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| author | Waylan Limberg <waylan@dev.westell.com> | 2010-02-22 22:59:20 -0500 |
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| committer | Waylan Limberg <waylan@dev.westell.com> | 2010-02-22 22:59:20 -0500 |
| commit | b9458647a471561cf121edc03b2b8fd5aadff316 (patch) | |
| tree | 21810589a1197d8c14ad825ee202b11b979eaaad /tests/basic/markdown-syntax.html | |
| parent | b96331c66b8421d10f9e040758c82badf97191b1 (diff) | |
| parent | 3eb86a20f0b20e44b34087c16e20ff40cead7420 (diff) | |
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diff --git a/tests/basic/markdown-syntax.html b/tests/basic/markdown-syntax.html new file mode 100644 index 0000000..038c9d1 --- /dev/null +++ b/tests/basic/markdown-syntax.html @@ -0,0 +1,728 @@ +<h1>Markdown: Syntax</h1> +<ul id="ProjectSubmenu"> + <li><a href="/projects/markdown/" title="Markdown Project Page">Main</a></li> + <li><a href="/projects/markdown/basics" title="Markdown Basics">Basics</a></li> + <li><a class="selected" title="Markdown Syntax Documentation">Syntax</a></li> + <li><a href="/projects/markdown/license" title="Pricing and License Information">License</a></li> + <li><a href="/projects/markdown/dingus" title="Online Markdown Web Form">Dingus</a></li> +</ul> + +<ul> +<li><a href="#overview">Overview</a><ul> +<li><a href="#philosophy">Philosophy</a></li> +<li><a href="#html">Inline HTML</a></li> +<li><a href="#autoescape">Automatic Escaping for Special Characters</a></li> +</ul> +</li> +<li><a href="#block">Block Elements</a><ul> +<li><a href="#p">Paragraphs and Line Breaks</a></li> +<li><a href="#header">Headers</a></li> +<li><a href="#blockquote">Blockquotes</a></li> +<li><a href="#list">Lists</a></li> +<li><a href="#precode">Code Blocks</a></li> +<li><a href="#hr">Horizontal Rules</a></li> +</ul> +</li> +<li><a href="#span">Span Elements</a><ul> +<li><a href="#link">Links</a></li> +<li><a href="#em">Emphasis</a></li> +<li><a href="#code">Code</a></li> +<li><a href="#img">Images</a></li> +</ul> +</li> +<li><a href="#misc">Miscellaneous</a><ul> +<li><a href="#backslash">Backslash Escapes</a></li> +<li><a href="#autolink">Automatic Links</a></li> +</ul> +</li> +</ul> +<p><strong>Note:</strong> This document is itself written using Markdown; you +can <a href="/projects/markdown/syntax.text">see the source for it by adding '.text' to the URL</a>.</p> +<hr /> +<h2 id="overview">Overview</h2> + +<h3 id="philosophy">Philosophy</h3> + +<p>Markdown is intended to be as easy-to-read and easy-to-write as is feasible.</p> +<p>Readability, however, is emphasized above all else. A Markdown-formatted +document should be publishable as-is, as plain text, without looking +like it's been marked up with tags or formatting instructions. While +Markdown's syntax has been influenced by several existing text-to-HTML +filters -- including <a href="http://docutils.sourceforge.net/mirror/setext.html">Setext</a>, <a href="http://www.aaronsw.com/2002/atx/">atx</a>, <a href="http://textism.com/tools/textile/">Textile</a>, <a href="http://docutils.sourceforge.net/rst.html">reStructuredText</a>, +<a href="http://www.triptico.com/software/grutatxt.html">Grutatext</a>, and <a href="http://ettext.taint.org/doc/">EtText</a> -- the single biggest source of +inspiration for Markdown's syntax is the format of plain text email.</p> +<p>To this end, Markdown's syntax is comprised entirely of punctuation +characters, which punctuation characters have been carefully chosen so +as to look like what they mean. E.g., asterisks around a word actually +look like *emphasis*. Markdown lists look like, well, lists. Even +blockquotes look like quoted passages of text, assuming you've ever +used email.</p> +<h3 id="html">Inline HTML</h3> + +<p>Markdown's syntax is intended for one purpose: to be used as a +format for <em>writing</em> for the web.