mirror of
https://github.com/gohugoio/hugo.git
synced 2024-07-02 14:17:34 +00:00
58 lines
1.6 KiB
Go
58 lines
1.6 KiB
Go
// Copyright 2018 The Hugo Authors. All rights reserved.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package collections
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
"reflect"
|
|
)
|
|
|
|
// Complement gives the elements in the last element of ls that are not in
|
|
// any of the others.
|
|
//
|
|
// All elements of ls must be slices or arrays of comparable types.
|
|
//
|
|
// The reasoning behind this rather clumsy API is so we can do this in the templates:
|
|
//
|
|
// {{ $c := .Pages | complement $last4 }}
|
|
func (ns *Namespace) Complement(ls ...any) (any, error) {
|
|
if len(ls) < 2 {
|
|
return nil, errors.New("complement needs at least two arguments")
|
|
}
|
|
|
|
universe := ls[len(ls)-1]
|
|
as := ls[:len(ls)-1]
|
|
|
|
aset, err := collectIdentities(as...)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
v := reflect.ValueOf(universe)
|
|
switch v.Kind() {
|
|
case reflect.Array, reflect.Slice:
|
|
sl := reflect.MakeSlice(v.Type(), 0, 0)
|
|
for i := 0; i < v.Len(); i++ {
|
|
ev, _ := indirectInterface(v.Index(i))
|
|
if _, found := aset[normalize(ev)]; !found {
|
|
sl = reflect.Append(sl, ev)
|
|
}
|
|
}
|
|
return sl.Interface(), nil
|
|
default:
|
|
return nil, fmt.Errorf("arguments to complement must be slices or arrays")
|
|
}
|
|
}
|