zerica
/
hugo
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Add writable context to Node 

The variable scope in the Go templates makes it hard, if possible at all, to write templates with counter variables or similar state.

This commit fixes that by adding a writable context to Node, backed by a map: Scratch.

This context has three methods, Get, Set and Add. The Add is tailored for counter variables, but can be used for any built-in numeric values or strings.
This commit is contained in:
bep 2014-12-26 21:18:26 +01:00
parent 47c8f32967
commit 420c9e4d3d
6 changed files with 327 additions and 88 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

123
helpers/general.go
View File

@ -17,10 +17,12 @@ import (
"bytes"
"crypto/md5"
"encoding/hex"
"errors"
"fmt"
"io"
"net"
"path/filepath"
"reflect"
"strings"
bp "github.com/spf13/hugo/bufferpool"
@ -118,3 +120,124 @@ func Md5String(f string) string {
h.Write([]byte(f))
return hex.EncodeToString(h.Sum([]byte{}))
}
// DoArithmetic performs arithmetic operations (+,-,*,/) using reflection to
// determine the type of the two terms.
func DoArithmetic(a, b interface{}, op rune) (interface{}, error) {
av := reflect.ValueOf(a)
bv := reflect.ValueOf(b)
var ai, bi int64
var af, bf float64
var au, bu uint64
switch av.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
ai = av.Int()
switch bv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
bi = bv.Int()
case reflect.Float32, reflect.Float64:
af = float64(ai) // may overflow
ai = 0
bf = bv.Float()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
bu = bv.Uint()
if ai >= 0 {
au = uint64(ai)
ai = 0
} else {
bi = int64(bu) // may overflow
bu = 0
}
default:
return nil, errors.New("Can't apply the operator to the values")
}
case reflect.Float32, reflect.Float64:
af = av.Float()
switch bv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
bf = float64(bv.Int()) // may overflow
case reflect.Float32, reflect.Float64:
bf = bv.Float()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
bf = float64(bv.Uint()) // may overflow
default:
return nil, errors.New("Can't apply the operator to the values")
}
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
au = av.Uint()
switch bv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
bi = bv.Int()
if bi >= 0 {
bu = uint64(bi)
bi = 0
} else {
ai = int64(au) // may overflow
au = 0
}
case reflect.Float32, reflect.Float64:
af = float64(au) // may overflow
au = 0
bf = bv.Float()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
bu = bv.Uint()
default:
return nil, errors.New("Can't apply the operator to the values")
}
case reflect.String:
as := av.String()
if bv.Kind() == reflect.String && op == '+' {
bs := bv.String()
return as + bs, nil
} else {
return nil, errors.New("Can't apply the operator to the values")
}
default:
return nil, errors.New("Can't apply the operator to the values")
}
switch op {
case '+':
if ai != 0 || bi != 0 {
return ai + bi, nil
} else if af != 0 || bf != 0 {
return af + bf, nil
} else if au != 0 || bu != 0 {
return au + bu, nil
} else {
return 0, nil
}
case '-':
if ai != 0 || bi != 0 {
return ai - bi, nil
} else if af != 0 || bf != 0 {
return af - bf, nil
} else if au != 0 || bu != 0 {
return au - bu, nil
} else {
return 0, nil
}
case '*':
if ai != 0 || bi != 0 {
return ai * bi, nil
} else if af != 0 || bf != 0 {
return af * bf, nil
} else if au != 0 || bu != 0 {
return au * bu, nil
} else {
return 0, nil
}
case '/':
if bi != 0 {
return ai / bi, nil
} else if bf != 0 {
return af / bf, nil
} else if bu != 0 {
return au / bu, nil
} else {
return nil, errors.New("Can't divide the value by 0")
}
default:
return nil, errors.New("There is no such an operation")
}
}

