();
string backslashPattern = "";
foreach (char c in @"\`*_{}[]()>#+-.!/")
{
string key = c.ToString();
string hash = GetHashKey(key, isHtmlBlock: false);
_escapeTable.Add(key, hash);
_invertedEscapeTable.Add(hash, key);
_backslashEscapeTable.Add(@"\" + key, hash);
backslashPattern += Regex.Escape(@"\" + key) + "|";
}
_backslashEscapes = new Regex(backslashPattern.Substring(0, backslashPattern.Length - 1), RegexOptions.Compiled);
}
///
/// current version of MarkdownSharp;
/// see http://code.google.com/p/markdownsharp/ for the latest code or to contribute
///
public string Version
{
get { return _version; }
}
///
/// Transforms the provided Markdown-formatted text to HTML;
/// see http://en.wikipedia.org/wiki/Markdown
///
///
/// The order in which other subs are called here is
/// essential. Link and image substitutions need to happen before
/// EscapeSpecialChars(), so that any *'s or _'s in the a
/// and img tags get encoded.
///
public string Transform(string text)
{
if (String.IsNullOrEmpty(text)) return "";
Setup();
text = Normalize(text);
text = HashHTMLBlocks(text);
text = StripLinkDefinitions(text);
text = RunBlockGamut(text);
text = Unescape(text);
Cleanup();
return text + "\n";
}
///
/// Perform transformations that form block-level tags like paragraphs, headers, and list items.
///
private string RunBlockGamut(string text, bool unhash = true)
{
text = DoHeaders(text);
text = DoHorizontalRules(text);
text = DoLists(text);
text = DoCodeBlocks(text);
text = DoBlockQuotes(text);
// We already ran HashHTMLBlocks() before, in Markdown(), but that
// was to escape raw HTML in the original Markdown source. This time,
// we're escaping the markup we've just created, so that we don't wrap
// tags around block-level tags.
text = HashHTMLBlocks(text);
text = FormParagraphs(text, unhash: unhash);
return text;
}
///
/// Perform transformations that occur *within* block-level tags like paragraphs, headers, and list items.
///
private string RunSpanGamut(string text)
{
text = DoCodeSpans(text);
text = EscapeSpecialCharsWithinTagAttributes(text);
text = EscapeBackslashes(text);
// Images must come first, because ![foo][f] looks like an anchor.
text = DoImages(text);
text = DoAnchors(text);
// Must come after DoAnchors(), because you can use < and >
// delimiters in inline links like [this]().
text = DoAutoLinks(text);
text = text.Replace(AutoLinkPreventionMarker, "://");
text = EncodeAmpsAndAngles(text);
text = DoItalicsAndBold(text);
text = DoHardBreaks(text);
return text;
}
private static Regex _newlinesLeadingTrailing = new Regex(@"^\n+|\n+\z", RegexOptions.Compiled);
private static Regex _newlinesMultiple = new Regex(@"\n{2,}", RegexOptions.Compiled);
private static Regex _leadingWhitespace = new Regex(@"^[ ]*", RegexOptions.Compiled);
private static Regex _htmlBlockHash = new Regex("\x1AH\\d+H", RegexOptions.Compiled);
///
/// splits on two or more newlines, to form "paragraphs";
/// each paragraph is then unhashed (if it is a hash and unhashing isn't turned off) or wrapped in HTML p tag
///
private string FormParagraphs(string text, bool unhash = true)
{
// split on two or more newlines
string[] grafs = _newlinesMultiple.Split(_newlinesLeadingTrailing.Replace(text, ""));
for (int i = 0; i < grafs.Length; i++)
{
if (grafs[i].StartsWith("\x1AH"))
{
// unhashify HTML blocks
if (unhash)
{
int sanityCheck = 50; // just for safety, guard against an infinite loop
bool keepGoing = true; // as long as replacements where made, keep going
while (keepGoing && sanityCheck > 0)
{
keepGoing = false;
grafs[i] = _htmlBlockHash.Replace(grafs[i], match =>
{
keepGoing = true;
return _htmlBlocks[match.Value];
});
sanityCheck--;
}
/* if (keepGoing)
{
// Logging of an infinite loop goes here.
// If such a thing should happen, please open a new issue on http://code.google.com/p/markdownsharp/
// with the input that caused it.
}*/
}
}
else
{
// do span level processing inside the block, then wrap result in tags
grafs[i] = _leadingWhitespace.Replace(RunSpanGamut(grafs[i]), "
") + "
";
}
}
return string.Join("\n\n", grafs);
}
private void Setup()
{
// Clear the global hashes. If we don't clear these, you get conflicts
// from other articles when generating a page which contains more than
// one article (e.g. an index page that shows the N most recent
// articles):
_urls.Clear();
_titles.Clear();
_htmlBlocks.Clear();
_listLevel = 0;
}
private void Cleanup()
{
Setup();
}
private static string _nestedBracketsPattern;
///
/// Reusable pattern to match balanced [brackets]. See Friedl's
/// "Mastering Regular Expressions", 2nd Ed., pp. 328-331.
