mirror of
https://github.com/Luzifer/mondash.git
synced 2024-12-23 20:41:17 +00:00
888 lines
27 KiB
Text
888 lines
27 KiB
Text
Markdown: Syntax
|
|
================
|
|
|
|
<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>
|
|
|
|
|
|
* [Overview](#overview)
|
|
* [Philosophy](#philosophy)
|
|
* [Inline HTML](#html)
|
|
* [Automatic Escaping for Special Characters](#autoescape)
|
|
* [Block Elements](#block)
|
|
* [Paragraphs and Line Breaks](#p)
|
|
* [Headers](#header)
|
|
* [Blockquotes](#blockquote)
|
|
* [Lists](#list)
|
|
* [Code Blocks](#precode)
|
|
* [Horizontal Rules](#hr)
|
|
* [Span Elements](#span)
|
|
* [Links](#link)
|
|
* [Emphasis](#em)
|
|
* [Code](#code)
|
|
* [Images](#img)
|
|
* [Miscellaneous](#misc)
|
|
* [Backslash Escapes](#backslash)
|
|
* [Automatic Links](#autolink)
|
|
|
|
|
|
**Note:** This document is itself written using Markdown; you
|
|
can [see the source for it by adding '.text' to the URL][src].
|
|
|
|
[src]: /projects/markdown/syntax.text
|
|
|
|
* * *
|
|
|
|
<h2 id="overview">Overview</h2>
|
|
|
|
<h3 id="philosophy">Philosophy</h3>
|
|
|
|
Markdown is intended to be as easy-to-read and easy-to-write as is feasible.
|
|
|
|
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 [Setext] [1], [atx] [2], [Textile] [3], [reStructuredText] [4],
|
|
[Grutatext] [5], and [EtText] [6] -- the single biggest source of
|
|
inspiration for Markdown's syntax is the format of plain text email.
|
|
|
|
[1]: http://docutils.sourceforge.net/mirror/setext.html
|
|
[2]: http://www.aaronsw.com/2002/atx/
|
|
[3]: http://textism.com/tools/textile/
|
|
[4]: http://docutils.sourceforge.net/rst.html
|
|
[5]: http://www.triptico.com/software/grutatxt.html
|
|
[6]: http://ettext.taint.org/doc/
|
|
|
|
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.
|
|
|
|
|
|
|
|
<h3 id="html">Inline HTML</h3>
|
|
|
|
Markdown's syntax is intended for one purpose: to be used as a
|
|
format for *writing* for the web.
|
|
|
|
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 *not* 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 *publishing* format; Markdown is a *writing*
|
|
format. Thus, Markdown's formatting syntax only addresses issues that
|
|
can be conveyed in plain text.
|
|
|
|
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.
|
|
|
|
The only restrictions are that block-level HTML elements -- e.g. `<div>`,
|
|
`<table>`, `<pre>`, `<p>`, 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) `<p>` tags around HTML block-level tags.
|
|
|
|
For example, to add an HTML table to a Markdown article:
|
|
|
|
This is a regular paragraph.
|
|
|
|
<table>
|
|
<tr>
|
|
<td>Foo</td>
|
|
</tr>
|
|
</table>
|
|
|
|
This is another regular paragraph.
|
|
|
|
Note that Markdown formatting syntax is not processed within block-level
|
|
HTML tags. E.g., you can't use Markdown-style `*emphasis*` inside an
|
|
HTML block.
|
|
|
|
Span-level HTML tags -- e.g. `<span>`, `<cite>`, or `<del>` -- 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 `<a>` or `<img>` tags instead of Markdown's
|
|
link or image syntax, go right ahead.
|
|
|
|
Unlike block-level HTML tags, Markdown syntax *is* processed within
|
|
span-level tags.
|
|
|
|
|
|
<h3 id="autoescape">Automatic Escaping for Special Characters</h3>
|
|
|
|
In HTML, there are two characters that demand special treatment: `<`
|
|
and `&`. 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. `<`, and
|
|
`&`.
|
|
|
|
Ampersands in particular are bedeviling for web writers. If you want to
|
|
write about 'AT&T', you need to write '`AT&T`'. You even need to
|
|
escape ampersands within URLs. Thus, if you want to link to:
|
|
|
|
http://images.google.com/images?num=30&q=larry+bird
|
|
|
|
you need to encode the URL as:
|
|
|
|
http://images.google.com/images?num=30&q=larry+bird
|
|
|
|
in your anchor tag `href` 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.
