compare, hugolib, tpl: Add Eqer interface

And use it in `eq` and `ne` so `Page` values can be compared directly in the templates without thinking about it being a `Page` or a `PageOutput` wrapper.

Fixes #3807
This commit is contained in:
Bjørn Erik Pedersen 2017-08-17 10:24:17 +02:00
parent 2fc121ce23
commit 08f48b91d6
4 changed files with 59 additions and 0 deletions

21
compare/eq.go Normal file
View file

@ -0,0 +1,21 @@
// Copyright 2017-present 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 compare
// Eqer can be used to determine if this value is equal to the other.
// The semantics of equals is that the two value are interchangeable
// in the Hugo templates.
type Eqer interface {
Eq(other interface{}) bool
}

View file

@ -38,6 +38,7 @@ import (
"unicode/utf8"
bp "github.com/gohugoio/hugo/bufferpool"
"github.com/gohugoio/hugo/compare"
"github.com/gohugoio/hugo/source"
"github.com/spf13/cast"
)
@ -49,6 +50,10 @@ var (
allKindsInPages = []string{KindPage, KindHome, KindSection, KindTaxonomy, KindTaxonomyTerm}
allKinds = append(allKindsInPages, []string{kindRSS, kindSitemap, kindRobotsTXT, kind404}...)
// Assert that it implements the Eqer interface.
_ compare.Eqer = (*Page)(nil)
_ compare.Eqer = (*PageOutput)(nil)
)
const (

View file

@ -18,6 +18,8 @@ import (
"reflect"
"strconv"
"time"
"github.com/gohugoio/hugo/compare"
)
// New returns a new instance of the compare-namespaced template functions.
@ -85,6 +87,14 @@ func (*Namespace) Default(dflt interface{}, given ...interface{}) (interface{},
// Eq returns the boolean truth of arg1 == arg2.
func (*Namespace) Eq(x, y interface{}) bool {
// hugolib.Page implements compare.Eqer to make Page and PageOutput comparable.
if e1, ok := x.(compare.Eqer); ok {
if e2, ok := y.(compare.Eqer); ok {
return e1.Eq(e2)
}
}
normalize := func(v interface{}) interface{} {
vv := reflect.ValueOf(v)
switch vv.Kind() {

View file

@ -26,6 +26,25 @@ import (
"github.com/stretchr/testify/require"
)
type tstEqerType1 string
type tstEqerType2 string
func (t tstEqerType2) Eq(other interface{}) bool {
return cast.ToString(t) == cast.ToString(other)
}
func (t tstEqerType2) String() string {
return string(t)
}
func (t tstEqerType1) Eq(other interface{}) bool {
return cast.ToString(t) == cast.ToString(other)
}
func (t tstEqerType1) String() string {
return string(t)
}
type tstCompareType int
const (
@ -148,6 +167,10 @@ func doTestCompare(t *testing.T, tp tstCompareType, funcUnderTest func(a, b inte
{"a", "a", 0},
{"a", "b", -1},
{"b", "a", 1},
{tstEqerType1("a"), tstEqerType1("a"), 0},
{tstEqerType1("a"), tstEqerType2("a"), 0},
{tstEqerType2("a"), tstEqerType1("a"), 0},
{tstEqerType2("a"), tstEqerType1("b"), -1},
} {
result := funcUnderTest(test.left, test.right)
success := false