>>1
The markup handlers are defined in lib/markup.scm via transform-rule. You have six examples from "(define bold ..." to "(define link ...". You can define your superscript and subscript handlers based on the examples. You then have to manually add them to both the let and the compose of line-scanner, because the author doesn't keep a simple list of the rules. So instead introduce a list of the rules and rewrite line-scanner to use this list by mapping over it with a lambda that does partial lines->sxml, then pass the map to compose via apply. Because the current line-scanner looks revolting.