<html><head><metahttp-equiv="content-type"content="text/html; charset=utf-8"/><title>6 Second tutorial</title><linkrel="stylesheet"type="text/css"href="scribble.css"title="default"/><linkrel="stylesheet"type="text/css"href="racket.css"title="default"/><linkrel="stylesheet"type="text/css"href="manual-style.css"title="default"/><linkrel="stylesheet"type="text/css"href="manual-racket.css"title="default"/><linkrel="stylesheet"type="text/css"href="mb.scss"title="default"/><scripttype="text/javascript"src="scribble-common.js"></script><scripttype="text/javascript"src="manual-racket.js"></script><!--[if IE 6]><style type="text/css">.SIEHidden { overflow: hidden; }</style><![endif]--></head><bodyid="scribble-racket-lang-org"><divclass="tocset"><divclass="tocview"><divclass="tocviewlist tocviewlisttopspace"><divclass="tocviewtitle"><tablecellspacing="0"cellpadding="0"><tr><tdstyle="width: 1em;"><ahref="javascript:void(0);"title="Expand/Collapse"class="tocviewtoggle"onclick="TocviewToggle(this,"tocview_0");">▼</a></td><td></td><td><ahref="index.html"class="tocviewlink"data-pltdoc="x">Pollen:<spanclass="mywbr"> </span> the book is a program</a></td></tr></table></div><divclass="tocviewsublisttop"style="display: block;"id="tocview_0"><tablecellspacing="0"cellpadding="0"><tr><tdalign="right">1 </td><td><ahref="Installation.html"class="tocviewlink"data-pltdoc="x">Installation</a></td></tr><tr><tdalign="right">2 </td><td><ahref="quick-tour.html"class="tocviewlink"data-pltdoc="x">Quick tour</a></td></tr><tr><tdalign="right">3 </td><td><ahref="Backstory.html"class="tocviewlink"data-pltdoc="x">Backstory</a></td></tr><tr><tdalign="right">4 </td><td><ahref="big-picture.html"class="tocviewlink"data-pltdoc="x">The big picture</a></td></tr><tr><tdalign="right">5 </td><td><ahref="first-tutorial.html"class="tocviewlink"data-pltdoc="x">First tutorial</a></td></tr><tr><tdalign="right">6 </td><td><ahref="second-tutorial.html"class="tocviewselflink"data-pltdoc="x">Second tutorial</a></td></tr><tr><tdalign="right">7 </td><td><ahref="third-tutorial.html"class="tocviewlink"data-pltdoc="x">Third tutorial</a></td></tr><tr><tdalign="right">8 </td><td><ahref="raco-pollen.html"class="tocviewlink"data-pltdoc="x">Using <spanclass="stt">raco pollen</span></a></td></tr><tr><tdalign="right">9 </td><td><ahref="File_formats.html"class="tocviewlink"data-pltdoc="x">File formats</a></td></tr><tr><tdalign="right">10 </td><td><ahref="reader.html"class="tocviewlink"data-pltdoc="x">◊ command overview</a></td></tr><tr><tdalign="right">11 </td><td><ahref="Module_reference.html"class="tocviewlink"data-pltdoc="x">Module reference</a></td></tr><tr><tdalign="right">12 </td><td><ahref="Acknowledgments.html"class="tocviewlink"data-pltdoc="x">Acknowledgments</a></td></tr><tr><tdalign="right">13 </td><td><ahref="License___source_code.html"class="tocviewlink"data-pltdoc="x">License & source code</a></td></tr><tr><tdalign="right"></td><td><ahref="doc-index.html"class="tocviewlink"data-pltdoc="x">Index</a></td></tr></table></div></div><divclass="tocviewlist"><tablecellspacing="0"cellpadding="0"><tr><tdstyle="width: 1em;"><ahref="javascript:void(0);"title="Expand/Collapse"class="tocviewtoggle"onclick="TocviewToggle(this,"tocview_1");">►</a></td><td>6 </td><td><ahref="second-tutorial.html"class="tocviewselflink"data-pltdoc="x">Second tutorial</a></td></tr></table><divclass="tocviewsublistbottom"style="display: none;"id="tocview_1"><tablecellspacing="0"cellpadding="0"><tr><tdalign="right">6.1 </td><td><ahref="second-tutorial.html#%28part._tutorial-2._.Prerequisites%29"class="tocviewlink"data-pltdoc="x">Prerequisites</a></td></tr><tr><tdalign="right">6.2 </td><td><ahref="second-tutorial.html#%28part._.Prelude__my_principled_objection_to_.Markdown%29"class="tocviewlink"data-pltdoc="x">Prelude:<spanclass="mywbr"> </span> my p
