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authorBjørn Erik Pedersen <bjorn.erik.pedersen@gmail.com>2019-08-16 16:21:03 +0200
committerBjørn Erik Pedersen <bjorn.erik.pedersen@gmail.com>2019-08-16 16:24:21 +0200
commit416493b548a9bbaa27758fba9bab50a22b680e9d (patch)
treec0b6ca6e880e261296b8f20409cc4322420618f4 /hugolib/testdata
parentf28efd35820dc4909832c14dfd8ea6812ecead31 (diff)
hugolib: Add a site benchmark
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+# Introduction
+
+## What is Markdown?
+
+Markdown is a plain text format for writing structured documents,
+based on conventions for indicating formatting in email
+and usenet posts. It was developed by John Gruber (with
+help from Aaron Swartz) and released in 2004 in the form of a
+[syntax description](http://daringfireball.net/projects/markdown/syntax)
+and a Perl script (`Markdown.pl`) for converting Markdown to
+HTML. In the next decade, dozens of implementations were
+developed in many languages. Some extended the original
+Markdown syntax with conventions for footnotes, tables, and
+other document elements. Some allowed Markdown documents to be
+rendered in formats other than HTML. Websites like Reddit,
+StackOverflow, and GitHub had millions of people using Markdown.
+And Markdown started to be used beyond the web, to author books,
+articles, slide shows, letters, and lecture notes.
+
+What distinguishes Markdown from many other lightweight markup
+syntaxes, which are often easier to write, is its readability.
+As Gruber writes:
+
+> The overriding design goal for Markdown's formatting syntax is
+> to make it as readable as possible. The idea is that 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.
+> (<http://daringfireball.net/projects/markdown/>)
+
+The point can be illustrated by comparing a sample of
+[AsciiDoc](http://www.methods.co.nz/asciidoc/) with
+an equivalent sample of Markdown. Here is a sample of
+AsciiDoc from the AsciiDoc manual:
+
+```
+1. List item one.
++
+List item one continued with a second paragraph followed by an
+Indented block.
++
+.................
+$ ls *.sh
+$ mv *.sh ~/tmp
+.................
++
+List item continued with a third paragraph.
+
+2. List item two continued with an open block.
++
+--
+This paragraph is part of the preceding list item.
+
+a. This list is nested and does not require explicit item
+continuation.
++
+This paragraph is part of the preceding list item.
+
+b. List item b.
+
+This paragraph belongs to item two of the outer list.
+--
+```
+
+And here is the equivalent in Markdown:
+```
+1. List item one.
+
+ List item one continued with a second paragraph followed by an
+ Indented block.
+
+ $ ls *.sh
+ $ mv *.sh ~/tmp
+
+ List item continued with a third paragraph.
+
+2. List item two continued with an open block.
+
+ This paragraph is part of the preceding list item.
+
+ 1. This list is nested and does not require explicit item continuation.
+
+ This paragraph is part of the preceding list item.
+
+ 2. List item b.
+
+ This paragraph belongs to item two of the outer list.
+```
+
+The AsciiDoc version is, arguably, easier to write. You don't need
+to worry about indentation. But the Markdown version is much easier
+to read. The nesting of list items is apparent to the eye in the
+source, not just in the processed document.
+
+## Why is a spec needed?
+
+John Gruber's [canonical description of Markdown's
+syntax](http://daringfireball.net/projects/markdown/syntax)
+does not specify the syntax unambiguously. Here are some examples of
+questions it does not answer:
+
+1. How much indentation is needed for a sublist? The spec says that
+ continuation paragraphs need to be indented four spaces, but is
+ not fully explicit about sublists. It is natural to think that
+ they, too, must be indented four spaces, but `Markdown.pl` does
+ not require that. This is hardly a "corner case," and divergences
+ between implementations on this issue often lead to surprises for
+ users in real documents. (See [this comment by John
+ Gruber](http://article.gmane.org/gmane.text.markdown.general/1997).)
+
+2. Is a blank line needed before a block quote or heading?
+ Most implementations do not require the blank line. However,
+ this can lead to unexpected results in hard-wrapped text, and
+ also to ambiguities in parsing (note that some implementations
+ put the heading inside the blockquote, while others do not).
+ (John Gruber has also spoken [in favor of requiring the blank
+ lines](http://article.gmane.org/gmane.text.markdown.general/2146).)
