(escape s cmap)
Return a new string, using cmap to escape each character ch from s as follows: If (cmap ch) is nil, append ch to the new string. If (cmap ch) is non-nil, append (str (cmap ch)) instead.
;; There should be no space between the \\ and the &, but I don't know how
;; to create that in an example yet.
user=> (clojure.string/escape "I want 1 < 2 as HTML, & other good things."
{\\< "<", \\> ">", \\& "&"})
"I want 1 < 2 as HTML, & other good things."