Encyclopedia of Computer Science and Technology

Eiffel 173As with private enterprise, there can also be importantonline privacy issues. Information that has been collecteddigitally is easy to transfer to other agencies or even (as inthe case of DMV information in some states) sold to privatecompanies. Having a clearly spelled-out privacy policy iscrucial.Besides keeping private what people expect to be private,government agencies must also provide informationthat helps ensure public accountability. Information collectedby government agencies is often subject to the Freedomof Information Act (FOIA). This may require that databe provided in a format that is readily accessible.Further ReadingBriefing Book Outline: E-Government. Advisory Committee to theCongressional Internet Caucus. Available online. URL: http://www.netcaucus.org/books/egov2001/. Accessed September18, 2007.Center for Technology in Government. Available online. URL:http://www.ctg.albany.edu. Accessed September 18, 2007.Cordella, Antonio. “E-Government: Towards the E-bureaucraticForm?” Journal of Information Technology 22 (2007): pp. 265–274.Government Computerization (Open Directory). Availableonline. URL: http://www.dmoz.org/Society/Issues/Science_and_Technology/Computers/Government_Computerization/.Accessed September 18, 2007.LaVigne, Mark. “E-Government: Creating Tools of the Trade.”Available online. URL: http://www.netcaucus.org/books/egov2001/pdf/e-govt.pdf. Accessed September 18, 2007.Rosencrance, Linda. “User Satisfaction with Federal GovernmentWeb Sites down Slightly.” Computerworld, September18, 2007. Available online. URL: http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9037079. Accessed September 18, 2007.USA.gov: “Government Made Easy” [Official U.S. GovernmentPortal]. Available online. URL: http://www.usa.gov/. AccessedSeptember 18, 2007.EiffelEiffel is an interesting programming language developedby Bertrand Meyer and his company Eiffel Software in the1980s. The language was named for Gustav Eiffel, the architectwho designed the famous tower in Paris. The languageand accompanying methodology attracted considerableinterest at software engineering conferences.Eiffel fully supports (and in some ways pioneered) programmingconcepts found in more widely used languagestoday (see class and object-oriented programming). Syntactically,Eiffel emphasizes simple, reusable declarations thatmake the program easier to understand, and tries to avoidobscure or lower-level code such as compiler optimizations.Program StructureAn Eiffel program is called a “system,” emphasizing itsstructure as a set of classes that represent the types of realworlddata that need to be processed. A simple class mightlook like this:classCOUNTERfeature—access counter valuetotal: INTEGERfeature—manipulate counter valueincrement is—increase counter by onedototal :- total + 1enddecrement is—decrease counter by onedototal := total - 1endreset is—reset counter to zerodototal := 0endend(In this listing language, keywords are in bold and userdefinedobjects are in italics. This formatting will be doneautomatically as the user enters the text.) Once the class isdefined, making an instance of it is very simple:my_counter COUNTERcreate my_counterThe Eiffel compiler itself compiles to an intermediate“bytecode” that, in the final stage, is compiled into C, takingadvantage of the ready availability of optimized C compilers.A unique feature of Eiffel is the ability to set up “contracts”that specify in detail how classes will interact withone another. (This goes well beyond the usual declarationsof parameters and enforcement of data types.) For example,with the COUNTER class an “invariant” can be declaredsuch that total >= 0. This means that this condition mustalways remain true no matter what. A method can alsorequire that the caller meet certain conditions. After processingand before returning to the caller, the method canensure that a particular condition is true. The point of thesespecifications is that they make explicit what a given unit ofcode expects and what it promises to do in return. This canalso improve program documentation.Implementation and UsesEiffel’s proponents note that it is more than a language: Itis designed to provide consistent ways to revise and reuseprogram components throughout the software developmentcycle. The current implementation of Eiffel is available forvirtually all platforms and has interfaces to C, C++, andother languages. This allows Eiffel to be used to create adesign framework for reusing existing software componentsin other languages. Eiffel’s consistent object-oriented designalso makes it useful for documenting or modeling softwareprojects (see modeling languages).Eiffel was developed around the same time as C++. Eiffelis arguably cleaner and superior in design to the latter language.However, two factors led to the dominance of C++:the ready availability of inexpensive or free compilers andthe existence of thousands of programmers who alreadyknew C. Eiffel ended up being a niche language used for