Modularity and Extendibility the Speciication Is Split in 22 Montages. Each Acknowledgments We Would like to Thank to Tonio, and Christoph Denzler for Their Help with Gem-mex and Their Collaboration in the Montages Project, and To

A complete, exible compiler construction system. Simplicity Only simple imperative updates and drawings of control and data ow graphs are used to specify the language. Only 28 diierent symbols (for variables, macros, e.t.c.) are used in addition to the symbols introduced by the EBNF syntax-rules. The whole textual speciication of static and dynamic semantics is 92 lines long. Montage speciies one language construct. Most information is local, and changes of one Montage do not aaect the other Montages. Self documenting The simplicity, shortness, and modularity of the speciication make it usable as documentation as well. Using again the Montages of CML, Gem-Mex generates HTML and paper versions of the language description. The Montages approach could be learned within one day by an industrial programmer, and allows the CUBIX developer to extend the language if new problems appear. item EEciency From the Montages speciications of CML, Gem-Mex generates an interpreter. This interpreter is eecient enough to be used in the operational version of CUBIX. Calculating the SQL queries for a report with 100 result values, using a complicate driver speciication takes about 1.5 seconds on an Ultra30, for a simple speciication about 0.6 seconds. Portability Gem-Mex generates C-code, that can be compiled on arbitrary ar-chitectures and operating systems. Gem-Mex itself is only based on C and TclTk, which exist on all commercial platforms, like Windows, Windows NT, Unix. The tools can thus easily be integrated in a developer version of CUBIX. It has been shown that abstract state machines Gur95] structed with Montages KP97] are well suited to deene domain speciic languages. The formal speciication of the language CML has been a starting point to successfully introduce formal methods into an industrial setting. In particular, formal methods specialists can read Montage models since the semantics of abstract state machines is a mathematical object. Domain experts need not learn other formal methods in order to validate the developed formalizations. Therefore, formal methods far above the complexity understandable by domain experts can be applied, if a Montage/ASM speciication exists. 13 in time even in a non-monotonic way since modiications can be localized within very neat boundaries. By doing so, diierent experimentation can take place with diierent versions of the syntax and semantics of the speciied language in a very short time. Besides the pure editing functionality, Gem can be used to generate documents suitable for speciication presentation. Experience suggests how lack in documentation …