89
helpers/general_test.go
View File

@ -2,6 +2,7 @@ package helpers
import (
"github.com/stretchr/testify/assert"
"reflect"
"strings"
"testing"
)
@ -128,3 +129,91 @@ func TestMd5StringEmpty(t *testing.T) {
Md5String(in)
}
}
func TestDoArithmetic(t *testing.T) {
for i, this := range []struct {
a interface{}
b interface{}
op rune
expect interface{}
}{
{3, 2, '+', int64(5)},
{3, 2, '-', int64(1)},
{3, 2, '*', int64(6)},
{3, 2, '/', int64(1)},
{3.0, 2, '+', float64(5)},
{3.0, 2, '-', float64(1)},
{3.0, 2, '*', float64(6)},
{3.0, 2, '/', float64(1.5)},
{3, 2.0, '+', float64(5)},
{3, 2.0, '-', float64(1)},
{3, 2.0, '*', float64(6)},
{3, 2.0, '/', float64(1.5)},
{3.0, 2.0, '+', float64(5)},
{3.0, 2.0, '-', float64(1)},
{3.0, 2.0, '*', float64(6)},
{3.0, 2.0, '/', float64(1.5)},
{uint(3), uint(2), '+', uint64(5)},
{uint(3), uint(2), '-', uint64(1)},
{uint(3), uint(2), '*', uint64(6)},
{uint(3), uint(2), '/', uint64(1)},
{uint(3), 2, '+', uint64(5)},
{uint(3), 2, '-', uint64(1)},
{uint(3), 2, '*', uint64(6)},
{uint(3), 2, '/', uint64(1)},
{3, uint(2), '+', uint64(5)},
{3, uint(2), '-', uint64(1)},
{3, uint(2), '*', uint64(6)},
{3, uint(2), '/', uint64(1)},
{uint(3), -2, '+', int64(1)},
{uint(3), -2, '-', int64(5)},
{uint(3), -2, '*', int64(-6)},
{uint(3), -2, '/', int64(-1)},
{-3, uint(2), '+', int64(-1)},
{-3, uint(2), '-', int64(-5)},
{-3, uint(2), '*', int64(-6)},
{-3, uint(2), '/', int64(-1)},
{uint(3), 2.0, '+', float64(5)},
{uint(3), 2.0, '-', float64(1)},
{uint(3), 2.0, '*', float64(6)},
{uint(3), 2.0, '/', float64(1.5)},
{3.0, uint(2), '+', float64(5)},
{3.0, uint(2), '-', float64(1)},
{3.0, uint(2), '*', float64(6)},
{3.0, uint(2), '/', float64(1.5)},
{0, 0, '+', 0},
{0, 0, '-', 0},
{0, 0, '*', 0},
{"foo", "bar", '+', "foobar"},
{3, 0, '/', false},
{3.0, 0, '/', false},
{3, 0.0, '/', false},
{uint(3), uint(0), '/', false},
{3, uint(0), '/', false},
{-3, uint(0), '/', false},
{uint(3), 0, '/', false},
{3.0, uint(0), '/', false},
{uint(3), 0.0, '/', false},
{3, "foo", '+', false},
{3.0, "foo", '+', false},
{uint(3), "foo", '+', false},
{"foo", 3, '+', false},
{"foo", "bar", '-', false},
{3, 2, '%', false},
} {
result, err := DoArithmetic(this.a, this.b, this.op)
if b, ok := this.expect.(bool); ok && !b {
if err == nil {
t.Errorf("[%d] doArithmetic didn't return an expected error")
}
} else {
if err != nil {
t.Errorf("[%d] failed: %s", i, err)
continue
}
if !reflect.DeepEqual(result, this.expect) {
t.Errorf("[%d] doArithmetic got %v but expected %v", i, result, this.expect)
}
}
}
}

9
hugolib/node.go
View File

@ -33,6 +33,7 @@ type Node struct {
UrlPath
paginator *pager
paginatorInit sync.Once
scratch *Scratch
}
func (n *Node) Now() time.Time {
@ -124,3 +125,11 @@ type UrlPath struct {
Slug string
Section string
}
// Scratch returns the writable context associated with this Node.
func (n *Node) Scratch() *Scratch {
if n.scratch == nil {
n.scratch = newScratch()
}
return n.scratch
}

57
hugolib/scratch.go Normal file
View File

@ -0,0 +1,57 @@
// Copyright © 2013-14 Steve Francia <spf@spf13.com>.
//
// Licensed under the Simple Public 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://opensource.org/licenses/Simple-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 (
"github.com/spf13/hugo/helpers"
)
// Scratch is a writable context used for stateful operations in Page/Node rendering.
type Scratch struct {
values map[string]interface{}
}
// Add will add (using the + operator) the addend to the existing addend (if found).
// Supports numeric values and strings.
func (c *Scratch) Add(key string, newAddend interface{}) (string, error) {
var newVal interface{}
existingAddend, found := c.values[key]
if found {
var err error
newVal, err = helpers.DoArithmetic(existingAddend, newAddend, '+')
if err != nil {
return "", err
}
} else {
newVal = newAddend
}
c.values[key] = newVal
return "", nil // have to return something to make it work with the Go templates
}
// Set stores a value with the given key in the Node context.
// This value can later be retrieved with Get.
func (c *Scratch) Set(key string, value interface{}) string {
c.values[key] = value
return ""
}
// Get returns a value previously set by Add or Set
func (c *Scratch) Get(key string) interface{} {
return c.values[key]
}
func newScratch() *Scratch {
return &Scratch{values: make(map[string]interface{})}
}