</p> +<p>Markdown is not a replacement for HTML, or even close to it. Its +syntax is very small, corresponding only to a very small subset of +HTML tags. The idea is <em>not</em> to create a syntax that makes it easier +to insert HTML tags. In my opinion, HTML tags are already easy to +insert. The idea for Markdown is to make it easy to read, write, and +edit prose. HTML is a <em>publishing</em> format; Markdown is a <em>writing</em> +format. Thus, Markdown's formatting syntax only addresses issues that +can be conveyed in plain text.</p> +<p>For any markup that is not covered by Markdown's syntax, you simply +use HTML itself. There's no need to preface it or delimit it to +indicate that you're switching from Markdown to HTML; you just use +the tags.</p> +<p>The only restrictions are that block-level HTML elements -- e.g. <code><div></code>, +<code><table></code>, <code><pre></code>, <code><p></code>, etc. -- must be separated from surrounding +content by blank lines, and the start and end tags of the block should +not be indented with tabs or spaces. Markdown is smart enough not +to add extra (unwanted) <code><p></code> tags around HTML block-level tags.</p> +<p>For example, to add an HTML table to a Markdown article:</p> +<pre><code>This is a regular paragraph. + +<table> + <tr> + <td>Foo</td> + </tr> +</table> + +This is another regular paragraph. +</code></pre> +<p>Note that Markdown formatting syntax is not processed within block-level +HTML tags. E.g., you can't use Markdown-style <code>*emphasis*</code> inside an +HTML block.</p> +<p>Span-level HTML tags -- e.g. <code><span></code>, <code><cite></code>, or <code><del></code> -- can be +used anywhere in a Markdown paragraph, list item, or header. If you +want, you can even use HTML tags instead of Markdown formatting; e.g. if +you'd prefer to use HTML <code><a></code> or <code><img></code> tags instead of Markdown's +link or image syntax, go right ahead.</p> +<p>Unlike block-level HTML tags, Markdown syntax <em>is</em> processed within +span-level tags.</p> +<h3 id="autoescape">Automatic Escaping for Special Characters</h3> + +<p>In HTML, there are two characters that demand special treatment: <code><</code> +and <code>&</code>. Left angle brackets are used to start tags; ampersands are +used to denote HTML entities. If you want to use them as literal +characters, you must escape them as entities, e.g. <code>&lt;</code>, and +<code>&amp;</code>.</p> +<p>Ampersands in particular are bedeviling for web writers. If you want to +write about 'AT&T', you need to write '<code>AT&amp;T</code>'. You even need to +escape ampersands within URLs. Thus, if you want to link to:</p> +<pre><code>http://images.google.com/images?num=30&q=larry+bird +</code></pre> +<p>you need to encode the URL as:</p> +<pre><code>http://images.google.com/images?num=30&amp;q=larry+bird +</code></pre> +<p>in your anchor tag <code>href</code> attribute. Needless to say, this is easy to +forget, and is probably the single most common source of HTML validation +errors in otherwise well-marked-up web sites.</p> +<p>Markdown allows you to use these characters naturally, taking care of +all the necessary escaping for you. If you use an ampersand as part of +an HTML entity, it remains unchanged; otherwise it will be translated +into <code>&amp;</code>.</p> +<p>So, if you want to include a copyright symbol in your article, you can write:</p> +<pre><code>&copy; +</code></pre> +<p>and Markdown will leave it alone. But if you write:</p> +<pre><code>AT&T +</code></pre> +<p>Markdown will translate it to:</p> +<pre><code>AT&amp;T +</code></pre> +<p>Similarly, because Markdown supports <a href="#html">inline HTML</a>, if you use +angle brackets as delimiters for HTML tags, Markdown will treat them as +such. But if you write:</p> +<pre><code>4 < 5 +</code></pre> +<p>Markdown will translate it to:</p> +<pre><code>4 &lt; 5 +</code></pre> +<p>However, inside Markdown code spans and blocks, angle brackets and +ampersands are <em>always</em> encoded automatically. This makes it easy to use +Markdown to write about HTML code. (As opposed to raw HTML, which is a +terrible format for writing about HTML syntax, because every single <code><</code> +and <code>&</code> in your example code needs to be escaped.)