gistfile1.el

(font-lock-add-keywords
 'php-mode `(("\\(<\\?php echo\\) \\($[^\n>]*\\) \\(\\?>\\)"
             (0 (progn (compose-region (match-beginning 1)
                                       (match-end 1) "{")
                       (compose-region (match-beginning 3)
                                       (match-end 3) "}")
                       nil)))))