added lua interpreter support for custom math functions

go/util.go

@@ -0,0 +1,39 @@
+package main
+
+import "math"
+
+func contains(s []string, e string) bool {
+	for _, a := range s {
+		if a == e {
+			return true
+		}
+	}
+	return false
+}
+
+func const2num(name string) float64 {
+	switch name {
+	case "Pi":
+		return math.Pi
+	case "Phi":
+		return math.Phi
+	case "Sqrt2":
+		return math.Sqrt2
+	case "SqrtE":
+		return math.SqrtE
+	case "SqrtPi":
+		return math.SqrtPi
+	case "SqrtPhi":
+		return math.SqrtPhi
+	case "Ln2":
+		return math.Ln2
+	case "Log2E":
+		return math.Log2E
+	case "Ln10":
+		return math.Ln10
+	case "Log10E":
+		return math.Log10E
+	default:
+		return 0
+	}
+}