+
+3. Is a blank line needed before an indented code block?
+ (`Markdown.pl` requires it, but this is not mentioned in the
+ documentation, and some implementations do not require it.)
+
+ ``` markdown
+ paragraph
+ code?
+ ```
+
+4. What is the exact rule for determining when list items get
+ wrapped in `<p>` tags? Can a list be partially "loose" and partially
+ "tight"? What should we do with a list like this?
+
+ ``` markdown
+ 1. one
+
+ 2. two
+ 3. three
+ ```
+
+ Or this?
+
+ ``` markdown
+ 1. one
+ - a
+
+ - b
+ 2. two
+ ```
+
+ (There are some relevant comments by John Gruber
+ [here](http://article.gmane.org/gmane.text.markdown.general/2554).)
+
+5. Can list markers be indented? Can ordered list markers be right-aligned?
+
+ ``` markdown
+ 8. item 1
+ 9. item 2
+ 10. item 2a
+ ```
+
+6. Is this one list with a thematic break in its second item,
+ or two lists separated by a thematic break?
+
+ ``` markdown
+ * a
+ * * * * *
+ * b
+ ```
+
+7. When list markers change from numbers to bullets, do we have
+ two lists or one? (The Markdown syntax description suggests two,
+ but the perl scripts and many other implementations produce one.)
+
+ ``` markdown
+ 1. fee
+ 2. fie
+ - foe
+ - fum
+ ```
+
+8. What are the precedence rules for the markers of inline structure?
+ For example, is the following a valid link, or does the code span
+ take precedence ?
+
+ ``` markdown
+ [a backtick (`)](/url) and [another backtick (`)](/url).
+ ```
+
+9. What are the precedence rules for markers of emphasis and strong
+ emphasis? For example, how should the following be parsed?
+
+ ``` markdown
+ *foo *bar* baz*
+ ```
+
+10. What are the precedence rules between block-level and inline-level
+ structure? For example, how should the following be parsed?
+
+ ``` markdown
+ - `a long code span can contain a hyphen like this
+ - and it can screw things up`
+ ```
+
+11. Can list items include section headings? (`Markdown.pl` does not
+ allow this, but does allow blockquotes to include headings.)
+
+ ``` markdown
+ - # Heading
+ ```
+
+12. Can list items be empty?
+
+ ``` markdown
+ * a
+ *
+ * b
+ ```
+
+13. Can link references be defined inside block quotes or list items?
+
+ ``` markdown
+ > Blockquote [foo].
+ >
+ > [foo]: /url
+ ```
+
+14. If there are multiple definitions for the same reference, which takes
+ precedence?
+
+ ``` markdown
+ [foo]: /url1
+ [foo]: /url2
+
+ [foo][]
+ ```
+
+In the absence of a spec, early implementers consulted `Markdown.pl`
+to resolve these ambiguities. But `Markdown.pl` was quite buggy, and
+gave manifestly bad results in many cases, so it was not a
+satisfactory replacement for a spec.
+
+Because there is no unambiguous spec, implementations have diverged
+considerably. As a result, users are often surprised to find that
+a document that renders one way on one system (say, a GitHub wiki)
+renders differently on another (say, converting to docbook using
+pandoc). To make matters worse, because nothing in Markdown counts
+as a "syntax error," the divergence often isn't discovered right away.
+
+## About this document
+
+This document attempts to specify Markdown syntax unambiguously.
+It contains many examples with side-by-side Markdown and
+HTML. These are intended to double as conformance tests. An
+accompanying script `spec_tests.py` can be used to run the tests
+against any Markdown program:
+
+ python test/spec_tests.py --spec spec.txt --program PROGRAM
+
+Since this document describes how Markdown is to be parsed into
+an abstract syntax tree, it would have made sense to use an abstract
+representation of the syntax tree instead of HTML. But HTML is capable
+of representing the structural distinctions we need to make, and the
+choice of HTML for the tests makes it possible to run the tests against
+an implementation without writing an abstract syntax tree renderer.
+
+This document is generated from a text file, `spec.txt`, written
+in Markdown with a small extension for the side-by-side tests.
+The script `tools/makespec.py` can be used to convert `spec.txt` into
+HTML or CommonMark (which can then be converted into other formats).
+
+In the examples, the `→` character is used to represent tabs.