///
private static string GetNestedBracketsPattern()
{
// in other words [this] and [this[also]] and [this[also[too]]]
// up to _nestDepth
if (_nestedBracketsPattern == null)
_nestedBracketsPattern =
RepeatString(@"
(?> # Atomic matching
[^\[\]]+ # Anything other than brackets
|
\[
", _nestDepth) + RepeatString(
@" \]
)*"
, _nestDepth);
return _nestedBracketsPattern;
}
private static string _nestedParensPattern;
///
/// Reusable pattern to match balanced (parens). See Friedl's
/// "Mastering Regular Expressions", 2nd Ed., pp. 328-331.
///
private static string GetNestedParensPattern()
{
// in other words (this) and (this(also)) and (this(also(too)))
// up to _nestDepth
if (_nestedParensPattern == null)
_nestedParensPattern =
RepeatString(@"
(?> # Atomic matching
[^()\s]+ # Anything other than parens or whitespace
|
\(
", _nestDepth) + RepeatString(
@" \)
)*"
, _nestDepth);
return _nestedParensPattern;
}
private static Regex _linkDef = new Regex(string.Format(@"
^[ ]{{0,{0}}}\[([^\[\]]+)\]: # id = $1
[ ]*
\n? # maybe *one* newline
[ ]*
? # url = $2
[ ]*
\n? # maybe one newline
[ ]*
(?:
(?<=\s) # lookbehind for whitespace
[""(]
(.+?) # title = $3
["")]
[ ]*
)? # title is optional
(?:\n+|\Z)", _tabWidth - 1), RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
///
/// Strips link definitions from text, stores the URLs and titles in hash references.
///
///
/// ^[id]: url "optional title"
///
private string StripLinkDefinitions(string text)
{
return _linkDef.Replace(text, new MatchEvaluator(LinkEvaluator));
}
private string LinkEvaluator(Match match)
{
string linkID = match.Groups[1].Value.ToLowerInvariant();
_urls[linkID] = EncodeAmpsAndAngles(match.Groups[2].Value);
if (match.Groups[3] != null && match.Groups[3].Length > 0)
_titles[linkID] = match.Groups[3].Value.Replace("\"", """);
return "";
}
// compiling this monster regex results in worse performance. trust me.
private static Regex _blocksHtml = new Regex(GetBlockPattern(), RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace);
///
/// derived pretty much verbatim from PHP Markdown
///
private static string GetBlockPattern()
{
// Hashify HTML blocks:
// We only want to do this for block-level HTML tags, such as headers,
// lists, and tables. That's because we still want to wrap s around
// "paragraphs" that are wrapped in non-block-level tags, such as anchors,
// phrase emphasis, and spans. The list of tags we're looking for is
// hard-coded:
//
// * List "a" is made of tags which can be both inline or block-level.
// These will be treated block-level when the start tag is alone on
// its line, otherwise they're not matched here and will be taken as
// inline later.
// * List "b" is made of tags which are always block-level;
//
string blockTagsA = "ins|del";
string blockTagsB = "p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|address|script|noscript|form|fieldset|iframe|math";
// Regular expression for the content of a block tag.
string attr = @"
(?> # optional tag attributes
\s # starts with whitespace
(?>
[^>""/]+ # text outside quotes
|
/+(?!>) # slash not followed by >
|
""[^""]*"" # text inside double quotes (tolerate >)
|
'[^']*' # text inside single quotes (tolerate >)
)*
)?
";
string content = RepeatString(@"
(?>
[^<]+ # content without tag
|
<\2 # nested opening tag
" + attr + @" # attributes
(?>
/>
|
>", _nestDepth) + // end of opening tag
".*?" + // last level nested tag content
RepeatString(@"
# closing nested tag
)
|
<(?!/\2\s*> # other tags with a different name
)
)*", _nestDepth);
string content2 = content.Replace(@"\2", @"\3");
// First, look for nested blocks, e.g.:
//
//
// tags for inner block must be indented.
//
//
` and stop at the first `
`.
string pattern = @"
(?>
(?>
(?<=\n) # Starting at the beginning of a line
| # or
\A\n? # the beginning of the doc
)
( # save in $1
# Match from `\n` to `\n`, handling nested tags
# in between.
<($block_tags_b_re) # start tag = $2
$attr> # attributes followed by > and \n
$content # content, support nesting
# the matching end tag
[ ]* # trailing spaces
(?=\n+|\Z) # followed by a newline or end of document
| # Special version for tags of group a.
