emph in parens

[melisgl]

CL-USER> (3bmd-grammar:parse-doc "(_xxx_)")
((:PLAIN "(_xxx" "_" ")"))
NIL
T
CL-USER> (3bmd-grammar:parse-doc "(*xxx*)")
((:PLAIN "(" (:EMPH "xxx") ")"))
NIL
T

The inconsistency is because of

(defrule string (and normal-char (* (or normal-char (and (+ #\_) maybe-alphanumeric))))
  (:text t))

Without going full CommonMark, would it make sense to change this in parser.lisp?

@@ -36,6 +36,7 @@
 (defrule normal-char (and (! (or special-char space-char newline)) character)
   (:text t))
 (defrule special-char (or #\* #\_ #\` #\& #\[ #\] #\< #\! #\# #\\
+                          #\( #\) #\{ #\}
                           extended-special-char)
   (:text t))

which seems to fix this.

[3b]

Looks like commonmark and most others agree that x_xx_x is not emphasis and (_xx_) is, so your fix seems reasonable.