</p> +<hr /> +<h2 id="block">Block Elements</h2> + +<h3 id="p">Paragraphs and Line Breaks</h3> + +<p>A paragraph is simply one or more consecutive lines of text, separated +by one or more blank lines. (A blank line is any line that looks like a +blank line -- a line containing nothing but spaces or tabs is considered +blank.) Normal paragraphs should not be intended with spaces or tabs.</p> +<p>The implication of the "one or more consecutive lines of text" rule is +that Markdown supports "hard-wrapped" text paragraphs. This differs +significantly from most other text-to-HTML formatters (including Movable +Type's "Convert Line Breaks" option) which translate every line break +character in a paragraph into a <code><br /></code> tag.</p> +<p>When you <em>do</em> want to insert a <code><br /></code> break tag using Markdown, you +end a line with two or more spaces, then type return.</p> +<p>Yes, this takes a tad more effort to create a <code><br /></code>, but a simplistic +"every line break is a <code><br /></code>" rule wouldn't work for Markdown. +Markdown's email-style <a href="#blockquote">blockquoting</a> and multi-paragraph <a href="#list">list items</a> +work best -- and look better -- when you format them with hard breaks.</p> +<h3 id="header">Headers</h3> + +<p>Markdown supports two styles of headers, <a href="http://docutils.sourceforge.net/mirror/setext.html">Setext</a> and <a href="http://www.aaronsw.com/2002/atx/">atx</a>.</p> +<p>Setext-style headers are "underlined" using equal signs (for first-level +headers) and dashes (for second-level headers). For example:</p> +<pre><code>This is an H1 +============= + +This is an H2 +------------- +</code></pre> +<p>Any number of underlining <code>=</code>'s or <code>-</code>'s will work.</p> +<p>Atx-style headers use 1-6 hash characters at the start of the line, +corresponding to header levels 1-6. For example:</p> +<pre><code># This is an H1 + +## This is an H2 + +###### This is an H6 +</code></pre> +<p>Optionally, you may "close" atx-style headers. This is purely +cosmetic -- you can use this if you think it looks better. The +closing hashes don't even need to match the number of hashes +used to open the header. (The number of opening hashes +determines the header level.) :</p> +<pre><code># This is an H1 # + +## This is an H2 ## + +### This is an H3 ###### +</code></pre> +<h3 id="blockquote">Blockquotes</h3> + +<p>Markdown uses email-style <code>></code> characters for blockquoting. If you're +familiar with quoting passages of text in an email message, then you +know how to create a blockquote in Markdown. It looks best if you hard +wrap the text and put a <code>></code> before every line:</p> +<pre><code>> This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet, +> consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus. +> Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus. +> +> Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse +> id sem consectetuer libero luctus adipiscing. +</code></pre> +<p>Markdown allows you to be lazy and only put the <code>></code> before the first +line of a hard-wrapped paragraph:</p> +<pre><code>> This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet, +consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus. +Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus. + +> Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse +id sem consectetuer libero luctus adipiscing. +</code></pre> +<p>Blockquotes can be nested (i.e. a blockquote-in-a-blockquote) by +adding additional levels of <code>></code>:</p> +<pre><code>> This is the first level of quoting. +> +> > This is nested blockquote. +> +> Back to the first level. +</code></pre> +<p>Blockquotes can contain other Markdown elements, including headers, lists, +and code blocks:</p> +<pre><code>> ## This is a header. +> +> 1. This is the first list item. +> 2. This is the second list item. +> +> Here's some example code: +> +> return shell_exec("echo $input | $markdown_script"); +</code></pre> +<p>Any decent text editor should make email-style quoting easy. For +example, with BBEdit, you can make a selection and choose Increase +Quote Level from the Text menu.