The biggest change introduced by IDL 8.4 is the treatment of all variables as objects. Every variable now has attributes that you would normally get returned from the SIZE function: length, ndim, dim, tname, typecode, and typename. For example:

IDL> a = bindgen(2, 3)
IDL> print, a.length
IDL> print, a.ndim
IDL> print, a.dim
           2           3
IDL> print, a.tname

There are also static methods available for all variables:

IDL> n = 50
IDL> print, n->toString()

Strings, numbers, integers, and pointers have their own set of special methods appropriate for their respective types. For example integers have some handle base conversion methods:

IDL> print, n->toHex()
IDL> print, n->toBinary()

Strings have some methods that are not available through other IDL library routines, including the very useful replace method:

IDL> s = 'ITT VIS'
IDL> print, s.replace('ITT', 'Exelis')
Exelis VIS