+
+# Preliminaries
+
+## Characters and lines
+
+Any sequence of [characters] is a valid CommonMark
+document.
+
+A [character](@) is a Unicode code point. Although some
+code points (for example, combining accents) do not correspond to
+characters in an intuitive sense, all code points count as characters
+for purposes of this spec.
+
+This spec does not specify an encoding; it thinks of lines as composed
+of [characters] rather than bytes. A conforming parser may be limited
+to a certain encoding.
+
+A [line](@) is a sequence of zero or more [characters]
+other than newline (`U+000A`) or carriage return (`U+000D`),
+followed by a [line ending] or by the end of file.
+
+A [line ending](@) is a newline (`U+000A`), a carriage return
+(`U+000D`) not followed by a newline, or a carriage return and a
+following newline.
+
+A line containing no characters, or a line containing only spaces
+(`U+0020`) or tabs (`U+0009`), is called a [blank line](@).
+
+The following definitions of character classes will be used in this spec:
+
+A [whitespace character](@) is a space
+(`U+0020`), tab (`U+0009`), newline (`U+000A`), line tabulation (`U+000B`),
+form feed (`U+000C`), or carriage return (`U+000D`).
+
+[Whitespace](@) is a sequence of one or more [whitespace
+characters].
+
+A [Unicode whitespace character](@) is
+any code point in the Unicode `Zs` general category, or a tab (`U+0009`),
+carriage return (`U+000D`), newline (`U+000A`), or form feed
+(`U+000C`).
+
+[Unicode whitespace](@) is a sequence of one
+or more [Unicode whitespace characters].
+
+A [space](@) is `U+0020`.
+
+A [non-whitespace character](@) is any character
+that is not a [whitespace character].
+
+An [ASCII punctuation character](@)
+is `!`, `"`, `#`, `$`, `%`, `&`, `'`, `(`, `)`,
+`*`, `+`, `,`, `-`, `.`, `/` (U+0021–2F),
+`:`, `;`, `<`, `=`, `>`, `?`, `@` (U+003A–0040),
+`[`, `\`, `]`, `^`, `_`, `` ` `` (U+005B–0060),
+`{`, `|`, `}`, or `~` (U+007B–007E).
+
+A [punctuation character](@) is an [ASCII
+punctuation character] or anything in
+the general Unicode categories `Pc`, `Pd`, `Pe`, `Pf`, `Pi`, `Po`, or `Ps`.
+
+## Tabs
+
+Tabs in lines are not expanded to [spaces]. However,
+in contexts where whitespace helps to define block structure,
+tabs behave as if they were replaced by spaces with a tab stop
+of 4 characters.
+
+Thus, for example, a tab can be used instead of four spaces
+in an indented code block. (Note, however, that internal
+tabs are passed through as literal tabs, not expanded to
+spaces.)
+
+```````````````````````````````` example
+→foo→baz→→bim
+.
+<pre><code>foo→baz→→bim
+</code></pre>
+````````````````````````````````
+
+```````````````````````````````` example
+ →foo→baz→→bim
+.
+<pre><code>foo→baz→→bim
+</code></pre>
+````````````````````````````````
+
+```````````````````````````````` example
+ a→a
+ ὐ→a
+.
+<pre><code>a→a
+ὐ→a
+</code></pre>
+````````````````````````````````
+
+In the following example, a continuation paragraph of a list
+item is indented with a tab; this has exactly the same effect
+as indentation with four spaces would:
+
+```````````````````````````````` example
+ - foo
+
+→bar
+.
+<ul>
+<li>
+<p>foo</p>
+<p>bar</p>
+</li>
+</ul>
+````````````````````````````````
+
+```````````````````````````````` example
+- foo
+
+→→bar
+.
+<ul>
+<li>
+<p>foo</p>
+<pre><code> bar
+</code></pre>
+</li>
+</ul>
+````````````````````````````````
+
+Normally the `>` that begins a block quote may be followed
+optionally by a space, which is not considered part of the
+content. In the following case `>` is followed by a tab,
+which is treated as if it were expanded into three spaces.
+Since one of these spaces is considered part of the
+delimiter, `foo` is considered to be indented six spaces
+inside the block quote context, so we get an indented
+code block starting with two spaces.
+
+```````````````````````````````` example
+>→→foo
+.
+<blockquote>
+<pre><code> foo
+</code></pre>
+</blockquote>
+````````````````````````````````
+
+```````````````````````````````` example
+-→→foo
+.
