... Calibration of and imaging from data measured by synthesis arrays is accomplished in AIPS++ using a very general formulation of interferometry due to Hamaker, Bregman, & Sault (1996). ... We describe the design, the design process, and some details of the implementation. ... This difficulty is of course one of the motivations for the AIPS++ Project, in which object-oriented techniques have been adopted with the goal of simplifying development and maintenance of processing algorithms. ... calibrater ...