<($block_tags_a_re) # start tag = $3
$attr>[ ]*\n # attributes followed by >
$content2 # content, support nesting
# the matching end tag
[ ]* # trailing spaces
(?=\n+|\Z) # followed by a newline or end of document
| # Special case just for
. It was easier to make a special
# case than to make the other regex more complicated.
[ ]{0,$less_than_tab}
# the matching end tag
[ ]*
(?=\n{2,}|\Z) # followed by a blank line or end of document
| # Special case for standalone HTML comments:
(?<=\n\n|\A) # preceded by a blank line or start of document
[ ]{0,$less_than_tab}
(?s:
)
[ ]*
(?=\n{2,}|\Z) # followed by a blank line or end of document
| # PHP and ASP-style processor instructions (
)
[ ]*
(?=\n{2,}|\Z) # followed by a blank line or end of document
)
)";
pattern = pattern.Replace("$less_than_tab", (_tabWidth - 1).ToString());
pattern = pattern.Replace("$block_tags_b_re", blockTagsB);
pattern = pattern.Replace("$block_tags_a_re", blockTagsA);
pattern = pattern.Replace("$attr", attr);
pattern = pattern.Replace("$content2", content2);
pattern = pattern.Replace("$content", content);
return pattern;
}
///
/// replaces any block-level HTML blocks with hash entries
///
private string HashHTMLBlocks(string text)
{
return _blocksHtml.Replace(text, new MatchEvaluator(HtmlEvaluator));
}
private string HtmlEvaluator(Match match)
{
string text = match.Groups[1].Value;
string key = GetHashKey(text, isHtmlBlock: true);
_htmlBlocks[key] = text;
return string.Concat("\n\n", key, "\n\n");
}
private static string GetHashKey(string s, bool isHtmlBlock)
{
var delim = isHtmlBlock ? 'H' : 'E';
return "\x1A" + delim + Math.Abs(s.GetHashCode()).ToString() + delim;
}
private static Regex _htmlTokens = new Regex(@"
()| # match
(<\?.*?\?>)| # match " +
RepeatString(@"
(<[A-Za-z\/!$](?:[^<>]|", _nestDepth) + RepeatString(@")*>)", _nestDepth) +
" # match and ",
RegexOptions.Multiline | RegexOptions.Singleline | RegexOptions.ExplicitCapture | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
///
/// returns an array of HTML tokens comprising the input string. Each token is
/// either a tag (possibly with nested, tags contained therein, such
/// as <a href="<MTFoo>">, or a run of text between tags. Each element of the
/// array is a two-element array; the first is either 'tag' or 'text'; the second is
/// the actual value.
///
private List TokenizeHTML(string text)
{
int pos = 0;
int tagStart = 0;
var tokens = new List();
// this regex is derived from the _tokenize() subroutine in Brad Choate's MTRegex plugin.
// http://www.bradchoate.com/past/mtregex.php
foreach (Match m in _htmlTokens.Matches(text))
{
tagStart = m.Index;
if (pos < tagStart)
tokens.Add(new Token(TokenType.Text, text.Substring(pos, tagStart - pos)));
tokens.Add(new Token(TokenType.Tag, m.Value));
pos = tagStart + m.Length;
}
if (pos < text.Length)
tokens.Add(new Token(TokenType.Text, text.Substring(pos, text.Length - pos)));
return tokens;
}
private static Regex _anchorRef = new Regex(string.Format(@"
( # wrap whole match in $1
\[
({0}) # link text = $2
\]
[ ]? # one optional space
(?:\n[ ]*)? # one optional newline followed by spaces
\[
(.*?) # id = $3
\]
)", GetNestedBracketsPattern()), RegexOptions.Singleline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
private static Regex _anchorInline = new Regex(string.Format(@"
( # wrap whole match in $1
\[
({0}) # link text = $2
\]
\( # literal paren
[ ]*
({1}) # href = $3
[ ]*
( # $4
(['""]) # quote char = $5
(.*?) # title = $6
\5 # matching quote
[ ]* # ignore any spaces between closing quote and )
)? # title is optional
\)
)", GetNestedBracketsPattern(), GetNestedParensPattern()),
RegexOptions.Singleline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
private static Regex _anchorRefShortcut = new Regex(@"
( # wrap whole match in $1
\[
([^\[\]]+) # link text = $2; can't contain [ or ]
\]
)", RegexOptions.Singleline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
///
/// Turn Markdown link shortcuts into HTML anchor tags
///
///
/// [link text](url "title")
/// [link text][id]
/// [id]
///
private string DoAnchors(string text)
{
// First, handle reference-style links: [link text] [id]
text = _anchorRef.Replace(text, new MatchEvaluator(AnchorRefEvaluator));
// Next, inline-style links: [link text](url "optional title") or [link text](url "optional title")
text = _anchorInline.Replace(text, new MatchEvaluator(AnchorInlineEvaluator));
// Last, handle reference-style shortcuts: [link text]
// These must come last in case you've also got [link test][1]
// or [link test](/foo)
text = _anchorRefShortcut.Replace(text, new MatchEvaluator(AnchorRefShortcutEvaluator));
return text;
}
private string SaveFromAutoLinking(string s)
{
return s.Replace("://", AutoLinkPreventionMarker);
}
private string AnchorRefEvaluator(Match match)
{
string wholeMatch = match.Groups[1].Value;
string linkText = SaveFromAutoLinking(match.Groups[2].Value);
string linkID = match.Groups[3].Value.ToLowerInvariant();
string result;
// for shortcut links like [this][].
