ELAN - Related Systems

ELAN has similarities with other rule-based systems like ASF+SDF, CafeObj, and Maude. Compared to them, ELAN has some positive aspects: On the other hand, ELAN has also a few weaknesses with respect to these other systems. First of all, the use of an exchange format for ELAN is quite new, and the REF format should only be considered as a first attempt. On this point, there is much more expertise in ASF+SDF with the AsFix format and the toolBus architecture ASF2 for the interconnection of AsFix-based tools. Since the ASF+SDF system has been designed as a meta-environment for prototyping programming languages, a formalism for the syntax definition has been carefully worked out. The ELAN system is comparable to the ASF part, but does not incorporate the facilities to specify user-defined lexical entities.

An exchange format is also a possible solution to deal with reflection facilities which are already fully integrated into Maude . Moreover, Maude allows several possible equational axioms on user-defined function symbols like associativity, commutativity, identity, idempotency,... and their combinations, whilst ELAN only handles associativity-commutativity (possibly a combination of different AC-symbols).

Behavioural specifications with hidden sorts and states, order-sorted sorts, and object orientation, provided in CafeObj, have not been integrated in ELAN. All these points provide potential further improvements of ELAN. 

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