</p> +<h3 id="list">Lists</h3> + +<p>Markdown supports ordered (numbered) and unordered (bulleted) lists.</p> +<p>Unordered lists use asterisks, pluses, and hyphens -- interchangably +-- as list markers:</p> +<pre><code>* Red +* Green +* Blue +</code></pre> +<p>is equivalent to:</p> +<pre><code>+ Red ++ Green ++ Blue +</code></pre> +<p>and:</p> +<pre><code>- Red +- Green +- Blue +</code></pre> +<p>Ordered lists use numbers followed by periods:</p> +<pre><code>1. Bird +2. McHale +3. Parish +</code></pre> +<p>It's important to note that the actual numbers you use to mark the +list have no effect on the HTML output Markdown produces. The HTML +Markdown produces from the above list is:</p> +<pre><code><ol> +<li>Bird</li> +<li>McHale</li> +<li>Parish</li> +</ol> +</code></pre> +<p>If you instead wrote the list in Markdown like this:</p> +<pre><code>1. Bird +1. McHale +1. Parish +</code></pre> +<p>or even:</p> +<pre><code>3. Bird +1. McHale +8. Parish +</code></pre> +<p>you'd get the exact same HTML output. The point is, if you want to, +you can use ordinal numbers in your ordered Markdown lists, so that +the numbers in your source match the numbers in your published HTML. +But if you want to be lazy, you don't have to.</p> +<p>If you do use lazy list numbering, however, you should still start the +list with the number 1. At some point in the future, Markdown may support +starting ordered lists at an arbitrary number.</p> +<p>List markers typically start at the left margin, but may be indented by +up to three spaces. List markers must be followed by one or more spaces +or a tab.</p> +<p>To make lists look nice, you can wrap items with hanging indents:</p> +<pre><code>* Lorem ipsum dolor sit amet, consectetuer adipiscing elit. + Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi, + viverra nec, fringilla in, laoreet vitae, risus. +* Donec sit amet nisl. Aliquam semper ipsum sit amet velit. + Suspendisse id sem consectetuer libero luctus adipiscing. +</code></pre> +<p>But if you want to be lazy, you don't have to:</p> +<pre><code>* Lorem ipsum dolor sit amet, consectetuer adipiscing elit. +Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi, +viverra nec, fringilla in, laoreet vitae, risus. +* Donec sit amet nisl. Aliquam semper ipsum sit amet velit. +Suspendisse id sem consectetuer libero luctus adipiscing. +</code></pre> +<p>If list items are separated by blank lines, Markdown will wrap the +items in <code><p></code> tags in the HTML output. For example, this input:</p> +<pre><code>* Bird +* Magic +</code></pre> +<p>will turn into:</p> +<pre><code><ul> +<li>Bird</li> +<li>Magic</li> +</ul> +</code></pre> +<p>But this:</p> +<pre><code>* Bird + +* Magic +</code></pre> +<p>will turn into:</p> +<pre><code><ul> +<li><p>Bird</p></li> +<li><p>Magic</p></li> +</ul> +</code></pre> +<p>List items may consist of multiple paragraphs. Each subsequent +paragraph in a list item must be intended by either 4 spaces +or one tab:</p> +<pre><code>1. This is a list item with two paragraphs. Lorem ipsum dolor + sit amet, consectetuer adipiscing elit. Aliquam hendrerit + mi posuere lectus. + + Vestibulum enim wisi, viverra nec, fringilla in, laoreet + vitae, risus. Donec sit amet nisl. Aliquam semper ipsum + sit amet velit. + +2. Suspendisse id sem consectetuer libero luctus adipiscing. +</code></pre> +<p>It looks nice if you indent every line of the subsequent +paragraphs, but here again, Markdown will allow you to be +lazy:</p> +<pre><code>* This is a list item with two paragraphs. + + This is the second paragraph in the list item. You're +only required to indent the first line. Lorem ipsum dolor +sit amet, consectetuer adipiscing elit. + +* Another item in the same list. +</code></pre> +<p>To put a blockquote within a list item, the blockquote's <code>></code> +delimiters need to be indented:</p> +<pre><code>* A list item with a blockquote: + + > This is a blockquote + > inside a list item. +</code></pre> +<p>To put a code block within a list item, the code block needs +to be indented <em>twice</em> -- 8 spaces or two tabs:</p> +<pre><code>* A list item with a code block: + + <code goes here> +</code></pre> +<p>It's worth noting that it's possible to trigger an ordered list by +accident, by writing something like this:</p> +<pre><code>1986. What a great season. +</code></pre> +<p>In other words, a <em>number-period-space</em> sequence at the beginning of a +line. To avoid this, you can backslash-escape the period:</p> +<pre><code>1986\. What a great season. +</code></pre> +<h3 id="precode">Code Blocks</h3> + +<p>Pre-formatted code blocks are used for writing about programming or +markup source code. Rather than forming normal paragraphs, the lines +of a code block are interpreted literally. Markdown wraps a code block +in both <code><pre></code> and <code><code></code> tags.</p> +<p>To produce a code block in Markdown, simply indent every line of the +block by at least 4 spaces or 1 tab. For example, given this input:</p> +<pre><code>This is a normal paragraph: + + This is a code block. +</code></pre> +<p>Markdown will generate:</p> +<pre><code><p>This is a normal paragraph:</p> + +<pre><code>This is a code block. +</code></pre> +</code></pre> +<p>One level of indentation -- 4 spaces or 1 tab -- is removed from each +line of the code block. For example, this:</p> +<pre><code>Here is an example of AppleScript: + + tell application "Foo" + beep + end tell +</code></pre> +<p>will turn into:</p> +<pre><code><p>Here is an example of AppleScript:</p> + +<pre><code>tell application "Foo" + beep +end tell +</code></pre> +</code></pre> +<p>A code block continues until it reaches a line that is not indented +(or the end of the article).</p> +<p>Within a code block, ampersands (<code>&</code>) and angle brackets (<code><</code> and <code>></code>) +are automatically converted into HTML entities. This makes it very +easy to include example HTML source code using Markdown -- just paste +it and indent it, and Markdown will handle the hassle of encoding the +ampersands and angle brackets. For example, this:</p> +<pre><code> <div class="footer"> + &copy; 2004 Foo Corporation + </div> +</code></pre> +<p>will turn into:</p> +<pre><code><pre><code>&lt;div class="footer"&gt; + &amp;copy; 2004 Foo Corporation +&lt;/div&gt; +</code></pre> +</code></pre> +<p>Regular Markdown syntax is not processed within code blocks. E.g., +asterisks are just literal asterisks within a code block. This means +it's also easy to use Markdown to write about Markdown's own syntax.</p> +<h3 id="hr">Horizontal Rules</h3> + +<p>You can produce a horizontal rule tag (<code><hr /></code>) by placing three or +more hyphens, asterisks, or underscores on a line by themselves. If you +wish, you may use spaces between the hyphens or asterisks. Each of the +following lines will produce a horizontal rule:</p> +<pre><code>* * * + +*** + +***** + +- - - + +--------------------------------------- + +_ _ _ +</code></pre> +<hr /> +<h2 id="span">Span Elements</h2> + +<h3 id="link">Links</h3> + +<p>Markdown supports two style of links: <em>inline</em> and <em>reference</em>.</p> +<p>In both styles, the link text is delimited by [square brackets].