--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/github.com/spf13/cast/caste.go	Sat Sep 29 18:09:54 2018 +0200
@@ -0,0 +1,1166 @@
+// Copyright © 2014 Steve Francia <spf@spf13.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+package cast
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"html/template"
+	"reflect"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var errNegativeNotAllowed = errors.New("unable to cast negative value")
+
+// ToTimeE casts an interface to a time.Time type.
+func ToTimeE(i interface{}) (tim time.Time, err error) {
+	i = indirect(i)
+
+	switch v := i.(type) {
+	case time.Time:
+		return v, nil
+	case string:
+		return StringToDate(v)
+	case int:
+		return time.Unix(int64(v), 0), nil
+	case int64:
+		return time.Unix(v, 0), nil
+	case int32:
+		return time.Unix(int64(v), 0), nil
+	case uint:
+		return time.Unix(int64(v), 0), nil
+	case uint64:
+		return time.Unix(int64(v), 0), nil
+	case uint32:
+		return time.Unix(int64(v), 0), nil
+	default:
+		return time.Time{}, fmt.Errorf("unable to cast %#v of type %T to Time", i, i)
+	}
+}
+
+// ToDurationE casts an interface to a time.Duration type.
+func ToDurationE(i interface{}) (d time.Duration, err error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case time.Duration:
+		return s, nil
+	case int, int64, int32, int16, int8, uint, uint64, uint32, uint16, uint8:
+		d = time.Duration(ToInt64(s))
+		return
+	case float32, float64:
+		d = time.Duration(ToFloat64(s))
+		return
+	case string:
+		if strings.ContainsAny(s, "nsuµmh") {
+			d, err = time.ParseDuration(s)
+		} else {
+			d, err = time.ParseDuration(s + "ns")
+		}
+		return
+	default:
+		err = fmt.Errorf("unable to cast %#v of type %T to Duration", i, i)
+		return
+	}
+}
+
+// ToBoolE casts an interface to a bool type.
+func ToBoolE(i interface{}) (bool, error) {
+	i = indirect(i)
+
+	switch b := i.(type) {
+	case bool:
+		return b, nil
+	case nil:
+		return false, nil
+	case int:
+		if i.(int) != 0 {
+			return true, nil
+		}
+		return false, nil
+	case string:
+		return strconv.ParseBool(i.(string))
+	default:
+		return false, fmt.Errorf("unable to cast %#v of type %T to bool", i, i)
+	}
+}
+
+// ToFloat64E casts an interface to a float64 type.
+func ToFloat64E(i interface{}) (float64, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case float64:
+		return s, nil
+	case float32:
+		return float64(s), nil
+	case int:
+		return float64(s), nil
+	case int64:
+		return float64(s), nil
+	case int32:
+		return float64(s), nil
+	case int16:
+		return float64(s), nil
+	case int8:
+		return float64(s), nil
+	case uint:
+		return float64(s), nil
+	case uint64:
+		return float64(s), nil
+	case uint32:
+		return float64(s), nil
+	case uint16:
+		return float64(s), nil
+	case uint8:
+		return float64(s), nil
+	case string:
+		v, err := strconv.ParseFloat(s, 64)
+		if err == nil {
+			return v, nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v of type %T to float64", i, i)
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to float64", i, i)
+	}
+}
+
+// ToFloat32E casts an interface to a float32 type.
+func ToFloat32E(i interface{}) (float32, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case float64:
+		return float32(s), nil
+	case float32:
+		return s, nil
+	case int:
+		return float32(s), nil
+	case int64:
+		return float32(s), nil
+	case int32:
+		return float32(s), nil
+	case int16:
+		return float32(s), nil
+	case int8:
+		return float32(s), nil
+	case uint:
+		return float32(s), nil
+	case uint64:
+		return float32(s), nil
+	case uint32:
+		return float32(s), nil
+	case uint16:
+		return float32(s), nil
+	case uint8:
+		return float32(s), nil
+	case string:
+		v, err := strconv.ParseFloat(s, 32)
+		if err == nil {
+			return float32(v), nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v of type %T to float32", i, i)
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to float32", i, i)
+	}
+}
+
+// ToInt64E casts an interface to an int64 type.
