Right shift.
Every expression with the >> operator becomes a call to
this function, i.e. a>>b is the same as
predef::`>>(a,b).
If arg1 is an object that implements lfun::`>>() , that
function will be called with arg2 as the single argument.
If arg2 is an object that implements lfun::``>>() , that
function will be called with arg1 as the single argument.
Otherwise arg1 will be shifted arg2 bits right.
`>=()