|
|
|
|
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 `&`.
|
|
|
|
So, if you want to include a copyright symbol in your article, you can write:
|
|
|
|
©
|
|
|
|
and Markdown will leave it alone. But if you write:
|
|
|
|
AT&T
|
|
|
|
Markdown will translate it to:
|
|
|
|
AT&T
|
|
|
|
Similarly, because Markdown supports [inline HTML](#html), if you use
|
|
angle brackets as delimiters for HTML tags, Markdown will treat them as
|
|
such. But if you write:
|
|
|
|
4 < 5
|
|
|
|
Markdown will translate it to:
|
|
|
|
4 < 5
|
|
|
|
However, inside Markdown code spans and blocks, angle brackets and
|
|
ampersands are *always* 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 `<`
|
|
and `&` in your example code needs to be escaped.)
|
|
|
|
|
|
* * *
|
|
|
|
|
|
<h2 id="block">Block Elements</h2>
|
|
|
|
|
|
<h3 id="p">Paragraphs and Line Breaks</h3>
|
|
|
|
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.
|
|
|
|
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 `<br />` tag.
|
|
|
|
When you *do* want to insert a `<br />` break tag using Markdown, you
|
|
end a line with two or more spaces, then type return.
|
|
|
|
Yes, this takes a tad more effort to create a `<br />`, but a simplistic
|
|
"every line break is a `<br />`" rule wouldn't work for Markdown.
|
|
Markdown's email-style [blockquoting][bq] and multi-paragraph [list items][l]
|
|
work best -- and look better -- when you format them with hard breaks.
|
|
|
|
[bq]: #blockquote
|
|
[l]: #list
|
|
|
|
|
|
|
|
<h3 id="header">Headers</h3>
|
|
|
|
Markdown supports two styles of headers, [Setext] [1] and [atx] [2].
|
|
|
|
Setext-style headers are "underlined" using equal signs (for first-level
|
|
headers) and dashes (for second-level headers). For example:
|
|
|
|
This is an H1
|
|
=============
|
|
|
|
This is an H2
|
|
-------------
|
|
|
|
Any number of underlining `=`'s or `-`'s will work.
|
|
|
|
Atx-style headers use 1-6 hash characters at the start of the line,
|
|
corresponding to header levels 1-6. For example:
|
|
|
|
# This is an H1
|
|
|
|
## This is an H2
|
|
|
|
###### This is an H6
|
|
|
|
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.) :
|
|
|
|
# This is an H1 #
|
|
|
|
## This is an H2 ##
|
|
|
|
### This is an H3 ######
|
|
|
|
|
|
<h3 id="blockquote">Blockquotes</h3>
|
|
|
|
Markdown uses email-style `>` 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 `>` before every line:
|
|
|
|
> 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.
|
|
|
|
Markdown allows you to be lazy and only put the `>` before the first
|
|
line of a hard-wrapped paragraph:
|
|
|
|
> 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.
|
|
|
|
Blockquotes can be nested (i.e. a blockquote-in-a-blockquote) by
|
|
adding additional levels of `>`:
|
|
|
|
> This is the first level of quoting.
|
|
>
|
|
> > This is nested blockquote.
|
|
>
|
|
> Back to the first level.
|
|
|
|
Blockquotes can contain other Markdown elements, including headers, lists,
|
|
and code blocks:
|
|
|
|
> ## 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");
|
|
|
|
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.
|
|
|
|
|
|
<h3 id="list">Lists</h3>
|
|
|
|
Markdown supports ordered (numbered) and unordered (bulleted) lists.
