System and method for compile-time checking of units

Abstract

A system and method create and manipulate variables having both a numeric value and a units designation. The units designation is a vector of unit exponents which are operated upon consistent with operations on values. Exactly defined and underdefined quantities are stored in data structures of values and unit designations. Operations on underdefined quantities may result in expression data structures of operand quantities, operators and unit designations. The system allows the creation of variables having a unit specification and the transparent manipulation of such a variable during conventional numerical and logical operations. The system automatically signals an error condition when an operation is attempted on a set of variables having incompatible units designations. Error conditions can be detected at both compile-time and run-time. The system also includes both a predetermined dictionary of units and a customizable dictionary of units. In addition, conversion factors can be specified allowing the automatic conversion between variable of the same kind (i.e. distance) but different underlying units (i.e. yards and meters.) The invention is implemented on a computer and can be an extension to a programming language resulting in such variables being considered first class data types.