</p> +<p>To create an inline link, use a set of regular parentheses immediately +after the link text's closing square bracket. Inside the parentheses, +put the URL where you want the link to point, along with an <em>optional</em> +title for the link, surrounded in quotes. For example:</p> +<pre><code>This is [an example](http://example.com/ "Title") inline link. + +[This link](http://example.net/) has no title attribute. +</code></pre> +<p>Will produce:</p> +<pre><code><p>This is <a href="http://example.com/" title="Title"> +an example</a> inline link.</p> + +<p><a href="http://example.net/">This link</a> has no +title attribute.</p> +</code></pre> +<p>If you're referring to a local resource on the same server, you can +use relative paths:</p> +<pre><code>See my [About](/about/) page for details. +</code></pre> +<p>Reference-style links use a second set of square brackets, inside +which you place a label of your choosing to identify the link:</p> +<pre><code>This is [an example][id] reference-style link. +</code></pre> +<p>You can optionally use a space to separate the sets of brackets:</p> +<pre><code>This is [an example] [id] reference-style link. +</code></pre> +<p>Then, anywhere in the document, you define your link label like this, +on a line by itself:</p> +<pre><code>[id]: http://example.com/ "Optional Title Here" +</code></pre> +<p>That is:</p> +<ul> +<li>Square brackets containing the link identifier (optionally + indented from the left margin using up to three spaces);</li> +<li>followed by a colon;</li> +<li>followed by one or more spaces (or tabs);</li> +<li>followed by the URL for the link;</li> +<li>optionally followed by a title attribute for the link, enclosed + in double or single quotes.</li> +</ul> +<p>The link URL may, optionally, be surrounded by angle brackets:</p> +<pre><code>[id]: <http://example.com/> "Optional Title Here" +</code></pre> +<p>You can put the title attribute on the next line and use extra spaces +or tabs for padding, which tends to look better with longer URLs:</p> +<pre><code>[id]: http://example.com/longish/path/to/resource/here + "Optional Title Here" +</code></pre> +<p>Link definitions are only used for creating links during Markdown +processing, and are stripped from your document in the HTML output.</p> +<p>Link definition names may constist of letters, numbers, spaces, and punctuation -- but they are <em>not</em> case sensitive. E.g. these two links:</p> +<pre><code>[link text][a] +[link text][A] +</code></pre> +<p>are equivalent.</p> +<p>The <em>implicit link name</em> shortcut allows you to omit the name of the +link, in which case the link text itself is used as the name. +Just use an empty set of square brackets -- e.g., to link the word +"Google" to the google.com web site, you could simply write:</p> +<pre><code>[Google][] +</code></pre> +<p>And then define the link:</p> +<pre><code>[Google]: http://google.com/ +</code></pre> +<p>Because link names may contain spaces, this shortcut even works for +multiple words in the link text:</p> +<pre><code>Visit [Daring Fireball][] for more information. +</code></pre> +<p>And then define the link:</p> +<pre><code>[Daring Fireball]: http://daringfireball.net/ +</code></pre> +<p>Link definitions can be placed anywhere in your Markdown document. I +tend to put them immediately after each paragraph in which they're +used, but if you want, you can put them all at the end of your +document, sort of like footnotes.</p> +<p>Here's an example of reference links in action:</p> +<pre><code>I get 10 times more traffic from [Google] [1] than from +[Yahoo] [2] or [MSN] [3]. + + [1]: http://google.com/ "Google" + [2]: http://search.yahoo.com/ "Yahoo Search" + [3]: http://search.msn.com/ "MSN Search" +</code></pre> +<p>Using the implicit link name shortcut, you could instead write:</p> +<pre><code>I get 10 times more traffic from [Google][] than from +[Yahoo][] or [MSN][]. + + [google]: http://google.com/ "Google" + [yahoo]: http://search.yahoo.com/ "Yahoo Search" + [msn]: http://search.msn.com/ "MSN Search" +</code></pre> +<p>Both of the above examples will produce the following HTML output:</p> +<pre><code><p>I get 10 times more traffic from <a href="http://google.com/" +title="Google">Google</a> than from +<a href="http://search.yahoo.com/" title="Yahoo Search">Yahoo</a> +or <a href="http://search.msn.com/" title="MSN Search">MSN</a>.