if (linkID == "")
linkID = linkText.ToLowerInvariant();
if (_urls.ContainsKey(linkID))
{
string url = _urls[linkID];
url = EncodeProblemUrlChars(url);
url = EscapeBoldItalic(url);
result = "";
}
else
result = wholeMatch;
return result;
}
private string AnchorRefShortcutEvaluator(Match match)
{
string wholeMatch = match.Groups[1].Value;
string linkText = SaveFromAutoLinking(match.Groups[2].Value);
string linkID = Regex.Replace(linkText.ToLowerInvariant(), @"[ ]*\n[ ]*", " "); // lower case and remove newlines / extra spaces
string result;
if (_urls.ContainsKey(linkID))
{
string url = _urls[linkID];
url = EncodeProblemUrlChars(url);
url = EscapeBoldItalic(url);
result = "";
}
else
result = wholeMatch;
return result;
}
private string AnchorInlineEvaluator(Match match)
{
string linkText = SaveFromAutoLinking(match.Groups[2].Value);
string url = match.Groups[3].Value;
string title = match.Groups[6].Value;
string result;
url = EncodeProblemUrlChars(url);
url = EscapeBoldItalic(url);
if (url.StartsWith("<") && url.EndsWith(">"))
url = url.Substring(1, url.Length - 2); // remove <>'s surrounding URL, if present
result = string.Format("{0}", linkText);
return result;
}
private static Regex _imagesRef = new Regex(@"
( # wrap whole match in $1
!\[
(.*?) # alt text = $2
\]
[ ]? # one optional space
(?:\n[ ]*)? # one optional newline followed by spaces
\[
(.*?) # id = $3
\]
)", RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline | RegexOptions.Compiled);
private static Regex _imagesInline = new Regex(String.Format(@"
( # wrap whole match in $1
!\[
(.*?) # alt text = $2
\]
\s? # one optional whitespace character
\( # literal paren
[ ]*
({0}) # href = $3
[ ]*
( # $4
(['""]) # quote char = $5
(.*?) # title = $6
\5 # matching quote
[ ]*
)? # title is optional
\)
)", GetNestedParensPattern()),
RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline | RegexOptions.Compiled);
///
/// Turn Markdown image shortcuts into HTML img tags.
///
///
/// ![alt text][id]
/// 
///
private string DoImages(string text)
{
// First, handle reference-style labeled images: ![alt text][id]
text = _imagesRef.Replace(text, new MatchEvaluator(ImageReferenceEvaluator));
// Next, handle inline images: 
// Don't forget: encode * and _
text = _imagesInline.Replace(text, new MatchEvaluator(ImageInlineEvaluator));
return text;
}
// This prevents the creation of horribly broken HTML when some syntax ambiguities
// collide. It likely still doesn't do what the user meant, but at least we're not
// outputting garbage.
private string EscapeImageAltText(string s)
{
s = EscapeBoldItalic(s);
s = Regex.Replace(s, @"[\[\]()]", m => _escapeTable[m.ToString()]);
return s;
}
private string ImageReferenceEvaluator(Match match)
{
string wholeMatch = match.Groups[1].Value;
string altText = match.Groups[2].Value;
string linkID = match.Groups[3].Value.ToLowerInvariant();
// for shortcut links like ![this][].
if (linkID == "")
linkID = altText.ToLowerInvariant();
if (_urls.ContainsKey(linkID))
{
string url = _urls[linkID];
string title = null;
if (_titles.ContainsKey(linkID))
title = _titles[linkID];
return ImageTag(url, altText, title);
}
else
{
// If there's no such link ID, leave intact:
return wholeMatch;
}
}
private string ImageInlineEvaluator(Match match)
{
string alt = match.Groups[2].Value;
string url = match.Groups[3].Value;
string title = match.Groups[6].Value;
if (url.StartsWith("<") && url.EndsWith(">"))
url = url.Substring(1, url.Length - 2); // Remove <>'s surrounding URL, if present
return ImageTag(url, alt, title);
}
private string ImageTag(string url, string altText, string title)
{
altText = EscapeImageAltText(AttributeEncode(altText));
url = EncodeProblemUrlChars(url);
url = EscapeBoldItalic(url);
var result = string.Format("![\"{1}\"",](\"{0}\" "AttributeEncode(EscapeBoldItalic(title));")
/// Turn Markdown headers into HTML header tags
///
///
/// Header 1
/// ========
///
/// Header 2
/// --------
///
/// # Header 1
/// ## Header 2
/// ## Header 2 with closing hashes ##
/// ...