+func ToInt64E(i interface{}) (int64, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case int:
+		return int64(s), nil
+	case int64:
+		return s, nil
+	case int32:
+		return int64(s), nil
+	case int16:
+		return int64(s), nil
+	case int8:
+		return int64(s), nil
+	case uint:
+		return int64(s), nil
+	case uint64:
+		return int64(s), nil
+	case uint32:
+		return int64(s), nil
+	case uint16:
+		return int64(s), nil
+	case uint8:
+		return int64(s), nil
+	case float64:
+		return int64(s), nil
+	case float32:
+		return int64(s), nil
+	case string:
+		v, err := strconv.ParseInt(s, 0, 0)
+		if err == nil {
+			return v, nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v of type %T to int64", i, i)
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	case nil:
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to int64", i, i)
+	}
+}
+
+// ToInt32E casts an interface to an int32 type.
+func ToInt32E(i interface{}) (int32, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case int:
+		return int32(s), nil
+	case int64:
+		return int32(s), nil
+	case int32:
+		return s, nil
+	case int16:
+		return int32(s), nil
+	case int8:
+		return int32(s), nil
+	case uint:
+		return int32(s), nil
+	case uint64:
+		return int32(s), nil
+	case uint32:
+		return int32(s), nil
+	case uint16:
+		return int32(s), nil
+	case uint8:
+		return int32(s), nil
+	case float64:
+		return int32(s), nil
+	case float32:
+		return int32(s), nil
+	case string:
+		v, err := strconv.ParseInt(s, 0, 0)
+		if err == nil {
+			return int32(v), nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v of type %T to int32", i, i)
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	case nil:
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to int32", i, i)
+	}
+}
+
+// ToInt16E casts an interface to an int16 type.
+func ToInt16E(i interface{}) (int16, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case int:
+		return int16(s), nil
+	case int64:
+		return int16(s), nil
+	case int32:
+		return int16(s), nil
+	case int16:
+		return s, nil
+	case int8:
+		return int16(s), nil
+	case uint:
+		return int16(s), nil
+	case uint64:
+		return int16(s), nil
+	case uint32:
+		return int16(s), nil
+	case uint16:
+		return int16(s), nil
+	case uint8:
+		return int16(s), nil
+	case float64:
+		return int16(s), nil
+	case float32:
+		return int16(s), nil
+	case string:
+		v, err := strconv.ParseInt(s, 0, 0)
+		if err == nil {
+			return int16(v), nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v of type %T to int16", i, i)
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	case nil:
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to int16", i, i)
+	}
+}
+
+// ToInt8E casts an interface to an int8 type.
+func ToInt8E(i interface{}) (int8, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case int:
+		return int8(s), nil
+	case int64:
+		return int8(s), nil
+	case int32:
+		return int8(s), nil
+	case int16:
+		return int8(s), nil
+	case int8:
+		return s, nil
+	case uint:
+		return int8(s), nil
+	case uint64:
+		return int8(s), nil
+	case uint32:
+		return int8(s), nil
+	case uint16:
+		return int8(s), nil
+	case uint8:
+		return int8(s), nil
+	case float64:
+		return int8(s), nil
+	case float32:
+		return int8(s), nil
+	case string:
+		v, err := strconv.ParseInt(s, 0, 0)
+		if err == nil {
+			return int8(v), nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v of type %T to int8", i, i)
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	case nil:
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to int8", i, i)
+	}
+}
+
+// ToIntE casts an interface to an int type.
+func ToIntE(i interface{}) (int, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case int:
+		return s, nil
+	case int64:
+		return int(s), nil
+	case int32:
+		return int(s), nil
+	case int16:
+		return int(s), nil
+	case int8:
+		return int(s), nil
+	case uint:
+		return int(s), nil
+	case uint64:
+		return int(s), nil
+	case uint32:
+		return int(s), nil
+	case uint16:
+		return int(s), nil
+	case uint8:
+		return int(s), nil
+	case float64:
+		return int(s), nil
+	case float32:
+		return int(s), nil
+	case string:
+		v, err := strconv.ParseInt(s, 0, 0)
+		if err == nil {
+			return int(v), nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v of type %T to int", i, i)
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	case nil:
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to int", i, i)
+	}
+}
+
+// ToUintE casts an interface to a uint type.
