hugo/hugolib/pages_language_merge.go
Bjørn Erik Pedersen ffaec4ca8c
Add a way to merge pages by language
As an example:

```html
{{ $pages := .Site.RegularPages | lang.Merge $frSite.RegularPages | lang.Merge $enSite.RegularPages }}
```

Will "fill in the gaps" in the current site with, from left to right, content from the French site, and lastly the English.

Fixes #4463
2018-03-16 10:10:01 +01:00

62 lines
1.7 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 hugolib
import (
"fmt"
)
var (
_ pagesLanguageMerger = (*Pages)(nil)
)
type pagesLanguageMerger interface {
MergeByLanguage(other Pages) Pages
// Needed for integration with the tpl package.
MergeByLanguageInterface(other interface{}) (interface{}, error)
}
// MergeByLanguage supplies missing translations in p1 with values from p2.
// The result is sorted by the default sort order for pages.
func (p1 Pages) MergeByLanguage(p2 Pages) Pages {
merge := func(pages *Pages) {
m := make(map[string]bool)
for _, p := range *pages {
m[p.TranslationKey()] = true
}
for _, p := range p2 {
if _, found := m[p.TranslationKey()]; !found {
*pages = append(*pages, p)
}
}
pages.Sort()
}
out, _ := spc.getP("pages.MergeByLanguage", merge, p1, p2)
return out
}
// MergeByLanguageInterface is the generic version of MergeByLanguage. It
// is here just so it can be called from the tpl package.
func (p1 Pages) MergeByLanguageInterface(in interface{}) (interface{}, error) {
p2, ok := in.(Pages)
if !ok {
return nil, fmt.Errorf("%T cannot be merged by language", in)
}
return p1.MergeByLanguage(p2), nil
}