@example
@group
-(char-to-string (char-after 1))
+(string (char-after 1))
@result{} "@@"
@end group
@end example
@end group
@group
-(char-to-string (preceding-char))
+(string (preceding-char))
@result{} "a"
-(char-to-string (following-char))
+(string (following-char))
@result{} "c"
@end group
@end example