+func ToUintE(i interface{}) (uint, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case string:
+		v, err := strconv.ParseUint(s, 0, 0)
+		if err == nil {
+			return uint(v), nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v to uint: %s", i, err)
+	case int:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint(s), nil
+	case int64:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint(s), nil
+	case int32:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint(s), nil
+	case int16:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint(s), nil
+	case int8:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint(s), nil
+	case uint:
+		return s, nil
+	case uint64:
+		return uint(s), nil
+	case uint32:
+		return uint(s), nil
+	case uint16:
+		return uint(s), nil
+	case uint8:
+		return uint(s), nil
+	case float64:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint(s), nil
+	case float32:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint(s), nil
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	case nil:
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to uint", i, i)
+	}
+}
+
+// ToUint64E casts an interface to a uint64 type.
+func ToUint64E(i interface{}) (uint64, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case string:
+		v, err := strconv.ParseUint(s, 0, 64)
+		if err == nil {
+			return v, nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v to uint64: %s", i, err)
+	case int:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint64(s), nil
+	case int64:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint64(s), nil
+	case int32:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint64(s), nil
+	case int16:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint64(s), nil
+	case int8:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint64(s), nil
+	case uint:
+		return uint64(s), nil
+	case uint64:
+		return s, nil
+	case uint32:
+		return uint64(s), nil
+	case uint16:
+		return uint64(s), nil
+	case uint8:
+		return uint64(s), nil
+	case float32:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint64(s), nil
+	case float64:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint64(s), nil
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	case nil:
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to uint64", i, i)
+	}
+}
+
+// ToUint32E casts an interface to a uint32 type.
+func ToUint32E(i interface{}) (uint32, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case string:
+		v, err := strconv.ParseUint(s, 0, 32)
+		if err == nil {
+			return uint32(v), nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v to uint32: %s", i, err)
+	case int:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint32(s), nil
+	case int64:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint32(s), nil
+	case int32:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint32(s), nil
+	case int16:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint32(s), nil
+	case int8:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint32(s), nil
+	case uint:
+		return uint32(s), nil
+	case uint64:
+		return uint32(s), nil
+	case uint32:
+		return s, nil
+	case uint16:
+		return uint32(s), nil
+	case uint8:
+		return uint32(s), nil
+	case float64:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint32(s), nil
+	case float32:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint32(s), nil
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	case nil:
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to uint32", i, i)
+	}
+}
+
+// ToUint16E casts an interface to a uint16 type.
+func ToUint16E(i interface{}) (uint16, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case string:
+		v, err := strconv.ParseUint(s, 0, 16)
+		if err == nil {
+			return uint16(v), nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v to uint16: %s", i, err)
+	case int:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint16(s), nil
+	case int64:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint16(s), nil
+	case int32:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint16(s), nil
+	case int16:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint16(s), nil
+	case int8:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint16(s), nil
+	case uint:
+		return uint16(s), nil
+	case uint64:
+		return uint16(s), nil
+	case uint32:
+		return uint16(s), nil
+	case uint16:
+		return s, nil
+	case uint8:
+		return uint16(s), nil
+	case float64:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint16(s), nil
+	case float32:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint16(s), nil
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	case nil:
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to uint16", i, i)
+	}
+}
+
+// ToUint8E casts an interface to a uint type.
+func ToUint8E(i interface{}) (uint8, error) {
+	i = indirect(i)
+
+	switch s := i.(type) {
+	case string:
+		v, err := strconv.ParseUint(s, 0, 8)
+		if err == nil {
+			return uint8(v), nil
+		}
+		return 0, fmt.Errorf("unable to cast %#v to uint8: %s", i, err)
+	case int:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint8(s), nil
+	case int64:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint8(s), nil
+	case int32:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint8(s), nil
+	case int16:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint8(s), nil
+	case int8:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint8(s), nil
+	case uint:
+		return uint8(s), nil
+	case uint64:
+		return uint8(s), nil
+	case uint32:
+		return uint8(s), nil
+	case uint16:
+		return uint8(s), nil
+	case uint8:
+		return s, nil
+	case float64:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint8(s), nil
+	case float32:
+		if s < 0 {
+			return 0, errNegativeNotAllowed
+		}
+		return uint8(s), nil
+	case bool:
+		if s {
+			return 1, nil
+		}
+		return 0, nil
+	case nil:
+		return 0, nil
+	default:
+		return 0, fmt.Errorf("unable to cast %#v of type %T to uint8", i, i)
+	}
+}
+
+// From html/template/content.go
+// Copyright 2011 The Go Authors. All rights reserved.
+// indirect returns the value, after dereferencing as many times
+// as necessary to reach the base type (or nil).
