Created structure for opinion + NewOpinion

opinion.go

@@ -0,0 +1,40 @@
+package sublogic
+
+import (
+	"errors"
+)
+
+type Opinion struct {
+	Belief      float32
+	Disbelief   float32
+	Uncertainty float32
+	Baserate    float32
+}
+
+// Creates a new opinion.
+// 
+// Opinion must satisfy the following:
+// - belief + disbelief + uncertainty = 1
+// - Each component must be in the range of 0 to 1
+func NewOpinion(belief, disbelief, uncertainty, baserate float32) (*Opinion, error) {
+	// Test for valid opinion
+	if val := belief + disbelief + uncertainty; val != 1 {
+		return nil, errors.New("The sum of all opinion components doesn't equal 1")
+	}
+
+	outOfRange := func(val float32) bool {
+		if (val < 0) || (val > 1) {
+			return true
+		}
+		return false
+	}
+
+	if outOfRange(belief) || outOfRange(disbelief) || outOfRange(uncertainty) || outOfRange(baserate) {
+		return nil, errors.New("Opinion component isn't in range of 0 to 1")
+	}
+
+
+	opinion := Opinion{ belief, disbelief, uncertainty, baserate }
+	return &opinion, nil
+}
+