AfterPrint -- top level method applied after printing

Synopsis

Usage:

X#{topLevelMode,AfterPrint} = f
Inputs:
- f, a function to be applied after printing a top-level evaluation result r of type X.
Outputs:
- The value returned by f is discarded.

This method is used to print the type of the result of a computation.

i1 : 3/4

     3
o1 = -
     4

o1 : QQ

We could suppress that output for a single type as follows.

i2 : QQ#{topLevelMode,AfterPrint} = r -> r;

The object AfterPrint is a symbol.