+func indirect(a interface{}) interface{} {
+	if a == nil {
+		return nil
+	}
+	if t := reflect.TypeOf(a); t.Kind() != reflect.Ptr {
+		// Avoid creating a reflect.Value if it's not a pointer.
+		return a
+	}
+	v := reflect.ValueOf(a)
+	for v.Kind() == reflect.Ptr && !v.IsNil() {
+		v = v.Elem()
+	}
+	return v.Interface()
+}
+
+// From html/template/content.go
+// Copyright 2011 The Go Authors. All rights reserved.
+// indirectToStringerOrError returns the value, after dereferencing as many times
+// as necessary to reach the base type (or nil) or an implementation of fmt.Stringer
+// or error,
+func indirectToStringerOrError(a interface{}) interface{} {
+	if a == nil {
+		return nil
+	}
+
+	var errorType = reflect.TypeOf((*error)(nil)).Elem()
+	var fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
+
+	v := reflect.ValueOf(a)
+	for !v.Type().Implements(fmtStringerType) && !v.Type().Implements(errorType) && v.Kind() == reflect.Ptr && !v.IsNil() {
+		v = v.Elem()
+	}
+	return v.Interface()
+}
+
+// ToStringE casts an interface to a string type.
+func ToStringE(i interface{}) (string, error) {
+	i = indirectToStringerOrError(i)
+
+	switch s := i.(type) {
+	case string:
+		return s, nil
+	case bool:
+		return strconv.FormatBool(s), nil
+	case float64:
+		return strconv.FormatFloat(s, 'f', -1, 64), nil
+	case float32:
+		return strconv.FormatFloat(float64(s), 'f', -1, 32), nil
+	case int:
+		return strconv.Itoa(s), nil
+	case int64:
+		return strconv.FormatInt(s, 10), nil
+	case int32:
+		return strconv.Itoa(int(s)), nil
+	case int16:
+		return strconv.FormatInt(int64(s), 10), nil
+	case int8:
+		return strconv.FormatInt(int64(s), 10), nil
+	case uint:
+		return strconv.FormatInt(int64(s), 10), nil
+	case uint64:
+		return strconv.FormatInt(int64(s), 10), nil
+	case uint32:
+		return strconv.FormatInt(int64(s), 10), nil
+	case uint16:
+		return strconv.FormatInt(int64(s), 10), nil
+	case uint8:
+		return strconv.FormatInt(int64(s), 10), nil
+	case []byte:
+		return string(s), nil
+	case template.HTML:
+		return string(s), nil
+	case template.URL:
+		return string(s), nil
+	case template.JS:
+		return string(s), nil
+	case template.CSS:
+		return string(s), nil
+	case template.HTMLAttr:
+		return string(s), nil
+	case nil:
+		return "", nil
+	case fmt.Stringer:
+		return s.String(), nil
+	case error:
+		return s.Error(), nil
+	default:
+		return "", fmt.Errorf("unable to cast %#v of type %T to string", i, i)
+	}
+}
+
+// ToStringMapStringE casts an interface to a map[string]string type.
+func ToStringMapStringE(i interface{}) (map[string]string, error) {
+	var m = map[string]string{}
+
+	switch v := i.(type) {
+	case map[string]string:
+		return v, nil
+	case map[string]interface{}:
+		for k, val := range v {
+			m[ToString(k)] = ToString(val)
+		}
+		return m, nil
+	case map[interface{}]string:
+		for k, val := range v {
+			m[ToString(k)] = ToString(val)
+		}
+		return m, nil
+	case map[interface{}]interface{}:
+		for k, val := range v {
+			m[ToString(k)] = ToString(val)
+		}
+		return m, nil
+	case string:
+		err := jsonStringToObject(v, &m)
+		return m, err
+	default:
+		return m, fmt.Errorf("unable to cast %#v of type %T to map[string]string", i, i)
+	}
+}
+
+// ToStringMapStringSliceE casts an interface to a map[string][]string type.
