Multiplicity (2)
The multiplicity count can be fixed or variable. It is usually specified as a range or interval of integer values.
- E.g., [0..1], [1..1], [0..M], [1..M]
- M denotes an unspecified upper bound.
- [0..M] is equivalent to the regular expression exponent *;
- [1..M] is equivalent to the regular expression exponent +.
Complex rules need algorithmic specifications:
- E.g., the set of integers congruent to zero mod 3;
- E.g., the set of strings over alphabet V specified by grammar G .
Complex rules can also be specified by a [meta-]data model which enumerates a set of valid values, intervals and/or data types.