Variable: compose-chars-after-function

Function to adjust composition of buffer text.

This function is called with three arguments: FROM, TO, and OBJECT.
FROM and TO specify the range of text whose composition should be
adjusted. OBJECT, if non-nil, is a string that contains the text.

This function is called after a text with `composition' property is
inserted or deleted to keep `composition' property of buffer text

The default value is the function `compose-chars-after'.