tpl/compare: Make it a package that stands on its own

See #3042

tpl/compare/compare.go

@@ -20,11 +20,20 @@ import (
 	"time"
 )
 
+// New returns a new instance of the compare-namespaced template functions.
+func New() *Namespace {
+	return &Namespace{}
+}
+
+// Namespace provides template functions for the "compare" namespace.
+type Namespace struct {
+}
+
 // Default checks whether a given value is set and returns a default value if it
 // is not.  "Set" in this context means non-zero for numeric types and times;
 // non-zero length for strings, arrays, slices, and maps;
 // any boolean or struct value; or non-nil for any other types.
-func Default(dflt interface{}, given ...interface{}) (interface{}, error) {
+func (*Namespace) Default(dflt interface{}, given ...interface{}) (interface{}, error) {
 	// given is variadic because the following construct will not pass a piped
 	// argument when the key is missing:  {{ index . "key" | default "foo" }}
 	// The Go template will complain that we got 1 argument when we expectd 2.
@@ -75,7 +84,7 @@ func Default(dflt interface{}, given ...interface{}) (interface{}, error) {
 }
 
 // Eq returns the boolean truth of arg1 == arg2.
-func Eq(x, y interface{}) bool {
+func (*Namespace) Eq(x, y interface{}) bool {
 	normalize := func(v interface{}) interface{} {
 		vv := reflect.ValueOf(v)
 		switch vv.Kind() {
@@ -95,35 +104,35 @@ func Eq(x, y interface{}) bool {
 }
 
 // Ne returns the boolean truth of arg1 != arg2.
-func Ne(x, y interface{}) bool {
-	return !Eq(x, y)
+func (n *Namespace) Ne(x, y interface{}) bool {
+	return !n.Eq(x, y)
 }
 
 // Ge returns the boolean truth of arg1 >= arg2.
-func Ge(a, b interface{}) bool {
-	left, right := compareGetFloat(a, b)
+func (n *Namespace) Ge(a, b interface{}) bool {
+	left, right := n.compareGetFloat(a, b)
 	return left >= right
 }
 
 // Gt returns the boolean truth of arg1 > arg2.
-func Gt(a, b interface{}) bool {
-	left, right := compareGetFloat(a, b)
+func (n *Namespace) Gt(a, b interface{}) bool {
+	left, right := n.compareGetFloat(a, b)
 	return left > right
 }
 
 // Le returns the boolean truth of arg1 <= arg2.
-func Le(a, b interface{}) bool {
-	left, right := compareGetFloat(a, b)
+func (n *Namespace) Le(a, b interface{}) bool {
+	left, right := n.compareGetFloat(a, b)
 	return left <= right
 }
 
 // Lt returns the boolean truth of arg1 < arg2.
-func Lt(a, b interface{}) bool {
-	left, right := compareGetFloat(a, b)
+func (n *Namespace) Lt(a, b interface{}) bool {
+	left, right := n.compareGetFloat(a, b)
 	return left < right
 }
 
-func compareGetFloat(a interface{}, b interface{}) (float64, float64) {
+func (*Namespace) compareGetFloat(a interface{}, b interface{}) (float64, float64) {
 	var left, right float64
 	var leftStr, rightStr *string
 	av := reflect.ValueOf(a)

tpl/compare/compare_test.go

@@ -46,6 +46,7 @@ func TestDefaultFunc(t *testing.T) {
 
 	then := time.Now()
 	now := time.Now()
+	ns := New()
 
 	for i, test := range []struct {
 		dflt   interface{}
@@ -91,7 +92,7 @@ func TestDefaultFunc(t *testing.T) {
 	} {
 		errMsg := fmt.Sprintf("[%d] %v", i, test)
 
-		result, err := Default(test.dflt, test.given)
+		result, err := ns.Default(test.dflt, test.given)
 
 		require.NoError(t, err, errMsg)
 		assert.Equal(t, result, test.expect, errMsg)
@@ -101,16 +102,18 @@ func TestDefaultFunc(t *testing.T) {
 func TestCompare(t *testing.T) {
 	t.Parallel()
 
+	n := New()
+
 	for _, test := range []struct {
 		tstCompareType
 		funcUnderTest func(a, b interface{}) bool
 	}{
-		{tstGt, Gt},
-		{tstLt, Lt},
-		{tstGe, Ge},
-		{tstLe, Le},
-		{tstEq, Eq},
-		{tstNe, Ne},
+		{tstGt, n.Gt},
+		{tstLt, n.Lt},
+		{tstGe, n.Ge},
+		{tstLe, n.Le},
+		{tstEq, n.Eq},
+		{tstNe, n.Ne},
 	} {
 		doTestCompare(t, test.tstCompareType, test.funcUnderTest)
 	}

tpl/compare/init.go

@@ -0,0 +1,49 @@
+// Copyright 2017 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
+
+import (
+	"github.com/spf13/hugo/deps"
+	"github.com/spf13/hugo/tpl/internal"
+)
+
+const name = "compare"
+
+func init() {
+	f := func(d *deps.Deps) *internal.TemplateFuncsNamespace {
+		ctx := New()
+
+		examples := [][2]string{
+			{`eq: {{ if eq .Section "blog" }}current{{ end }}`, `eq: current`},
+		}
+
+		return &internal.TemplateFuncsNamespace{
+			Name:    name,
+			Context: func() interface{} { return ctx },
+			Aliases: map[string]interface{}{
+				"default": ctx.Default,
+				"eq":      ctx.Eq,
+				"ge":      ctx.Ge,
+				"gt":      ctx.Gt,
+				"le":      ctx.Le,
+				"lt":      ctx.Lt,
+				"ne":      ctx.Ne,
+			},
+			Examples: examples,
+		}
+
+	}
+
+	internal.AddTemplateFuncsNamespace(f)
+}