+<ul>
+<li>
+<pre><code> foo
+</code></pre>
+</li>
+</ul>
+````````````````````````````````
+
+
+```````````````````````````````` example
+ foo
+→bar
+.
+<pre><code>foo
+bar
+</code></pre>
+````````````````````````````````
+
+```````````````````````````````` example
+ - foo
+ - bar
+→ - baz
+.
+<ul>
+<li>foo
+<ul>
+<li>bar
+<ul>
+<li>baz</li>
+</ul>
+</li>
+</ul>
+</li>
+</ul>
+````````````````````````````````
+
+```````````````````````````````` example
+#→Foo
+.
+<h1>Foo</h1>
+````````````````````````````````
+
+```````````````````````````````` example
+*→*→*→
+.
+<hr />
+````````````````````````````````
+
+
+## Insecure characters
+
+For security reasons, the Unicode character `U+0000` must be replaced
+with the REPLACEMENT CHARACTER (`U+FFFD`).
+
+# Blocks and inlines
+
+We can think of a document as a sequence of
+[blocks](@)---structural elements like paragraphs, block
+quotations, lists, headings, rules, and code blocks. Some blocks (like
+block quotes and list items) contain other blocks; others (like
+headings and paragraphs) contain [inline](@) content---text,
+links, emphasized text, images, code spans, and so on.
+
+## Precedence
+
+Indicators of block structure always take precedence over indicators
+of inline structure. So, for example, the following is a list with
+two items, not a list with one item containing a code span:
+
+```````````````````````````````` example
+- `one
+- two`
+.
+<ul>
+<li>`one</li>
+<li>two`</li>
+</ul>
+````````````````````````````````
+
+
+This means that parsing can proceed in two steps: first, the block
+structure of the document can be discerned; second, text lines inside
+paragraphs, headings, and other block constructs can be parsed for inline
+structure. The second step requires information about link reference
+definitions that will be available only at the end of the first
+step. Note that the first step requires processing lines in sequence,
+but the second can be parallelized, since the inline parsing of
+one block element does not affect the inline parsing of any other.
+
+## Container blocks and leaf blocks
+
+We can divide blocks into two types:
+[container blocks](@),
+which can contain other blocks, and [leaf blocks](@),
+which cannot.
+
+# Leaf blocks
+
+This section describes the different kinds of leaf block that make up a
+Markdown document.
+
+## Thematic breaks
+
+A line consisting of 0-3 spaces of indentation, followed by a sequence
+of three or more matching `-`, `_`, or `*` characters, each followed
+optionally by any number of spaces or tabs, forms a
+[thematic break](@).
+
+```````````````````````````````` example
+***
+---
+___
+.
+<hr />
+<hr />
+<hr />
+````````````````````````````````
+
+
+Wrong characters:
+
+```````````````````````````````` example
++++
+.
+<p>+++</p>
+````````````````````````````````
+
+
+```````````````````````````````` example
+===
+.
+<p>===</p>
+````````````````````````````````
+
+
+Not enough characters:
+
+```````````````````````````````` example
+--
+**
+__
+.
+<p>--
+**
+__</p>
+````````````````````````````````
+
+
+One to three spaces indent are allowed:
+
+```````````````````````````````` example
+ ***
+ ***
+ ***
+.
+<hr />
+<hr />
+<hr />
+````````````````````````````````
+
+
+Four spaces is too many:
+
+```````````````````````````````` example
+ ***
+.
+<pre><code>***
+</code></pre>
+````````````````````````````````
+
+
+```````````````````````````````` example
+Foo
+ ***
+.
+<p>Foo
+***</p>
+````````````````````````````````
+
+
+More than three characters may be used:
+
+```````````````````````````````` example
+_____________________________________
+.
+<hr />
+````````````````````````````````
+
+
+Spaces are allowed between the characters:
+
+```````````````````````````````` example
+ - - -
+.
+<hr />
+````````````````````````````````
+
+
+```````````````````````````````` example
+ ** * ** * ** * **
+.
+<hr />
+````````````````````````````````
+
+
+```````````````````````````````` example
+- - - -
+.
+<hr />
+````````````````````````````````
+
+
+Spaces are allowed at the end:
+
+```````````````````````````````` example
+- - - -
+.