/// ###### Header 6
///
private string DoHeaders(string text)
{
text = _headerSetext.Replace(text, new MatchEvaluator(SetextHeaderEvaluator));
text = _headerAtx.Replace(text, new MatchEvaluator(AtxHeaderEvaluator));
return text;
}
private string SetextHeaderEvaluator(Match match)
{
string header = match.Groups[1].Value;
int level = match.Groups[2].Value.StartsWith("=") ? 1 : 2;
return string.Format("{0}\n\n", RunSpanGamut(header), level);
}
private string AtxHeaderEvaluator(Match match)
{
string header = match.Groups[2].Value;
int level = match.Groups[1].Value.Length;
return string.Format("{0}\n\n", RunSpanGamut(header), level);
}
private static Regex _horizontalRules = new Regex(@"
^[ ]{0,3} # Leading space
([-*_]) # $1: First marker
(?> # Repeated marker group
[ ]{0,2} # Zero, one, or two spaces.
\1 # Marker character
){2,} # Group repeated at least twice
[ ]* # Trailing spaces
$ # End of line.
", RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
///
/// Turn Markdown horizontal rules into HTML hr tags
///
///
/// ***
/// * * *
/// ---
/// - - -
///
private string DoHorizontalRules(string text)
{
return _horizontalRules.Replace(text, "
/// Turn Markdown lists into HTML ul and ol and li tags
///
private string DoLists(string text, bool isInsideParagraphlessListItem = false)
{
// We use a different prefix before nested lists than top-level lists.
// See extended comment in _ProcessListItems().
if (_listLevel > 0)
text = _listNested.Replace(text, GetListEvaluator(isInsideParagraphlessListItem));
else
text = _listTopLevel.Replace(text, GetListEvaluator(false));
return text;
}
private MatchEvaluator GetListEvaluator(bool isInsideParagraphlessListItem = false)
{
return new MatchEvaluator(match =>
{
string list = match.Groups[1].Value;
string listType = Regex.IsMatch(match.Groups[3].Value, _markerUL) ? "ul" : "ol";
string result;
result = ProcessListItems(list, listType == "ul" ? _markerUL : _markerOL, isInsideParagraphlessListItem);
result = string.Format("<{0}>\n{1}\n", listType, result);
return result;
});
}
///
/// Process the contents of a single ordered or unordered list, splitting it
/// into individual list items.
///
private string ProcessListItems(string list, string marker, bool isInsideParagraphlessListItem = false)
{
// The listLevel global keeps track of when we're inside a list.
// Each time we enter a list, we increment it; when we leave a list,
// we decrement. If it's zero, we're not in a list anymore.
// We do this because when we're not inside a list, we want to treat
// something like this:
// I recommend upgrading to version
// 8. Oops, now this line is treated
// as a sub-list.
// As a single paragraph, despite the fact that the second line starts
// with a digit-period-space sequence.
// Whereas when we're inside a list (or sub-list), that line will be
// treated as the start of a sub-list. What a kludge, huh? This is
// an aspect of Markdown's syntax that's hard to parse perfectly
// without resorting to mind-reading. Perhaps the solution is to
// change the syntax rules such that sub-lists must start with a
// starting cardinal number; e.g. "1." or "a.".
_listLevel++;
// Trim trailing blank lines:
list = Regex.Replace(list, @"\n{2,}\z", "\n");
string pattern = string.Format(
@"(^[ ]*) # leading whitespace = $1
({0}) [ ]+ # list marker = $2
((?s:.+?) # list item text = $3
(\n+))
(?= (\z | \1 ({0}) [ ]+))", marker);
bool lastItemHadADoubleNewline = false;
// has to be a closure, so subsequent invocations can share the bool
MatchEvaluator ListItemEvaluator = (Match match) =>
{
string item = match.Groups[3].Value;
bool endsWithDoubleNewline = item.EndsWith("\n\n");
bool containsDoubleNewline = endsWithDoubleNewline || item.Contains("\n\n");
if (containsDoubleNewline || lastItemHadADoubleNewline)
// we could correct any bad indentation here..
item = RunBlockGamut(Outdent(item) + "\n", unhash: false);
else
{
// recursion for sub-lists
item = DoLists(Outdent(item), isInsideParagraphlessListItem: true);
item = item.TrimEnd('\n');
if (!isInsideParagraphlessListItem) // only the outer-most item should run this, otherwise it's run multiple times for the inner ones
item = RunSpanGamut(item);
}
lastItemHadADoubleNewline = endsWithDoubleNewline;
return string.Format("{0}\n", item);
};
list = Regex.Replace(list, pattern, new MatchEvaluator(ListItemEvaluator),
RegexOptions.IgnorePatternWhitespace | RegexOptions.Multiline);
_listLevel--;
return list;
}
private static Regex _codeBlock = new Regex(string.Format(@"
(?:\n\n|\A\n?)
( # $1 = the code block -- one or more lines, starting with a space
(?:
(?:[ ]{{{0}}}) # Lines must start with a tab-width of spaces
.*\n+
)+
)
((?=^[ ]{{0,{0}}}[^ \t\n])|\Z) # Lookahead for non-space at line-start, or end of doc",
_tabWidth), RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
///
/// /// Turn Markdown 4-space indented code into HTML pre code blocks
///
private string DoCodeBlocks(string text)
{
text = _codeBlock.Replace(text, new MatchEvaluator(CodeBlockEvaluator));
return text;
}
private string CodeBlockEvaluator(Match match)
{
string codeBlock = match.Groups[1].Value;
codeBlock = EncodeCode(Outdent(codeBlock));
codeBlock = _newlinesLeadingTrailing.Replace(codeBlock, "");
return string.Concat("\n\n", codeBlock, "\n
\n\n");
}
private static Regex _codeSpan = new Regex(@"
(?