|
|
|
|
Unordered lists use asterisks, pluses, and hyphens -- interchangably
|
|
-- as list markers:
|
|
|
|
* Red
|
|
* Green
|
|
* Blue
|
|
|
|
is equivalent to:
|
|
|
|
+ Red
|
|
+ Green
|
|
+ Blue
|
|
|
|
and:
|
|
|
|
- Red
|
|
- Green
|
|
- Blue
|
|
|
|
Ordered lists use numbers followed by periods:
|
|
|
|
1. Bird
|
|
2. McHale
|
|
3. Parish
|
|
|
|
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:
|
|
|
|
<ol>
|
|
<li>Bird</li>
|
|
<li>McHale</li>
|
|
<li>Parish</li>
|
|
</ol>
|
|
|
|
If you instead wrote the list in Markdown like this:
|
|
|
|
1. Bird
|
|
1. McHale
|
|
1. Parish
|
|
|
|
or even:
|
|
|
|
3. Bird
|
|
1. McHale
|
|
8. Parish
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
To make lists look nice, you can wrap items with hanging indents:
|
|
|
|
* 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.
|
|
|
|
But if you want to be lazy, you don't have to:
|
|
|
|
* 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.
|
|
|
|
If list items are separated by blank lines, Markdown will wrap the
|
|
items in `<p>` tags in the HTML output. For example, this input:
|
|
|
|
* Bird
|
|
* Magic
|
|
|
|
will turn into:
|
|
|
|
<ul>
|
|
<li>Bird</li>
|
|
<li>Magic</li>
|
|
</ul>
|
|
|
|
But this:
|
|
|
|
* Bird
|
|
|
|
* Magic
|
|
|
|
will turn into:
|
|
|
|
<ul>
|
|
<li><p>Bird</p></li>
|
|
<li><p>Magic</p></li>
|
|
</ul>
|
|
|
|
List items may consist of multiple paragraphs. Each subsequent
|
|
paragraph in a list item must be intended by either 4 spaces
|
|
or one tab:
|
|
|
|
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.
|
|
|
|
It looks nice if you indent every line of the subsequent
|
|
paragraphs, but here again, Markdown will allow you to be
|
|
lazy:
|
|
|
|
* 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.
|
|
|
|
To put a blockquote within a list item, the blockquote's `>`
|
|
delimiters need to be indented:
|
|
|
|
* A list item with a blockquote:
|
|
|
|
> This is a blockquote
|
|
> inside a list item.
|
|
|
|
To put a code block within a list item, the code block needs
|
|
to be indented *twice* -- 8 spaces or two tabs:
|
|
|
|
* A list item with a code block:
|
|
|
|
<code goes here>
|
|
|
|
|
|
It's worth noting that it's possible to trigger an ordered list by
|
|
accident, by writing something like this:
|
|
|
|
1986. What a great season.
|
|
|
|
In other words, a *number-period-space* sequence at the beginning of a
|
|
line. To avoid this, you can backslash-escape the period:
|
|
|
|
1986\. What a great season.
|
|
|
|
|
|
|
|
<h3 id="precode">Code Blocks</h3>
|
|
|
|
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 `<pre>` and `<code>` tags.
|
|
|
|
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:
|
|
|
|
This is a normal paragraph:
|
|
|
|
This is a code block.
|
|
|
|
Markdown will generate:
|
|
|
|
<p>This is a normal paragraph:</p>
|
|
|
|
<pre><code>This is a code block.
|
|
</code></pre>
|
|
|
|
One level of indentation -- 4 spaces or 1 tab -- is removed from each
|
|
line of the code block. For example, this:
|
|
|
|
Here is an example of AppleScript:
|
|
|
|
tell application "Foo"
|
|
beep
|
|
end tell
|
|
|
|
will turn into:
|
|
|
|
<p>Here is an example of AppleScript:</p>
|
|
|
|
<pre><code>tell application "Foo"
|
|
beep
|
|
end tell
|
|
</code></pre>
|
|
|
|
A code block continues until it reaches a line that is not indented
|
|
(or the end of the article).
|
|
|
|
Within a code block, ampersands (`&`) and angle brackets (`<` and `>`)
|
|
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:
|
|
|
|
<div class="footer">
|
|
© 2004 Foo Corporation
|
|
</div>
|
|
|
|
will turn into:
|
|
|
|
<pre><code><div class="footer">
|
|
&copy; 2004 Foo Corporation
|
|
</div>
|
|
</code></pre>
|
|
|
|
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.
