compose-string-internalcompose-string-internal is a built-in function in `
C source code'. (compose-string-internal STRING START END &optional COMPONENTS MODIFICATION-FUNC) Internal use only. Compose text between indices START and END of STRING, where START and END are treated as in `substring'. Optional 4th and 5th arguments are COMPONENTS and MODIFICATION-FUNC for the composition. See `compose-string' for more details.