49
hugolib/scratch_test.go Normal file
View File

@ -0,0 +1,49 @@
package hugolib
import (
"github.com/stretchr/testify/assert"
"testing"
)
func TestScratchAdd(t *testing.T) {
scratch := newScratch()
scratch.Add("int1", 10)
scratch.Add("int1", 20)
scratch.Add("int2", 20)
assert.Equal(t, 30, scratch.Get("int1"))
assert.Equal(t, 20, scratch.Get("int2"))
scratch.Add("float1", float64(10.5))
scratch.Add("float1", float64(20.1))
assert.Equal(t, float64(30.6), scratch.Get("float1"))
scratch.Add("string1", "Hello ")
scratch.Add("string1", "big ")
scratch.Add("string1", "World!")
assert.Equal(t, "Hello big World!", scratch.Get("string1"))
scratch.Add("scratch", scratch)
_, err := scratch.Add("scratch", scratch)
if err == nil {
t.Errorf("Expected error from invalid arithmetic")
}
}
func TestScratchSet(t *testing.T) {
scratch := newScratch()
scratch.Set("key", "val")
assert.Equal(t, "val", scratch.Get("key"))
}
func TestScratchGet(t *testing.T) {
scratch := newScratch()
nothing := scratch.Get("nothing")
if nothing != nil {
t.Errorf("Should not return anything, but got %v", nothing)
}
}

88
tpl/template_test.go
View File

@ -101,94 +101,6 @@ func doTestCompare(t *testing.T, tp tstCompareType, funcUnderTest func(a, b inte
}
}
func TestDoArithmetic(t *testing.T) {
for i, this := range []struct {
a interface{}
b interface{}
op rune
expect interface{}
}{
{3, 2, '+', int64(5)},
{3, 2, '-', int64(1)},
{3, 2, '*', int64(6)},
{3, 2, '/', int64(1)},
{3.0, 2, '+', float64(5)},
{3.0, 2, '-', float64(1)},
{3.0, 2, '*', float64(6)},
{3.0, 2, '/', float64(1.5)},
{3, 2.0, '+', float64(5)},
{3, 2.0, '-', float64(1)},
{3, 2.0, '*', float64(6)},
{3, 2.0, '/', float64(1.5)},
{3.0, 2.0, '+', float64(5)},
{3.0, 2.0, '-', float64(1)},
{3.0, 2.0, '*', float64(6)},
{3.0, 2.0, '/', float64(1.5)},
{uint(3), uint(2), '+', uint64(5)},
{uint(3), uint(2), '-', uint64(1)},
{uint(3), uint(2), '*', uint64(6)},
{uint(3), uint(2), '/', uint64(1)},
{uint(3), 2, '+', uint64(5)},
{uint(3), 2, '-', uint64(1)},
{uint(3), 2, '*', uint64(6)},
{uint(3), 2, '/', uint64(1)},
{3, uint(2), '+', uint64(5)},
{3, uint(2), '-', uint64(1)},
{3, uint(2), '*', uint64(6)},
{3, uint(2), '/', uint64(1)},
{uint(3), -2, '+', int64(1)},
{uint(3), -2, '-', int64(5)},
{uint(3), -2, '*', int64(-6)},
{uint(3), -2, '/', int64(-1)},
{-3, uint(2), '+', int64(-1)},
{-3, uint(2), '-', int64(-5)},
{-3, uint(2), '*', int64(-6)},
{-3, uint(2), '/', int64(-1)},
{uint(3), 2.0, '+', float64(5)},
{uint(3), 2.0, '-', float64(1)},
{uint(3), 2.0, '*', float64(6)},
{uint(3), 2.0, '/', float64(1.5)},
{3.0, uint(2), '+', float64(5)},
{3.0, uint(2), '-', float64(1)},
{3.0, uint(2), '*', float64(6)},
{3.0, uint(2), '/', float64(1.5)},
{0, 0, '+', 0},
{0, 0, '-', 0},
{0, 0, '*', 0},
{"foo", "bar", '+', "foobar"},
{3, 0, '/', false},
{3.0, 0, '/', false},
{3, 0.0, '/', false},
{uint(3), uint(0), '/', false},
{3, uint(0), '/', false},
{-3, uint(0), '/', false},
{uint(3), 0, '/', false},
{3.0, uint(0), '/', false},
{uint(3), 0.0, '/', false},
{3, "foo", '+', false},
{3.0, "foo", '+', false},
{uint(3), "foo", '+', false},
{"foo", 3, '+', false},
{"foo", "bar", '-', false},
{3, 2, '%', false},
} {
result, err := doArithmetic(this.a, this.b, this.op)
if b, ok := this.expect.(bool); ok && !b {
if err == nil {
t.Errorf("[%d] doArithmetic didn't return an expected error", i)
}
} else {
if err != nil {
t.Errorf("[%d] failed: %s", i, err)
continue
}
if !reflect.DeepEqual(result, this.expect) {
t.Errorf("[%d] doArithmetic got %v but expected %v", i, result, this.expect)
}
}
}
}
func TestMod(t *testing.T) {
for i, this := range []struct {
a interface{}