(get-char-code-property ?ἀ 'decomposition) returns a list of
two characters into which the given character is decomposed. Is
it possible, given these characters, to recompose the original?
Is there a function for that?
I don't think Emacs has a mapping from the decomposed form back to the original character. You can look it up using
(defun lookup-composed (decomp) (let (composed) (maphash (lambda (key val) (when (equal decomp (get-char-code-property val 'decomposition)) (push val composed))) (ucs-names)) composed))