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2 Rules of Methodology
The basic datatypes are written obeying the following rules of
methodology. We formulate them explicitely for several reasons:
- Many design decisions in the basic datatypes make only sense in
context of the rules.
- The rules are useful in general for writing requirement
specifications in CASL.
- The rules can serve as a starting point for a new set of rules
of methodology for other applications.
For the rules we tried to adopt the style of the famous book "A
Pattern Language" [AIS77]. Reflecting the marking of
[AIS77], all of our rules should be marked with one
asterisk. I.e. with the words of [AIS77] we claim that "we
have made some progress", " but with careful work it will certainly
be possible to improve on the solution" - not astonishing, as these
rules are the first "style-guide" how to write specifications in
CASL.
If we had pointed out in the rules themselves that they are rules of thumb,
we would have had to
stress phrasings like "if possible", "if adequate", "whenever
possible" too much. Thus we formulate them as general statements.
Examples from the basic datatypes illustrate their use. The
discussion of a rule justifies the underlying design decision and -
as there is no rule without a meaningful exception - shows its
limitations.
CoFI
Note: M-6 -- Version: 0.2 -- 20 July 1999.
Comments to cofi@informatik.uni-bremen.de