On Tuesday, 9 January 2018, Tom Lane <t...@sss.pgh.pa.us> wrote: > > So the approach I'm imagining now is a datatype-specific support function > along the lines of > > in_range(a, b, delta) returns bool > > which is supposed to return true if a <= b + delta, or something along > that line --- exact details of the definition TBD --- with the proviso > that if b + delta would overflow then the result is automatically true. > > We could probably also delegate the requirement of throwing an error > for negative delta to this function, eliminating the need for the > datatype-independent core code to know how to tell that, which is the > other datatype-dependent behavior needed per spec. > > Likely there are two of these, one each for the PRECEDING and FOLLOWING > cases. > > > Would you prefer two functions, or a single function with a parameter for PRECEDING/FOLLOWING? Maybe:
in_range(a, b, delta, following) returns bool Where following is a bool which is true if FOLLOWING was specified and false if PRECEDING was specified?