+<hr />
+````````````````````````````````
+
+
+However, no other characters may occur in the line:
+
+```````````````````````````````` example
+_ _ _ _ a
+
+a------
+
+---a---
+.
+<p>_ _ _ _ a</p>
+<p>a------</p>
+<p>---a---</p>
+````````````````````````````````
+
+
+It is required that all of the [non-whitespace characters] be the same.
+So, this is not a thematic break:
+
+```````````````````````````````` example
+ *-*
+.
+<p><em>-</em></p>
+````````````````````````````````
+
+
+Thematic breaks do not need blank lines before or after:
+
+```````````````````````````````` example
+- foo
+***
+- bar
+.
+<ul>
+<li>foo</li>
+</ul>
+<hr />
+<ul>
+<li>bar</li>
+</ul>
+````````````````````````````````
+
+
+Thematic breaks can interrupt a paragraph:
+
+```````````````````````````````` example
+Foo
+***
+bar
+.
+<p>Foo</p>
+<hr />
+<p>bar</p>
+````````````````````````````````
+
+
+If a line of dashes that meets the above conditions for being a
+thematic break could also be interpreted as the underline of a [setext
+heading], the interpretation as a
+[setext heading] takes precedence. Thus, for example,
+this is a setext heading, not a paragraph followed by a thematic break:
+
+```````````````````````````````` example
+Foo
+---
+bar
+.
+<h2>Foo</h2>
+<p>bar</p>
+````````````````````````````````
+
+
+When both a thematic break and a list item are possible
+interpretations of a line, the thematic break takes precedence:
+
+```````````````````````````````` example
+* Foo
+* * *
+* Bar
+.
+<ul>
+<li>Foo</li>
+</ul>
+<hr />
+<ul>
+<li>Bar</li>
+</ul>
+````````````````````````````````
+
+
+If you want a thematic break in a list item, use a different bullet:
+
+```````````````````````````````` example
+- Foo
+- * * *
+.
+<ul>
+<li>Foo</li>
+<li>
+<hr />
+</li>
+</ul>
+````````````````````````````````
+
+
+## ATX headings
+
+An [ATX heading](@)
+consists of a string of characters, parsed as inline content, between an
+opening sequence of 1--6 unescaped `#` characters and an optional
+closing sequence of any number of unescaped `#` characters.
+The opening sequence of `#` characters must be followed by a
+[space] or by the end of line. The optional closing sequence of `#`s must be
+preceded by a [space] and may be followed by spaces only. The opening
+`#` character may be indented 0-3 spaces. The raw contents of the
+heading are stripped of leading and trailing spaces before being parsed
+as inline content. The heading level is equal to the number of `#`
+characters in the opening sequence.
+
+Simple headings:
+
+```````````````````````````````` example
+# foo
+## foo
+### foo
+#### foo
+##### foo
+###### foo
+.
+<h1>foo</h1>
+<h2>foo</h2>
+<h3>foo</h3>
+<h4>foo</h4>
+<h5>foo</h5>
+<h6>foo</h6>
+````````````````````````````````
+
+
+More than six `#` characters is not a heading:
+
+```````````````````````````````` example
+####### foo
+.
+<p>####### foo</p>
+````````````````````````````````
+
+
+At least one space is required between the `#` characters and the
+heading's contents, unless the heading is empty. Note that many
+implementations currently do not require the space. However, the
+space was required by the
+[original ATX implementation](http://www.aaronsw.com/2002/atx/atx.py),
+and it helps prevent things like the following from being parsed as
+headings:
+
+```````````````````````````````` example
+#5 bolt
+
+#hashtag
+.
+<p>#5 bolt</p>
+<p>#hashtag</p>
+````````````````````````````````
+
+
+This is not a heading, because the first `#` is escaped:
+
+```````````````````````````````` example
+\## foo
+.
+<p>## foo</p>
+````````````````````````````````
+
+
+Contents are parsed as inlines:
+
+```````````````````````````````` example
+# foo *bar* \*baz\*
+.
+<h1>foo <em>bar</em> *baz*</h1>
+````````````````````````````````
+
+
+Leading and trailing [whitespace] is ignored in parsing inline content:
+
+```````````````````````````````` example
+# foo
+.
+<h1>foo</h1>
+````````````````````````````````
+
+
+One to three spaces indentation are allowed:
+
+```````````````````````````````` example
+ ### foo
+ ## foo
+ # foo
+.
