Bold italic creates improperly nested tags

[chas]

When converting ***bold italic text*** to bold italic, the result is

<strong><em>bold italic text</strong></em>

because the Regex grabs the first ** of the final *** instead of closing the * first. The easiest solution is to parse *** as nested tags.

Thus this:

	# Pattern to match strong emphasis in Markdown text
	BoldRegexp = %r{ (\*\*|__) (\S|\S.+?\S) \1 }x

	# Pattern to match normal emphasis in Markdown text
	ItalicRegexp = %r{ (\*|_) (\S|\S.+?\S) \1 }x

	### Transform italic- and bold-encoded text in a copy of the specified +str+
	### and return it.
	def transform_italic_and_bold( str, rs )
		@log.debug " Transforming italic and bold"

		str.
			gsub( BoldRegexp, %{<strong>\\2</strong>} ).
			gsub( ItalicRegexp, %{<em>\\2</em>} )
	end

Becomes this:

	# Pattern to match strong emphasis and emphasis in Markdown text
	BoldItalicRegexp = %r{ (\*\*\*|___) (\S|\S.+?\S) \1 }x

	# Pattern to match strong emphasis in Markdown text
	BoldRegexp = %r{ (\*\*|__) (\S|\S.+?\S) \1 }x

	# Pattern to match normal emphasis in Markdown text
	ItalicRegexp = %r{ (\*|_) (\S|\S.+?\S) \1 }x

	### Transform italic- and bold-encoded text in a copy of the specified +str+
	### and return it.
	def transform_italic_and_bold( str, rs )
		@log.debug " Transforming italic and bold"

		str.
			gsub( BoldItalicRegexp, %{<strong><em>\\2</em></strong>} ).
			gsub( BoldRegexp, %{<strong>\\2</strong>} ).
			gsub( ItalicRegexp, %{<em>\\2</em>} )
	end

A workaround is to mix _ and * syntax: _**bold italic text**_ or **_bold italic text_**.