/// Turn Markdown `code spans` into HTML code tags
///
private string DoCodeSpans(string text)
{
// * You can use multiple backticks as the delimiters if you want to
// include literal backticks in the code span. So, this input:
//
// Just type ``foo `bar` baz`` at the prompt.
//
// Will translate to:
//
// Just type foo `bar` baz at the prompt.
//
// There's no arbitrary limit to the number of backticks you
// can use as delimters. If you need three consecutive backticks
// in your code, use four for delimiters, etc.
//
// * You can use spaces to get literal backticks at the edges:
//
// ... type `` `bar` `` ...
//
// Turns to:
//
// ... type `bar` ...
//
return _codeSpan.Replace(text, new MatchEvaluator(CodeSpanEvaluator));
}
private string CodeSpanEvaluator(Match match)
{
string span = match.Groups[2].Value;
span = Regex.Replace(span, @"^[ ]*", ""); // leading whitespace
span = Regex.Replace(span, @"[ ]*$", ""); // trailing whitespace
span = EncodeCode(span);
span = SaveFromAutoLinking(span); // to prevent auto-linking. Not necessary in code *blocks*, but in code spans.
return string.Concat("", span, "");
}
private static Regex _bold = new Regex(@"(\*\*|__) (?=\S) (.+?[*_]*) (?<=\S) \1",
RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline | RegexOptions.Compiled);
private static Regex _strictBold = new Regex(@"(^|[\W_])(?:(?!\1)|(?=^))(\*|_)\2(?=\S)(.*?\S)\2\2(?!\2)(?=[\W_]|$)",
RegexOptions.Singleline | RegexOptions.Compiled);
private static Regex _italic = new Regex(@"(\*|_) (?=\S) (.+?) (?<=\S) \1",
RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline | RegexOptions.Compiled);
private static Regex _strictItalic = new Regex(@"(^|[\W_])(?:(?!\1)|(?=^))(\*|_)(?=\S)((?:(?!\2).)*?\S)\2(?!\2)(?=[\W_]|$)",
RegexOptions.Singleline | RegexOptions.Compiled);
///
/// Turn Markdown *italics* and **bold** into HTML strong and em tags
///
private string DoItalicsAndBold(string text)
{
// must go first, then
if (_strictBoldItalic)
{
text = _strictBold.Replace(text, "$1$3");
text = _strictItalic.Replace(text, "$1$3");
}
else
{
text = _bold.Replace(text, "$2");
text = _italic.Replace(text, "$2");
}
return text;
}
///
/// Turn markdown line breaks (two space at end of line) into HTML break tags
///
private string DoHardBreaks(string text)
{
if (_autoNewlines)
text = Regex.Replace(text, @"\n", string.Format("[ ]? # '>' at the start of a line
.+\n # rest of the first line
(.+\n)* # subsequent consecutive lines
\n* # blanks
)+
)", RegexOptions.IgnorePatternWhitespace | RegexOptions.Multiline | RegexOptions.Compiled);
///
/// Turn Markdown > quoted blocks into HTML blockquote blocks
///
private string DoBlockQuotes(string text)
{
return _blockquote.Replace(text, new MatchEvaluator(BlockQuoteEvaluator));
}
private string BlockQuoteEvaluator(Match match)
{
string bq = match.Groups[1].Value;
bq = Regex.Replace(bq, @"^[ ]*>[ ]?", "", RegexOptions.Multiline); // trim one level of quoting
bq = Regex.Replace(bq, @"^[ ]+$", "", RegexOptions.Multiline); // trim whitespace-only lines
bq = RunBlockGamut(bq); // recurse
bq = Regex.Replace(bq, @"^", " ", RegexOptions.Multiline);
// These leading spaces screw with content, so we need to fix that:
bq = Regex.Replace(bq, @"(\s*.+?
)", new MatchEvaluator(BlockQuoteEvaluator2), RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline);
bq = string.Format("\n{0}\n
", bq);
string key = GetHashKey(bq, isHtmlBlock: true);
_htmlBlocks[key] = bq;
return "\n\n" + key + "\n\n";
}
private string BlockQuoteEvaluator2(Match match)
{
return Regex.Replace(match.Groups[1].Value, @"^ ", "", RegexOptions.Multiline);
}
private const string _charInsideUrl = @"[-A-Z0-9+&@#/%?=~_|\[\]\(\)!:,\.;" + "\x1a]";
private const string _charEndingUrl = "[-A-Z0-9+&@#/%=~_|\\[\\])]";
private static Regex _autolinkBare = new Regex(@"(<|="")?\b(https?|ftp)(://" + _charInsideUrl + "*" + _charEndingUrl + ")(?=$|\\W)",
RegexOptions.IgnoreCase | RegexOptions.Compiled);
private static Regex _endCharRegex = new Regex(_charEndingUrl, RegexOptions.IgnoreCase | RegexOptions.Compiled);
private static string handleTrailingParens(Match match)
{
// The first group is essentially a negative lookbehind -- if there's a < or a =", we don't touch this.
