with-syntax*</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._format-id%29" class="toclink" data-pltdoc="x">4.1.3<span class="hspace"> </span><span class="RktSym"><span class="RktValLink">format-id</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._.Another_example%29" class="toclink" data-pltdoc="x">4.1.4<span class="hspace"> </span>Another example</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._.Making_our_own_struct%29" class="toclink" data-pltdoc="x">4.2<span class="hspace"> </span>Making our own <span class="RktSym"><span class="RktStxLink">struct</span></span></a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="pattern-matching.html#%28part._hash..refs%29" class="toclink" data-pltdoc="x">4.3<span class="hspace"> </span>Using dot notation for nested hash lookups</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Syntax_parameters.html" class="toptoclink" data-pltdoc="x">5<span class="hspace"> </span>Syntax parameters</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="What_s_the_point_of_splicing-let_.html" class="toptoclink" data-pltdoc="x">6<span class="hspace"> </span>What’s the point of <span class="RktSym"><span class="RktStxLink">splicing-let</span></span>?</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Robust_macros__syntax-parse.html" class="toptoclink" data-pltdoc="x">7<span class="hspace"> </span>Robust macros: syntax-parse</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Robust_macros__syntax-parse.html#%28part._.Error-handling_strategies_for_functions%29" class="toclink" data-pltdoc="x">7.1<span class="hspace"> </span>Error-handling strategies for functions</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Robust_macros__syntax-parse.html#%28part._.Error-handling_strategies_for_macros%29" class="toclink" data-pltdoc="x">7.2<span class="hspace"> </span>Error-handling strategies for macros</a></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Robust_macros__syntax-parse.html#%28part._.Using_syntax-parse%29" class="toclink" data-pltdoc="x">7.3<span class="hspace"> </span>Using <span class="RktSym"><span class="RktStxLink">syntax-parse</span></span></a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="References_and_Acknowledgments.html" class="toptoclink" data-pltdoc="x">8<span class="hspace"> </span>References and Acknowledgments</a></p></td></tr><tr><td><p><span class="hspace"></span></p></td></tr><tr><td><p><span class="hspace"> </span><a href="Epilogue.html" class="toptoclink" data-pltdoc="x">9<span class="hspace"> </span>Epilogue</a></p></td></tr></table><div class="navsetbottom"><span class="navleft"> </span><span class="navright"> <span class="nonavigation">← prev</span> <span class="nonavigation">up</span> <a href="Preface.html" title="forward to "1 Preface"" data-pltdoc="x">next →</a></span> </div></div></div><div id="contextindicator"> </div></body></html>
+\ No newline at end of file
