...
if not BMI.oclIsDefined() then
GLIFDecisionResult{Question = q,Answer = unknown, Reason = "No BMI data entered",Weight = aWeight}
else
if BMI > 25
then
GLIFDecisionResult{Question = q,Answer = true, Reason = "Patient is overweight",Weight = aWeight}
else
GLIFDecisionResult{Question = q,Answer = false, Reason = "Patient is notoverweightnot overweight",Weight = aWeight}
endif
endif
...