Left 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 left.