slice.go•1.87 kB
// 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 (
"fmt"
"reflect"
"strings"
)
// ToSliceE casts any value to a []any type.
func ToSliceE(i any) ([]any, error) {
i, _ = indirect(i)
var s []any
switch v := i.(type) {
case []any:
// TODO: use slices.Clone
return append(s, v...), nil
case []map[string]any:
for _, u := range v {
s = append(s, u)
}
return s, nil
default:
return s, fmt.Errorf(errorMsg, i, i, s)
}
}
func toSliceE[T Basic](i any) ([]T, error) {
v, ok, err := toSliceEOk[T](i)
if err != nil {
return nil, err
}
if !ok {
return nil, fmt.Errorf(errorMsg, i, i, []T{})
}
return v, nil
}
func toSliceEOk[T Basic](i any) ([]T, bool, error) {
i, _ = indirect(i)
if i == nil {
return nil, true, fmt.Errorf(errorMsg, i, i, []T{})
}
switch v := i.(type) {
case []T:
// TODO: clone slice
return v, true, nil
}
kind := reflect.TypeOf(i).Kind()
switch kind {
case reflect.Slice, reflect.Array:
s := reflect.ValueOf(i)
a := make([]T, s.Len())
for j := 0; j < s.Len(); j++ {
val, err := ToE[T](s.Index(j).Interface())
if err != nil {
return nil, true, fmt.Errorf(errorMsg, i, i, []T{})
}
a[j] = val
}
return a, true, nil
default:
return nil, false, nil
}
}
// ToStringSliceE casts any value to a []string type.
func ToStringSliceE(i any) ([]string, error) {
if a, ok, err := toSliceEOk[string](i); ok {
if err != nil {
return nil, err
}
return a, nil
}
var a []string
switch v := i.(type) {
case string:
return strings.Fields(v), nil
case any:
str, err := ToStringE(v)
if err != nil {
return nil, fmt.Errorf(errorMsg, i, i, a)
}
return []string{str}, nil
default:
return nil, fmt.Errorf(errorMsg, i, i, a)
}
}