60. The computer as claimed in claim 59, wherein said separate portion of said knowledge base encoding said control knowledge comprises a plurality of discrete control blocks, each control block including statements in said imperative procedural language, said procedural language including separate statements to ask the user a question and obtain a responsive answer, apply a specified set of said judgmental rules, display to the user the conclusions of the rules applied, and to execute another specified control block.
60. The computer as claimed in claim 59, wherein said separate portion of said knowledge base encoding said control knowledge comprises a plurality of discrete control blocks, each control block including statements in said imperative procedural language, said procedural language including separate statements to ask the user a question and obtain a responsive answer, apply a specified set of said judgmental rules, display to the user the conclusions of the rules applied, and to execute another specified control block. 63. The computer as claimed in claim 60, wherein said factual knowledge includes means for defining at least one attribute capable of having a respective value, one of the judgmental rules concludes a value for said attribute when it is applied by said inference engine, said plurality of discrete control blocks includes a post-determination control block using the concluded value for said attribute, and said language interpreter means includes means for interrupting the execution of said procedural language to execute the procedural language statements in the post-determination control block when said judgmental rule determines a value for said attribute.