This case-sensitive code system http://hl7.org/fhir/assert-operator-codes defines the following codes:
Code
Display
Definition
equals
equals
Default value. Equals comparison.
notEquals
notEquals
Not equals comparison.
in
in
Compare value within a known set of values.
notIn
notIn
Compare value not within a known set of values.
greaterThan
greaterThan
Compare value to be greater than a known value.
lessThan
lessThan
Compare value to be less than a known value.
empty
empty
Compare value is empty.
notEmpty
notEmpty
Compare value is not empty.
contains
contains
Compare value string contains a known value.
notContains
notContains
Compare value string does not contain a known value.
eval
evaluate
Evaluate the FHIRPath expression as a boolean condition.
manualEval
manualEvaluate
Manually evaluate the condition described by this assert. The test engine SHALL pause and provide an input mechanism to set the outcome of this assert to 'pass', 'fail', 'skip' or 'stop'.