func convert()

in convert.go [172:295]
93 lines of code
27 McCabe index (conditional complexity)

func convert(val string, retval reflect.Value, options reflect.StructTag) error {
	if ok, err := convertUnmarshal(val, retval); ok {
		return err
	}

	tp := retval.Type()

	// Support for time.Duration
	if tp == reflect.TypeOf((*time.Duration)(nil)).Elem() {
		parsed, err := time.ParseDuration(val)

		if err != nil {
			return err
		}

		retval.SetInt(int64(parsed))
		return nil
	}

	switch tp.Kind() {
	case reflect.String:
		retval.SetString(val)
	case reflect.Bool:
		if val == "" {
			retval.SetBool(true)
		} else {
			b, err := strconv.ParseBool(val)

			if err != nil {
				return err
			}

			retval.SetBool(b)
		}
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		base, err := getBase(options, 10)

		if err != nil {
			return err
		}

		parsed, err := strconv.ParseInt(val, base, tp.Bits())

		if err != nil {
			return err
		}

		retval.SetInt(parsed)
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		base, err := getBase(options, 10)

		if err != nil {
			return err
		}

		parsed, err := strconv.ParseUint(val, base, tp.Bits())

		if err != nil {
			return err
		}

		retval.SetUint(parsed)
	case reflect.Float32, reflect.Float64:
		parsed, err := strconv.ParseFloat(val, tp.Bits())

		if err != nil {
			return err
		}

		retval.SetFloat(parsed)
	case reflect.Slice:
		elemtp := tp.Elem()

		elemvalptr := reflect.New(elemtp)
		elemval := reflect.Indirect(elemvalptr)

		if err := convert(val, elemval, options); err != nil {
			return err
		}

		retval.Set(reflect.Append(retval, elemval))
	case reflect.Map:
		parts := strings.SplitN(val, ":", 2)

		key := parts[0]
		var value string

		if len(parts) == 2 {
			value = parts[1]
		}

		keytp := tp.Key()
		keyval := reflect.New(keytp)

		if err := convert(key, keyval, options); err != nil {
			return err
		}

		valuetp := tp.Elem()
		valueval := reflect.New(valuetp)

		if err := convert(value, valueval, options); err != nil {
			return err
		}

		if retval.IsNil() {
			retval.Set(reflect.MakeMap(tp))
		}

		retval.SetMapIndex(reflect.Indirect(keyval), reflect.Indirect(valueval))
	case reflect.Ptr:
		if retval.IsNil() {
			retval.Set(reflect.New(retval.Type().Elem()))
		}

		return convert(val, reflect.Indirect(retval), options)
	case reflect.Interface:
		if !retval.IsNil() {
			return convert(val, retval.Elem(), options)
		}
	}

	return nil
}