Here’s a draft of an extension to do that, in the format I’ve been throwing around:
Extension: Strikethrough
A new inline Markdown element is added, Strikethrough. It follows the same parsing rules as strong emphasis (§6.4), except that the asterisk and underline are replaced by a tilde
~, and the<strong>tag is replaced with the<del>tag.A double
~~can open strikethrough iff
- it is not part of a sequence of 3 or more unescaped
~s, and- it is not followed by whitespace.
A double
~~can close strikethrough iff
- it is not part of a sequence of 3 or more unescaped
~s, and- it is not preceded by whitespace.
Strikethrough has a precedence equal to emphasis and strong emphasis.