</p> +</code></pre> +<p>For comparison, here is the same paragraph written using +Markdown's inline link style:</p> +<pre><code>I get 10 times more traffic from [Google](http://google.com/ "Google") +than from [Yahoo](http://search.yahoo.com/ "Yahoo Search") or +[MSN](http://search.msn.com/ "MSN Search"). +</code></pre> +<p>The point of reference-style links is not that they're easier to +write. The point is that with reference-style links, your document +source is vastly more readable. Compare the above examples: using +reference-style links, the paragraph itself is only 81 characters +long; with inline-style links, it's 176 characters; and as raw HTML, +it's 234 characters. In the raw HTML, there's more markup than there +is text.</p> +<p>With Markdown's reference-style links, a source document much more +closely resembles the final output, as rendered in a browser. By +allowing you to move the markup-related metadata out of the paragraph, +you can add links without interrupting the narrative flow of your +prose.</p> +<h3 id="em">Emphasis</h3> + +<p>Markdown treats asterisks (<code>*</code>) and underscores (<code>_</code>) as indicators of +emphasis. Text wrapped with one <code>*</code> or <code>_</code> will be wrapped with an +HTML <code><em></code> tag; double <code>*</code>'s or <code>_</code>'s will be wrapped with an HTML +<code><strong></code> tag. E.g., this input:</p> +<pre><code>*single asterisks* + +_single underscores_ + +**double asterisks** + +__double underscores__ +</code></pre> +<p>will produce:</p> +<pre><code><em>single asterisks</em> + +<em>single underscores</em> + +<strong>double asterisks</strong> + +<strong>double underscores</strong> +</code></pre> +<p>You can use whichever style you prefer; the lone restriction is that +the same character must be used to open and close an emphasis span.</p> +<p>Emphasis can be used in the middle of a word:</p> +<pre><code>un*fucking*believable +</code></pre> +<p>But if you surround an <code>*</code> or <code>_</code> with spaces, it'll be treated as a +literal asterisk or underscore.</p> +<p>To produce a literal asterisk or underscore at a position where it +would otherwise be used as an emphasis delimiter, you can backslash +escape it:</p> +<pre><code>\*this text is surrounded by literal asterisks\* +</code></pre> +<h3 id="code">Code</h3> + +<p>To indicate a span of code, wrap it with backtick quotes (<code>`</code>). +Unlike a pre-formatted code block, a code span indicates code within a +normal paragraph. For example:</p> +<pre><code>Use the `printf()` function. +</code></pre> +<p>will produce:</p> +<pre><code><p>Use the <code>printf()</code> function.</p> +</code></pre> +<p>To include a literal backtick character within a code span, you can use +multiple backticks as the opening and closing delimiters:</p> +<pre><code>``There is a literal backtick (`) here.`` +</code></pre> +<p>which will produce this:</p> +<pre><code><p><code>There is a literal backtick (`) here.</code></p> +</code></pre> +<p>The backtick delimiters surrounding a code span may include spaces -- +one after the opening, one before the closing. This allows you to place +literal backtick characters at the beginning or end of a code span:</p> +<pre><code>A single backtick in a code span: `` ` `` + +A backtick-delimited string in a code span: `` `foo` `` +</code></pre> +<p>will produce:</p> +<pre><code><p>A single backtick in a code span: <code>`</code></p> + +<p>A backtick-delimited string in a code span: <code>`foo`</code></p> +</code></pre> +<p>With a code span, ampersands and angle brackets are encoded as HTML +entities automatically, which makes it easy to include example HTML +tags. Markdown will turn this:</p> +<pre><code>Please don't use any `<blink>` tags. +</code></pre> +<p>into:</p> +<pre><code><p>Please don't use any <code>&lt;blink&gt;</code> tags.