(defun hangul-character (cho jung jong)
"Convert CHO, JUNG, JONG to the precomposed `Hangul Syllables' character.
-CHO, JUNG, JONG are relative indices in `Hangul Compatibility Jamo' of unicode.
+CHO, JUNG, JONG are relative indices in `Hangul Compatibility Jamo' of Unicode.
Return a zero-length string if the conversion fails."
(or
(decode-char