A number of options exist for displaying SNOMED CT Expression Constraints, including:
- Displaying the expression constraint using SNOMED CT Expression Constraint Language
in its originally authored and stored form;
- Converting the expression constraint to use either all symbols (as per the Brief Syntax),
or all human-readable operators (as per alternate text introduced in the Long Syntax);
- Enhancing the expression constraint by adding in terms that may have been omitted,
or replacing the existing terms with either local-dialect Preferred Terms or Fully
Specified Names;
- Hiding the SNOMED CT identifiers for each concept and displaying only the Preferred
Terms;
- Enhancing the display by using different font colors for each different part of the
expression constraint (e.g. identifiers, terms, vertical bars, and operators), and
by using whitespace in a way that improves the readability of the expression;
- Automatically transforming the expression constraint into a human-readable string
using a predefined algorithm. For example, a simple algorithm may convert the symbols
to text and remove the concept identifiers – e.g. "Descendants of fracture of bone:
Finding site = Descendants or self of arm". More sophisticated algorithms may use
pattern matching and predefined templates to construct a more natural string;
- Representing the operators, operands and attribute values of the expression constraint
by populating a structured form. This approach is primarily suited to expression constraints
with a consistent template, where the form can be pre-designed.
Which of these options is most appropriate to use when displaying expression constraints,
will depend on a number of factors, including the type of users that will be viewing
the constraints, the scope of the required constraint functionality, and the capabilities
of the system implementation.