Constants can often be inferred by ROHD automatically, but can also be explicitly defined using Const, which extends Logic.

// a 16 bit constant with value 5
var x = Const(5, width:16);

There is a convenience function for converting binary to an integer:

// this is equvialent to and shorter than int.parse('010101', radix:2)
// you can put underscores to help with readability, they are ignored
bin('01_0101')

Updated: