set-case-syntax-pair

set-case-syntax-pair is a compiled Lisp function in `case-table.el'.

(set-case-syntax-pair UC LC TABLE)

Make characters UC and LC a pair of inter-case-converting letters.
This sets the entries for characters UC and LC in TABLE, which is a string
that will be used as the downcase part of a case table.
It also modifies `standard-syntax-table' to give them the syntax of
word constituents.