slice.go (1937B)
1 // Copyright 2018 The Hugo Authors. All rights reserved.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 // http://www.apache.org/licenses/LICENSE-2.0
7 //
8 // Unless required by applicable law or agreed to in writing, software
9 // distributed under the License is distributed on an "AS IS" BASIS,
10 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 // See the License for the specific language governing permissions and
12 // limitations under the License.
13
14 package collections
15
16 import (
17 "reflect"
18 )
19
20 // Slicer defines a very generic way to create a typed slice. This is used
21 // in collections.Slice template func to get types such as Pages, PageGroups etc.
22 // instead of the less useful []interface{}.
23 type Slicer interface {
24 Slice(items any) (any, error)
25 }
26
27 // Slice returns a slice of all passed arguments.
28 func Slice(args ...any) any {
29 if len(args) == 0 {
30 return args
31 }
32
33 first := args[0]
34 firstType := reflect.TypeOf(first)
35
36 if firstType == nil {
37 return args
38 }
39
40 if g, ok := first.(Slicer); ok {
41 v, err := g.Slice(args)
42 if err == nil {
43 return v
44 }
45
46 // If Slice fails, the items are not of the same type and
47 // []interface{} is the best we can do.
48 return args
49 }
50
51 if len(args) > 1 {
52 // This can be a mix of types.
53 for i := 1; i < len(args); i++ {
54 if firstType != reflect.TypeOf(args[i]) {
55 // []interface{} is the best we can do
56 return args
57 }
58 }
59 }
60
61 slice := reflect.MakeSlice(reflect.SliceOf(firstType), len(args), len(args))
62 for i, arg := range args {
63 slice.Index(i).Set(reflect.ValueOf(arg))
64 }
65 return slice.Interface()
66 }
67
68 // StringSliceToInterfaceSlice converts ss to []interface{}.
69 func StringSliceToInterfaceSlice(ss []string) []any {
70 result := make([]any, len(ss))
71 for i, s := range ss {
72 result[i] = s
73 }
74 return result
75
76 }