// We're not using a *real* lookbehind, because of links with in links, like
// With a real lookbehind, the full link would never be matched, and thus the http://www.google.com *would* be matched.
// With the simulated lookbehind, the full link *is* matched (just not handled, because of this early return), causing
// the google link to not be matched again.
if (match.Groups[1].Success)
return match.Value;
var protocol = match.Groups[2].Value;
var link = match.Groups[3].Value;
if (!link.EndsWith(")"))
return "<" + protocol + link + ">";
var level = 0;
foreach (Match c in Regex.Matches(link, "[()]"))
{
if (c.Value == "(")
{
if (level <= 0)
level = 1;
else
level++;
}
else
{
level--;
}
}
var tail = "";
if (level < 0)
{
link = Regex.Replace(link, @"\){1," + (-level) + "}$", m => { tail = m.Value; return ""; });
}
if (tail.Length > 0)
{
var lastChar = link[link.Length - 1];
if (!_endCharRegex.IsMatch(lastChar.ToString()))
{
tail = lastChar + tail;
link = link.Substring(0, link.Length - 1);
}
}
return "<" + protocol + link + ">" + tail;
}
///
/// Turn angle-delimited URLs into HTML anchor tags
///
///
/// <http://www.example.com>
///
private string DoAutoLinks(string text)
{
if (_autoHyperlink)
{
// fixup arbitrary URLs by adding Markdown < > so they get linked as well
// note that at this point, all other URL in the text are already hyperlinked as
// *except* for the case
text = _autolinkBare.Replace(text, handleTrailingParens);
}
// Hyperlinks:
text = Regex.Replace(text, "<((https?|ftp):[^'\">\\s]+)>", new MatchEvaluator(HyperlinkEvaluator));
if (_linkEmails)
{
// Email addresses:
string pattern =
@"<
(?:mailto:)?
(
[-.\w]+
\@
[-a-z0-9]+(\.[-a-z0-9]+)*\.[a-z]+
)
>";
text = Regex.Replace(text, pattern, new MatchEvaluator(EmailEvaluator), RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
}
return text;
}
private string HyperlinkEvaluator(Match match)
{
string link = match.Groups[1].Value;
return string.Format("{1}", EscapeBoldItalic(EncodeProblemUrlChars(link)), link);
}
private string EmailEvaluator(Match match)
{
string email = Unescape(match.Groups[1].Value);
//
// Input: an email address, e.g. "foo@example.com"
//
// Output: the email address as a mailto link, with each character
// of the address encoded as either a decimal or hex entity, in
// the hopes of foiling most address harvesting spam bots. E.g.:
//
// foo
// @example.com
//
// Based by a filter by Matthew Wickline, posted to the BBEdit-Talk
// mailing list:
//
email = "mailto:" + email;
// leave ':' alone (to spot mailto: later)
email = EncodeEmailAddress(email);
email = string.Format("{0}", email);
// strip the mailto: from the visible part
email = Regex.Replace(email, "\">.+?:", "\">");
return email;
}
private static Regex _outDent = new Regex(@"^[ ]{1," + _tabWidth + @"}", RegexOptions.Multiline | RegexOptions.Compiled);
///
/// Remove one level of line-leading spaces
///
private string Outdent(string block)
{
return _outDent.Replace(block, "");
}
#region Encoding and Normalization
///
/// encodes email address randomly
/// roughly 10% raw, 45% hex, 45% dec
/// note that @ is always encoded and : never is
///
private string EncodeEmailAddress(string addr)
{
var sb = new StringBuilder(addr.Length * 5);
var rand = new Random();
int r;
foreach (char c in addr)
{
r = rand.Next(1, 100);
if ((r > 90 || c == ':') && c != '@')
sb.Append(c); // m
else if (r < 45)
sb.AppendFormat("&#x{0:x};", (int)c); // m
else
sb.AppendFormat("&#{0};", (int)c); // m
}
return sb.ToString();
}
private static Regex _codeEncoder = new Regex(@"&|<|>|\\|\*|_|\{|\}|\[|\]", RegexOptions.Compiled);
///
/// Encode/escape certain Markdown characters inside code blocks and spans where they are literals
///
private string EncodeCode(string code)
{
return _codeEncoder.Replace(code, EncodeCodeEvaluator);
}
private string EncodeCodeEvaluator(Match match)
{
switch (match.Value)
{
// Encode all ampersands; HTML entities are not
// entities within a Markdown code span.
