Djang et al. [1998] introduced a new model of types for declarative visual programming languages (VPLs). Implicit static typing is used in their type model, in order to eliminate the programming mechanisms associated with type declarations, provide immediate visual feedback with respect to type errors and guarantee type safe programs. Their type model also evaluates types on a level of granularity that is finer than in previous approaches to types. Instead of evaluating types on the basis of abstract names, their model determines a set of operations that an object guarantees and compares this set to the set of operations this object is required to support. If the set of required operations is a subset of the set of guaranteed operations, then the object is considered type safe. This granularity provides their model with the ability to support inheritance without introducing explicit type declarations and to communicate type errors to users without requiring the user to understand a large set of terminology. These features of their model attempt to provide VPL users with more powerful programming capabilities without the introduction of a high learning curve.
In this thesis, an implementation of the Djang et al.'s model of types is presented. Data structures and algorithms are developed that conform to the axioms prescribed by Djang et al. The space and time complexity analyses for our data structures and algorithms are examined. Our implementation provides new insights into the cost and performance of the Djang et al.'s type model. / Graduation date: 2000
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33386 |
| Date | 09 September 1999 |
| Creators | Chen, Roger Ding-Fu |
| Contributors | Burnett, Margaret M. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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