</p> +</code></pre> +<p>You can write this:</p> +<pre><code>`&#8212;` is the decimal-encoded equivalent of `&mdash;`. +</code></pre> +<p>to produce:</p> +<pre><code><p><code>&amp;#8212;</code> is the decimal-encoded +equivalent of <code>&amp;mdash;</code>.</p> +</code></pre> +<h3 id="img">Images</h3> + +<p>Admittedly, it's fairly difficult to devise a "natural" syntax for +placing images into a plain text document format.</p> +<p>Markdown uses an image syntax that is intended to resemble the syntax +for links, allowing for two styles: <em>inline</em> and <em>reference</em>.</p> +<p>Inline image syntax looks like this:</p> +<pre><code> + + +</code></pre> +<p>That is:</p> +<ul> +<li>An exclamation mark: <code>!</code>;</li> +<li>followed by a set of square brackets, containing the <code>alt</code> + attribute text for the image;</li> +<li>followed by a set of parentheses, containing the URL or path to + the image, and an optional <code>title</code> attribute enclosed in double + or single quotes.</li> +</ul> +<p>Reference-style image syntax looks like this:</p> +<pre><code>![Alt text][id] +</code></pre> +<p>Where "id" is the name of a defined image reference. Image references +are defined using syntax identical to link references:</p> +<pre><code>[id]: url/to/image "Optional title attribute" +</code></pre> +<p>As of this writing, Markdown has no syntax for specifying the +dimensions of an image; if this is important to you, you can simply +use regular HTML <code><img></code> tags.</p> +<hr /> +<h2 id="misc">Miscellaneous</h2> + +<h3 id="autolink">Automatic Links</h3> + +<p>Markdown supports a shortcut style for creating "automatic" links for URLs and email addresses: simply surround the URL or email address with angle brackets. What this means is that if you want to show the actual text of a URL or email address, and also have it be a clickable link, you can do this:</p> +<pre><code><http://example.com/> +</code></pre> +<p>Markdown will turn this into:</p> +<pre><code><a href="http://example.com/">http://example.com/</a> +</code></pre> +<p>Automatic links for email addresses work similarly, except that +Markdown will also perform a bit of randomized decimal and hex +entity-encoding to help obscure your address from address-harvesting +spambots. For example, Markdown will turn this:</p> +<pre><code><address@example.com> +</code></pre> +<p>into something like this:</p> +<pre><code><a href="&#x6D;&#x61;i&#x6C;&#x74;&#x6F;:&#x61;&#x64;&#x64;&#x72;&#x65; +&#115;&#115;&#64;&#101;&#120;&#x61;&#109;&#x70;&#x6C;e&#x2E;&#99;&#111; +&#109;">&#x61;&#x64;&#x64;&#x72;&#x65;&#115;&#115;&#64;&#101;&#120;&#x61; +&#109;&#x70;&#x6C;e&#x2E;&#99;&#111;&#109;</a> +</code></pre> +<p>which will render in a browser as a clickable link to "address@example.com".</p> +<p>(This sort of entity-encoding trick will indeed fool many, if not +most, address-harvesting bots, but it definitely won't fool all of +them. It's better than nothing, but an address published in this way +will probably eventually start receiving spam.)</p> +<h3 id="backslash">Backslash Escapes</h3> + +<p>Markdown allows you to use backslash escapes to generate literal +characters which would otherwise have special meaning in Markdown's +formatting syntax. For example, if you wanted to surround a word with +literal asterisks (instead of an HTML <code><em></code> tag), you can backslashes +before the asterisks, like this:</p> +<pre><code>\*literal asterisks\* +</code></pre> +<p>Markdown provides backslash escapes for the following characters:</p> +<pre><code>\ backslash +` backtick +* asterisk +_ underscore +{} curly braces +[] square brackets +() parentheses +# hash mark ++ plus sign +- minus sign (hyphen) +. dot +! exclamation mark +</code></pre>
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