added Convert

.gitignore

@@ -13,3 +13,4 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+__debug_bin

measureable_units.go

@@ -193,3 +193,34 @@ func (x ViscosityUnit) DisplayName() string {
 	tt := proto.GetExtension(test, E_DisplayName)
 	return tt.(string)
 }
+
+func (x *VolumeType) Convert(unit VolumeUnit) *VolumeType {
+	test := x.Unit.Descriptor().Values().ByNumber(x.Unit.Number()).Options()
+	tt := proto.GetExtension(test, E_ConversionVolumeUnit)
+	response := &VolumeType{
+		Unit:  unit,
+		Value: x.Value,
+	}
+	c, ok := tt.(*ConversionVolumeUnit)
+	if ok {
+		for _, r := range c.Rates {
+			if r.Target == unit {
+				switch r.Operator {
+				case ArithmeticOperators_ARITHMETIC_OPERATORS_ADDITION:
+					response.Value = x.Value + r.Value
+				case ArithmeticOperators_ARITHMETIC_OPERATORS_SUBTRACTION:
+					response.Value = x.Value - r.Value
+				case ArithmeticOperators_ARITHMETIC_OPERATORS_MULTIPLICATION:
+					response.Value = x.Value * r.Value
+				case ArithmeticOperators_ARITHMETIC_OPERATORS_DIVISION:
+					response.Value = x.Value / r.Value
+				case ArithmeticOperators_ARITHMETIC_OPERATORS_UNSPECIFIED:
+					response.Value = x.Value
+				}
+				break
+			}
+		}
+	}
+
+	return response
+}

measureable_units_test.go

@@ -0,0 +1,22 @@
+package beerprotov1
+
+import (
+	"fmt"
+	"testing"
+)
+
+func Test_main(t *testing.T) {
+
+	vol := &VolumeType{
+		Unit:  VolumeUnit_VOLUME_UNIT_ML,
+		Value: 5,
+	}
+
+	got := vol.Convert(VolumeUnit_VOLUME_UNIT_L)
+
+	if got.Value != 0.005 {
+		t.Errorf("Convert(5) = %v; want 0.005", got.Value)
+	}
+	fmt.Print(vol)
+
+}