Here's the code that should do what you want:
(defvar pretty-alist
(cl-pairlis '("alpha" "beta" "gamma" "delta" "epsilon" "zeta" "eta"
"theta" "iota" "kappa" "lambda" "mu" "nu" "xi"
"omicron" "pi" "rho" "sigma_final" "sigma" "tau"
"upsilon" "phi" "chi" "psi" "omega")
(mapcar
(lambda (x) (make-char 'greek-iso8859-7 x))
(number-sequence 97 121))))
(add-to-list 'pretty-alist '("rangle" . ?\⟩))
(defun pretty-things ()
(mapc
(lambda (x)
(let ((word (car x))
(char (cdr x)))
(font-lock-add-keywords
nil
`((,(concat "\\(^\\|[^a-zA-Z0-9]\\)\\(" word "\\)[a-zA-Z]")
(0 (progn
(decompose-region (match-beginning 2) (match-end 2))
nil)))))
(font-lock-add-keywords
nil
`((,(concat "\\(^\\|[^a-zA-Z0-9]\\)\\(" word "\\)[^a-zA-Z]")
(0 (progn
(compose-region (1- (match-beginning 2)) (match-end 2)
,char)
nil)))))))
pretty-alist))
As you can see above, pretty-alist
starts out with greek chars. Then I add
\rangle
just to demonstrate how to add new things.
To enable it automatically, add it to the hook:
(add-hook 'LaTeX-mode-hook 'pretty-things)
I used the code from here as a starting point, you can look there for a reference.