- For commands which need to dynamically determine this behavior.
- FUNCTION should take no argument and return one of the above values or nil."
+ For commands which need to dynamically determine this
+ behavior. FUNCTION should take no argument and return a
+ value acceptable as TYPE, or nil. In the latter case,
+ FUNCTION should itself do with the active region whatever is
+ appropriate.
+ Other non-nil values
+ The normal case: delete the active region prior to executing
+ the command which will insert replacement text."