1. A method of linking simulators to a circuit design tool, comprising: on a processor, performing operations including: establishing a plurality of simulator objects in memory accessible to the circuit design tool in response to a plurality of registration commands input to the circuit design tool, respectively, each registration command specifying a respective simulation interface application associated with one of the simulators, and the respective simulation interface application having procedures for initiating functions of the associated simulator; for each simulator, storing values of properties of the simulator in the respective simulator object, the values of the properties including references to the procedures of the associated simulation interface application; wherein each simulator object and associated simulation interface application links the circuit design tool to one of the simulators without compilation of the circuit design tool; accessing, responsive to input commands to an interface, the values of the properties and executing the procedures referenced by the values of the properties to initiate the functions of the simulators; and initiating by the interface, a compilation procedure of the simulation interface application in response to user input that specifies a compilation property of the simulator object, and executing by the compilation procedure a compilation function of the simulator that compiles a circuit design.