|
|
|
|
|
|
|
|
<h3 id="hr">Horizontal Rules</h3>
|
|
|
|
You can produce a horizontal rule tag (`<hr />`) 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:
|
|
|
|
* * *
|
|
|
|
***
|
|
|
|
*****
|
|
|
|
- - -
|
|
|
|
---------------------------------------
|
|
|
|
_ _ _
|
|
|
|
|
|
* * *
|
|
|
|
<h2 id="span">Span Elements</h2>
|
|
|
|
<h3 id="link">Links</h3>
|
|
|
|
Markdown supports two style of links: *inline* and *reference*.
|
|
|
|
In both styles, the link text is delimited by [square brackets].
|
|
|
|
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 *optional*
|
|
title for the link, surrounded in quotes. For example:
|
|
|
|
This is [an example](http://example.com/ "Title") inline link.
|
|
|
|
[This link](http://example.net/) has no title attribute.
|
|
|
|
Will produce:
|
|
|
|
<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>
|
|
|
|
If you're referring to a local resource on the same server, you can
|
|
use relative paths:
|
|
|
|
See my [About](/about/) page for details.
|
|
|
|
Reference-style links use a second set of square brackets, inside
|
|
which you place a label of your choosing to identify the link:
|
|
|
|
This is [an example][id] reference-style link.
|
|
|
|
You can optionally use a space to separate the sets of brackets:
|
|
|
|
This is [an example] [id] reference-style link.
|
|
|
|
Then, anywhere in the document, you define your link label like this,
|
|
on a line by itself:
|
|
|
|
[id]: http://example.com/ "Optional Title Here"
|
|
|
|
That is:
|
|
|
|
* Square brackets containing the link identifier (optionally
|
|
indented from the left margin using up to three spaces);
|
|
* followed by a colon;
|
|
* followed by one or more spaces (or tabs);
|
|
* followed by the URL for the link;
|
|
* optionally followed by a title attribute for the link, enclosed
|
|
in double or single quotes.
|
|
|
|
The link URL may, optionally, be surrounded by angle brackets:
|
|
|
|
[id]: <http://example.com/> "Optional Title Here"
|
|
|
|
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:
|
|
|
|
[id]: http://example.com/longish/path/to/resource/here
|
|
"Optional Title Here"
|
|
|
|
Link definitions are only used for creating links during Markdown
|
|
processing, and are stripped from your document in the HTML output.
|
|
|
|
Link definition names may constist of letters, numbers, spaces, and punctuation -- but they are *not* case sensitive. E.g. these two links:
|
|
|
|
[link text][a]
|
|
[link text][A]
|
|
|
|
are equivalent.
|
|
|
|
The *implicit link name* 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:
|
|
|
|
[Google][]
|
|
|
|
And then define the link:
|
|
|
|
[Google]: http://google.com/
|
|
|
|
Because link names may contain spaces, this shortcut even works for
|
|
multiple words in the link text:
|
|
|
|
Visit [Daring Fireball][] for more information.
|
|
|
|
And then define the link:
|
|
|
|
[Daring Fireball]: http://daringfireball.net/
|
|
|
|
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.
|
|
|
|
Here's an example of reference links in action:
|
|
|
|
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"
|
|
|
|
Using the implicit link name shortcut, you could instead write:
|
|
|
|
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"
|
|
|
|
Both of the above examples will produce the following HTML output:
|
|
|
|
<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>
|
|
|
|
For comparison, here is the same paragraph written using
|
|
Markdown's inline link style:
|
|
|
|
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").
|
|
|
|
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.
|
|
|
|
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.
|
|
|
|
|
|
<h3 id="em">Emphasis</h3>
|
|
|
|
Markdown treats asterisks (`*`) and underscores (`_`) as indicators of
|
|
emphasis. Text wrapped with one `*` or `_` will be wrapped with an
|
|
HTML `<em>` tag; double `*`'s or `_`'s will be wrapped with an HTML
|
|
`<strong>` tag. E.g., this input:
|
|
|
|
*single asterisks*
|
|
|
|
_single underscores_
|
|
|
|
**double asterisks**
|
|
|
|
__double underscores__
|
|
|
|
will produce:
|
|
|
|
<em>single asterisks</em>
|
|
|
|
<em>single underscores</em>
|
|
|
|
<strong>double asterisks</strong>
|
|
|
|
<strong>double underscores</strong>
|
|
|
|
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.
|
|
|
|
Emphasis can be used in the middle of a word:
|
|
|
|
un*fucking*believable
|
|
|
|
But if you surround an `*` or `_` with spaces, it'll be treated as a
|
|
literal asterisk or underscore.
|
|
|
|
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:
|
|
|
|
\*this text is surrounded by literal asterisks\*
|
|
|
|
|
|
|
|
<h3 id="code">Code</h3>
|
|
|
|
To indicate a span of code, wrap it with backtick quotes (`` ` ``).
|
|
Unlike a pre-formatted code block, a code span indicates code within a
|
|
normal paragraph. For example:
|
|
|
|
Use the `printf()` function.
|
|
|
|
will produce:
|
|
|
|
<p>Use the <code>printf()</code> function.</p>
|
|
|
|
To include a literal backtick character within a code span, you can use
|
|
multiple backticks as the opening and closing delimiters:
|
|
|
|
``There is a literal backtick (`) here.``
|
|
|
|
which will produce this:
|
|
|
|
<p><code>There is a literal backtick (`) here.</code></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:
|
|
|
|
A single backtick in a code span: `` ` ``
|
|
|
|
A backtick-delimited string in a code span: `` `foo` ``
|
|
|
|
will produce:
|
|
|
|
<p>A single backtick in a code span: <code>`</code></p>
|
|
|
|
<p>A backtick-delimited string in a code span: <code>`foo`</code></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:
|
|
|
|
Please don't use any `<blink>` tags.
|
|
|
|
into:
|
|
|
|
<p>Please don't use any <code><blink></code> tags.</p>
|
|
|
|
You can write this:
|
|
|
|
`—` is the decimal-encoded equivalent of `—`.
|
|
|
|
to produce:
|
|
|
|
<p><code>&#8212;</code> is the decimal-encoded
|
|
equivalent of <code>&mdash;</code>.</p>
|
|
|
|
|
|
|
|
<h3 id="img">Images</h3>
|
|
|
|
Admittedly, it's fairly difficult to devise a "natural" syntax for
|
|
placing images into a plain text document format.
|
|
|
|
Markdown uses an image syntax that is intended to resemble the syntax
|
|
for links, allowing for two styles: *inline* and *reference*.
|
|
|
|
Inline image syntax looks like this:
|
|
|
|
|
|
|
|
|
|
|
|
That is:
|
|
|
|
* An exclamation mark: `!`;
|
|
* followed by a set of square brackets, containing the `alt`
|
|
attribute text for the image;
|
|
* followed by a set of parentheses, containing the URL or path to
|
|
the image, and an optional `title` attribute enclosed in double
|
|
or single quotes.
|
|
|
|
Reference-style image syntax looks like this:
|
|
|
|
![Alt text][id]
|
|
|
|
Where "id" is the name of a defined image reference. Image references
|
|
are defined using syntax identical to link references:
|
|
|
|
[id]: url/to/image "Optional title attribute"
|
|
|
|
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 `<img>` tags.
|
|
|
|
|
|
* * *
|
|
|
|
|
|
<h2 id="misc">Miscellaneous</h2>
|
|
|
|
<h3 id="autolink">Automatic Links</h3>
|
|
|
|
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:
|
|
|
|
<http://example.com/>
|
|
|
|
Markdown will turn this into:
|
|
|
|
<a href="http://example.com/">http://example.com/</a>
|
|
|
|
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:
|
|
|
|
<address@example.com>
|
|
|
|
into something like this:
|
|
|
|
<a href="mailto:addre
|
|
ss@example.co
|
|
m">address@exa
|
|
mple.com</a>
|
|
|
|
which will render in a browser as a clickable link to "address@example.com".
|
|
|
|
(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.)
|
|
|
|
|
|
|
|
<h3 id="backslash">Backslash Escapes</h3>
|
|
|
|
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 `<em>` tag), you can backslashes
|
|
before the asterisks, like this:
|
|
|
|
\*literal asterisks\*
|
|
|
|
Markdown provides backslash escapes for the following characters:
|
|
|
|
\ backslash
|
|
` backtick
|
|
* asterisk
|
|
_ underscore
|
|
{} curly braces
|
|
[] square brackets
|
|
() parentheses
|
|
# hash mark
|
|
+ plus sign
|
|
- minus sign (hyphen)
|
|
. dot
|
|
! exclamation mark
|
|
|