In normal RegEx
\l will make the character to the right lowercase. However, it seems like the RegEx in Mathematica does not have this functionality.
will return the following error message
RegularExpression::msg37: "Mathematica does not support \\L, \\l, \\N, \\P, \\p, \\U, \\u, or \\X in RegularExpression[\!\(\"(.).*?\\\\l\\\\1\"\)]."
Is there some workaround that I can use? Note that
(?i) is not sufficient as I need the character to be lowercase only.