chickadee » srfi-14 » char-set-difference!

char-set-complement! csprocedure
char-set-union! cs_1 cs_2 ...procedure
char-set-intersection! cs_1 cs_2 ...procedure
char-set-difference! cs_1 cs_2 ...procedure
char-set-xor! cs_1 cs_2 ...procedure
char-set-diff+intersection! cs_1 cs_2 cs_3 ...procedure

These are linear-update variants of the set-algebra functions. They are allowed, but not required, to side-effect their first (required) parameter.

char-set-diff+intersection! is allowed to side-effect both of its two required parameters, CS_1 and CS_2.