+func ToStringMapStringSliceE(i interface{}) (map[string][]string, error) {
+	var m = map[string][]string{}
+
+	switch v := i.(type) {
+	case map[string][]string:
+		return v, nil
+	case map[string][]interface{}:
+		for k, val := range v {
+			m[ToString(k)] = ToStringSlice(val)
+		}
+		return m, nil
+	case map[string]string:
+		for k, val := range v {
+			m[ToString(k)] = []string{val}
+		}
+	case map[string]interface{}:
+		for k, val := range v {
+			switch vt := val.(type) {
+			case []interface{}:
+				m[ToString(k)] = ToStringSlice(vt)
+			case []string:
+				m[ToString(k)] = vt
+			default:
+				m[ToString(k)] = []string{ToString(val)}
+			}
+		}
+		return m, nil
+	case map[interface{}][]string:
+		for k, val := range v {
+			m[ToString(k)] = ToStringSlice(val)
+		}
+		return m, nil
+	case map[interface{}]string:
+		for k, val := range v {
+			m[ToString(k)] = ToStringSlice(val)
+		}
+		return m, nil
+	case map[interface{}][]interface{}:
+		for k, val := range v {
+			m[ToString(k)] = ToStringSlice(val)
+		}
+		return m, nil
+	case map[interface{}]interface{}:
+		for k, val := range v {
+			key, err := ToStringE(k)
+			if err != nil {
+				return m, fmt.Errorf("unable to cast %#v of type %T to map[string][]string", i, i)
+			}
+			value, err := ToStringSliceE(val)
+			if err != nil {
+				return m, fmt.Errorf("unable to cast %#v of type %T to map[string][]string", i, i)
+			}
+			m[key] = value
+		}
+	case string:
+		err := jsonStringToObject(v, &m)
+		return m, err
+	default:
+		return m, fmt.Errorf("unable to cast %#v of type %T to map[string][]string", i, i)
+	}
+	return m, nil
+}
+
+// ToStringMapBoolE casts an interface to a map[string]bool type.
+func ToStringMapBoolE(i interface{}) (map[string]bool, error) {
+	var m = map[string]bool{}
+
+	switch v := i.(type) {
+	case map[interface{}]interface{}:
+		for k, val := range v {
+			m[ToString(k)] = ToBool(val)
+		}
+		return m, nil
+	case map[string]interface{}:
+		for k, val := range v {
+			m[ToString(k)] = ToBool(val)
+		}
+		return m, nil
+	case map[string]bool:
+		return v, nil
+	case string:
+		err := jsonStringToObject(v, &m)
+		return m, err
+	default:
+		return m, fmt.Errorf("unable to cast %#v of type %T to map[string]bool", i, i)
+	}
+}
+
+// ToStringMapE casts an interface to a map[string]interface{} type.
+func ToStringMapE(i interface{}) (map[string]interface{}, error) {
+	var m = map[string]interface{}{}
+
+	switch v := i.(type) {
+	case map[interface{}]interface{}:
+		for k, val := range v {
+			m[ToString(k)] = val
+		}
+		return m, nil
+	case map[string]interface{}:
+		return v, nil
+	case string:
+		err := jsonStringToObject(v, &m)
+		return m, err
+	default:
+		return m, fmt.Errorf("unable to cast %#v of type %T to map[string]interface{}", i, i)
+	}
+}
+
+// ToSliceE casts an interface to a []interface{} type.
+func ToSliceE(i interface{}) ([]interface{}, error) {
+	var s []interface{}
+
+	switch v := i.(type) {
+	case []interface{}:
+		return append(s, v...), nil
+	case []map[string]interface{}:
+		for _, u := range v {
+			s = append(s, u)
+		}
+		return s, nil
+	default:
+		return s, fmt.Errorf("unable to cast %#v of type %T to []interface{}", i, i)
+	}
+}
+
+// ToBoolSliceE casts an interface to a []bool type.
+func ToBoolSliceE(i interface{}) ([]bool, error) {
+	if i == nil {
+		return []bool{}, fmt.Errorf("unable to cast %#v of type %T to []bool", i, i)
+	}
+
+	switch v := i.(type) {
+	case []bool:
+		return v, nil
+	}
+
+	kind := reflect.TypeOf(i).Kind()
+	switch kind {
+	case reflect.Slice, reflect.Array:
+		s := reflect.ValueOf(i)
+		a := make([]bool, s.Len())
+		for j := 0; j < s.Len(); j++ {
+			val, err := ToBoolE(s.Index(j).Interface())
+			if err != nil {
+				return []bool{}, fmt.Errorf("unable to cast %#v of type %T to []bool", i, i)
+			}
+			a[j] = val
+		}
+		return a, nil
+	default:
+		return []bool{}, fmt.Errorf("unable to cast %#v of type %T to []bool", i, i)
+	}
+}
+
+// ToStringSliceE casts an interface to a []string type.
