Some thoughts on CommonMark Syntax


#1

According to CommonMark specification:

 

Type Main Syntax Alternative Syntax HTML
Italic *Italic* _Italic_ Italic
Bold **Bold** __Bold__ Bold

 

While the main syntax seems to me reasonably intuitive, the alternative syntax is not.
IMHO, underscore is more related to underline and/or subscript than to italics.

 

Moreover, underline, subscripts and superscripts are not in the specification, although they are used with certain frequency (probably as much or more than strikethrough).
Therefore, a new specification might be the following:

 

Type Main Syntax Alternative Syntax HTML
Italic *Italic* Italic
Bold **Bold** Bold
Underline __Underline__ Underline
Subscript CO_2 H_2_O , one_two three_ CO2, H2O, onetwo three
Superscript 19^th century sample^multiple words^ 19th century, samplemultiple words

 

What are your thoughts on that?


#2

The underline syntax proposed here would clash with the existing Markdown syntax for strong emphasis. Since the goal of CommonMark is to be highly compatible, changing the syntax in such a fundamental way isn’t really an option. Related discussion about adding underline support to CommonMark.

For sub/superscript, there’s a good discussion with syntax proposals in this topic.