<br/>You’re getting the general idea, right? So let’s move on.</p><h4>6.5<tt> </tt><aname="(part._tutorial-2._.Intermission)"></a>Intermission</h4><p>If you only need one page for your article, you can stop here. You now know everything necessary to publish a single-page article using authoring mode. You know how to create the mandatory ingredients — a source file and a template — and you also know how to link to an optional CSS file, which can be dynamically generated.</p><p>If you want to create a multi-page article, however, you need to get through one more big idea. This might be a good time to take a break.</p><h4>6.6<tt> </tt><aname="(part._tutorial-2._.Pagetrees)"></a>Pagetrees</h4><p>A <spanstyle="font-style: italic">pagetree</span> is a hierarchical list of Pollen pages. When you have multiple pages in your project, the pagetree establishes relationships among those pages. At its most basic, a pagetree establishes a linear sequence for the pages. But pagetrees can also establish hierarchical relationships — for instance, a book-length project can be organized into chapters, the chapters into sections, and so on. The pagetree doesn’t impose any semantics on the organization of your project. It’s just a tree, and it’s up to you how many layers to establish, what those layers mean, and so on.</p><blockquoteclass="refpara"><blockquoteclass="refcolumn"><blockquoteclass="refcontent"><p><spanstyle="font-style: italic">Pagemap</span> might’ve been an equally good name, and perhaps more consistent with similar concepts in other web-publishing systems. But I avoided it out of deference to Racket’s <spanclass="RktSym"><ahref="http://docs.racket-lang.org/reference/pairs.html#%28def._%28%28lib._racket%2Fprivate%2Fmap..rkt%29._map%29%29"class="RktValLink"data-pltdoc="x">map</a></span> function, which means something completely different.</p></blockquote></blockquote></blockquote><h5>6.6.1<tt> </tt><aname="(part._tutorial-2._.Pagetree_navigation)"></a>Pagetree navigation</h5><p>Pagetrees are used in various ways throughout Pollen. But the most obvious use for a pagetree is to add navigational links to your pages. Obviously, in a multi-page article, readers need a way of getting from one page to the next. In this part of the tutorial, we’ll expand our sample article from one page to three, and see how to create “previous page” and “next page” links in our template that are dynamically generated relative to the current page.</p><h5>6.6.2<tt> </tt><aname="(part._tutorial-2._.Using_the_automatic_pagetree)"></a>Using the automatic pagetree</h5><p>You’ve actually already been exposed to pagetrees (though I didn’t tell you about it at the time). Recall that the dashboard of the project server is located at <spanclass="stt">http://localhost:8080/index.ptree</span>. The list of files you see in the dashboard is a pagetree that Pollen creates by reading the files in the current directory and arranging them in alphabetical order.</p><p>If the multiple pages in your project are already ordered by filename, then you can rely on this automatic pagetree.</p><p>From earlier in the tutorial, you have a Markdown source file called <spanclass="stt">article.html.pmd</span> that looks like this:</p><divclass="fileblock"><divclass="SIntrapara"><divclass="fileblock_filetitle"><spanclass="fileblock_filename"><spanclass="stt">"article.html.pmd"</span></span></div></div><divclass="SIntrapara"><divclass="fileblock_filecontent"><divclass="SIntrapara"><blockquoteclass="SCodeFlow"><tablecellspacing="0"cellpadding="0"class="RktBlk"><tr><td><spanclass="RktMeta">#lang</span><spanclass="hspace"> </span><spanclass="RktMeta"></span><ahref="index.html"class="RktModLink"data-pltdoc="x"><spanclass="RktSym">pollen</span></a><spanclass="RktMeta"></span></td></tr><tr><td><spanclass="RktMeta"> </span></td></tr><tr><td><spanclass="RktMeta">Deep</span><spanclass="hspace"> </span><spanclass="