+func ToStringSliceE(i interface{}) ([]string, error) {
+	var a []string
+
+	switch v := i.(type) {
+	case []interface{}:
+		for _, u := range v {
+			a = append(a, ToString(u))
+		}
+		return a, nil
+	case []string:
+		return v, nil
+	case string:
+		return strings.Fields(v), nil
+	case interface{}:
+		str, err := ToStringE(v)
+		if err != nil {
+			return a, fmt.Errorf("unable to cast %#v of type %T to []string", i, i)
+		}
+		return []string{str}, nil
+	default:
+		return a, fmt.Errorf("unable to cast %#v of type %T to []string", i, i)
+	}
+}
+
+// ToIntSliceE casts an interface to a []int type.
+func ToIntSliceE(i interface{}) ([]int, error) {
+	if i == nil {
+		return []int{}, fmt.Errorf("unable to cast %#v of type %T to []int", i, i)
+	}
+
+	switch v := i.(type) {
+	case []int:
+		return v, nil
+	}
+
+	kind := reflect.TypeOf(i).Kind()
+	switch kind {
+	case reflect.Slice, reflect.Array:
+		s := reflect.ValueOf(i)
+		a := make([]int, s.Len())
+		for j := 0; j < s.Len(); j++ {
+			val, err := ToIntE(s.Index(j).Interface())
+			if err != nil {
+				return []int{}, fmt.Errorf("unable to cast %#v of type %T to []int", i, i)
+			}
+			a[j] = val
+		}
+		return a, nil
+	default:
+		return []int{}, fmt.Errorf("unable to cast %#v of type %T to []int", i, i)
+	}
+}
+
+// ToDurationSliceE casts an interface to a []time.Duration type.
+func ToDurationSliceE(i interface{}) ([]time.Duration, error) {
+	if i == nil {
+		return []time.Duration{}, fmt.Errorf("unable to cast %#v of type %T to []time.Duration", i, i)
+	}
+
+	switch v := i.(type) {
+	case []time.Duration:
+		return v, nil
+	}
+
+	kind := reflect.TypeOf(i).Kind()
+	switch kind {
+	case reflect.Slice, reflect.Array:
+		s := reflect.ValueOf(i)
+		a := make([]time.Duration, s.Len())
+		for j := 0; j < s.Len(); j++ {
+			val, err := ToDurationE(s.Index(j).Interface())
+			if err != nil {
+				return []time.Duration{}, fmt.Errorf("unable to cast %#v of type %T to []time.Duration", i, i)
+			}
+			a[j] = val
+		}
+		return a, nil
+	default:
+		return []time.Duration{}, fmt.Errorf("unable to cast %#v of type %T to []time.Duration", i, i)
+	}
+}
+
+// StringToDate attempts to parse a string into a time.Time type using a
+// predefined list of formats.  If no suitable format is found, an error is
+// returned.
+func StringToDate(s string) (time.Time, error) {
+	return parseDateWith(s, []string{
+		time.RFC3339,
+		"2006-01-02T15:04:05", // iso8601 without timezone
+		time.RFC1123Z,
+		time.RFC1123,
+		time.RFC822Z,
+		time.RFC822,
+		time.RFC850,
+		time.ANSIC,
+		time.UnixDate,
+		time.RubyDate,
+		"2006-01-02 15:04:05.999999999 -0700 MST", // Time.String()
+		"2006-01-02",
+		"02 Jan 2006",
+		"2006-01-02 15:04:05 -07:00",
+		"2006-01-02 15:04:05 -0700",
+		"2006-01-02 15:04:05Z07:00", // RFC3339 without T
+		"2006-01-02 15:04:05",
+		time.Kitchen,
+		time.Stamp,
+		time.StampMilli,
+		time.StampMicro,
+		time.StampNano,
+	})
+}
+
+func parseDateWith(s string, dates []string) (d time.Time, e error) {
+	for _, dateType := range dates {
+		if d, e = time.Parse(dateType, s); e == nil {
+			return
+		}
+	}
+	return d, fmt.Errorf("unable to parse date: %s", s)
+}
+
+// jsonStringToObject attempts to unmarshall a string as JSON into
+// the object passed as pointer.
+func jsonStringToObject(s string, v interface{}) error {
+	data := []byte(s)
+	return json.Unmarshal(data, v)
+}