Language design is a most difficult task. While the original design of a language has the distinct advantage of filling a blank page, the revision of a language needs to abide by a number of constraints that limit the...
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Language design is a most difficult task. While the original design of a language has the distinct advantage of filling a blank page, the revision of a language needs to abide by a number of constraints that limit the degree of design freedom. Ada was developed with a number of underlying design principles and concepts. Revisions to the language must be in consonance with this existing overall philosophy of Ada. Extensions need to fit into this philosophy. This not only makes the description of Ada 9X easier, but facilitates the training of personnel in the revised language. Ada engineers should not need to change their style of design and programming in order to use Ada 9X, and must be able to gradually migrate to Ada 9X as they explore and experiment with the newly provided capabilities. A most stringent constraint on the language revision is the desire to keep the revised language upward compatible with the existing standard. One needs to take into account millions of lines of existing Ada code in development, use and maintenance today which eventually will be migrated to Ada 9X environments.
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