case "&":
return "&";
// Do the angle bracket song and dance
case "<":
return "<";
case ">":
return ">";
// escape characters that are magic in Markdown
default:
return _escapeTable[match.Value];
}
}
private static Regex _amps = new Regex(@"&(?!((#[0-9]+)|(#[xX][a-fA-F0-9]+)|([a-zA-Z][a-zA-Z0-9]*));)", RegexOptions.ExplicitCapture | RegexOptions.Compiled);
private static Regex _angles = new Regex(@"<(?![A-Za-z/?\$!])", RegexOptions.ExplicitCapture | RegexOptions.Compiled);
///
/// Encode any ampersands (that aren't part of an HTML entity) and left or right angle brackets
///
private string EncodeAmpsAndAngles(string s)
{
s = _amps.Replace(s, "&");
s = _angles.Replace(s, "<");
return s;
}
private static Regex _backslashEscapes;
///
/// Encodes any escaped characters such as \`, \*, \[ etc
///
private string EscapeBackslashes(string s)
{
return _backslashEscapes.Replace(s, new MatchEvaluator(EscapeBackslashesEvaluator));
}
private string EscapeBackslashesEvaluator(Match match)
{
return _backslashEscapeTable[match.Value];
}
private static Regex _unescapes = new Regex("\x1A" + "E\\d+E", RegexOptions.Compiled);
///
/// swap back in all the special characters we've hidden
///
private string Unescape(string s)
{
return _unescapes.Replace(s, new MatchEvaluator(UnescapeEvaluator));
}
private string UnescapeEvaluator(Match match)
{
return _invertedEscapeTable[match.Value];
}
///
/// escapes Bold [ * ] and Italic [ _ ] characters
///
private string EscapeBoldItalic(string s)
{
s = s.Replace("*", _escapeTable["*"]);
s = s.Replace("_", _escapeTable["_"]);
return s;
}
private static string AttributeEncode(string s)
{
return s.Replace(">", ">").Replace("<", "<").Replace("\"", """);
}
private static readonly char[] _problemUrlChars = @"""'*()[]$:".ToCharArray();
///
/// hex-encodes some unusual "problem" chars in URLs to avoid URL detection problems
///
private string EncodeProblemUrlChars(string url)
{
if (!_encodeProblemUrlCharacters) return url;
var sb = new StringBuilder(url.Length);
bool encode;
char c;
for (int i = 0; i < url.Length; i++)
{
c = url[i];
encode = Array.IndexOf(_problemUrlChars, c) != -1;
if (encode && c == ':' && i < url.Length - 1)
encode = !(url[i + 1] == '/') && !(url[i + 1] >= '0' && url[i + 1] <= '9');
if (encode)
sb.Append("%" + String.Format("{0:x}", (byte)c));
else
sb.Append(c);
}
return sb.ToString();
}
///
/// Within tags -- meaning between < and > -- encode [\ ` * _] so they
/// don't conflict with their use in Markdown for code, italics and strong.
/// We're replacing each such character with its corresponding hash
/// value; this is likely overkill, but it should prevent us from colliding
/// with the escape values by accident.
///
private string EscapeSpecialCharsWithinTagAttributes(string text)
{
var tokens = TokenizeHTML(text);
// now, rebuild text from the tokens
var sb = new StringBuilder(text.Length);
foreach (var token in tokens)
{
string value = token.Value;
if (token.Type == TokenType.Tag)
{
value = value.Replace(@"\", _escapeTable[@"\"]);
if (_autoHyperlink && value.StartsWith("(?=.)", _escapeTable[@"`"]);
value = EscapeBoldItalic(value);
}
sb.Append(value);
}
return sb.ToString();
}
///
/// convert all tabs to _tabWidth spaces;
/// standardizes line endings from DOS (CR LF) or Mac (CR) to UNIX (LF);
/// makes sure text ends with a couple of newlines;
/// removes any blank lines (only spaces) in the text
///
private string Normalize(string text)
{
var output = new StringBuilder(text.Length);
var line = new StringBuilder();
bool valid = false;
for (int i = 0; i < text.Length; i++)
{
switch (text[i])
{
case '\n':
if (valid) output.Append(line);
output.Append('\n');
line.Length = 0; valid = false;
break;
case '\r':
if ((i < text.Length - 1) && (text[i + 1] != '\n'))
{
if (valid) output.Append(line);
output.Append('\n');
line.Length = 0; valid = false;
}
break;
case '\t':
int width = (_tabWidth - line.Length % _tabWidth);
for (int k = 0; k < width; k++)
line.Append(' ');
break;
case '\x1A':
break;
default:
if (!valid && text[i] != ' ') valid = true;
line.Append(text[i]);
break;
}
}
if (valid) output.Append(line);
output.Append('\n');
// add two newlines to the end before return
return output.Append("\n\n").ToString();
}
#endregion
///
/// this is to emulate what's evailable in PHP
///
private static string RepeatString(string text, int count)
{
var sb = new StringBuilder(text.Length * count);
for (int i = 0; i < count; i++)
sb.Append(text);
return sb.ToString();
}
}
}