+<h3>foo</h3>
+<h2>foo</h2>
+<h1>foo</h1>
+````````````````````````````````
+
+
+Four spaces are too much:
+
+```````````````````````````````` example
+ # foo
+.
+<pre><code># foo
+</code></pre>
+````````````````````````````````
+
+
+```````````````````````````````` example
+foo
+ # bar
+.
+<p>foo
+# bar</p>
+````````````````````````````````
+
+
+A closing sequence of `#` characters is optional:
+
+```````````````````````````````` example
+## foo ##
+ ### bar ###
+.
+<h2>foo</h2>
+<h3>bar</h3>
+````````````````````````````````
+
+
+It need not be the same length as the opening sequence:
+
+```````````````````````````````` example
+# foo ##################################
+##### foo ##
+.
+<h1>foo</h1>
+<h5>foo</h5>
+````````````````````````````````
+
+
+Spaces are allowed after the closing sequence:
+
+```````````````````````````````` example
+### foo ###
+.
+<h3>foo</h3>
+````````````````````````````````
+
+
+A sequence of `#` characters with anything but [spaces] following it
+is not a closing sequence, but counts as part of the contents of the
+heading:
+
+```````````````````````````````` example
+### foo ### b
+.
+<h3>foo ### b</h3>
+````````````````````````````````
+
+
+The closing sequence must be preceded by a space:
+
+```````````````````````````````` example
+# foo#
+.
+<h1>foo#</h1>
+````````````````````````````````
+
+
+Backslash-escaped `#` characters do not count as part
+of the closing sequence:
+
+```````````````````````````````` example
+### foo \###
+## foo #\##
+# foo \#
+.
+<h3>foo ###</h3>
+<h2>foo ###</h2>
+<h1>foo #</h1>
+````````````````````````````````
+
+
+ATX headings need not be separated from surrounding content by blank
+lines, and they can interrupt paragraphs:
+
+```````````````````````````````` example
+****
+## foo
+****
+.
+<hr />
+<h2>foo</h2>
+<hr />
+````````````````````````````````
+
+
+```````````````````````````````` example
+Foo bar
+# baz
+Bar foo
+.
+<p>Foo bar</p>
+<h1>baz</h1>
+<p>Bar foo</p>
+````````````````````````````````
+
+
+ATX headings can be empty:
+
+```````````````````````````````` example
+##
+#
+### ###
+.
+<h2></h2>
+<h1></h1>
+<h3></h3>
+````````````````````````````````
+
+
+## Setext headings
+
+A [setext heading](@) consists of one or more
+lines of text, each containing at least one [non-whitespace
+character], with no more than 3 spaces indentation, followed by
+a [setext heading underline]. The lines of text must be such
+that, were they not followed by the setext heading underline,
+they would be interpreted as a paragraph: they cannot be
+interpretable as a [code fence], [ATX heading][ATX headings],
+[block quote][block quotes], [thematic break][thematic breaks],
+[list item][list items], or [HTML block][HTML blocks].
+
+A [setext heading underline](@) is a sequence of
+`=` characters or a sequence of `-` characters, with no more than 3
+spaces indentation and any number of trailing spaces. If a line
+containing a single `-` can be interpreted as an
+empty [list items], it should be interpreted this way
+and not as a [setext heading underline].
+
+The heading is a level 1 heading if `=` characters are used in
+the [setext heading underline], and a level 2 heading if `-`
+characters are used. The contents of the heading are the result
+of parsing the preceding lines of text as CommonMark inline
+content.
+
+In general, a setext heading need not be preceded or followed by a
+blank line. However, it cannot interrupt a paragraph, so when a
+setext heading comes after a paragraph, a blank line is needed between
+them.
+
+Simple examples:
+
+```````````````````````````````` example
+Foo *bar*
+=========
+
+Foo *bar*
+---------
+.
+<h1>Foo <em>bar</em></h1>
+<h2>Foo <em>bar</em></h2>
+````````````````````````````````
+
+
+The content of the header may span more than one line:
+
+```````````````````````````````` example
+Foo *bar
+baz*
+====
+.
+<h1>Foo <em>bar
+baz</em></h1>
+````````````````````````````````
+
+The contents are the result of parsing the headings's raw
+content as inlines. The heading's raw content is formed by
+concatenating the lines and removing initial a