Add after template function

Where `first` will return the first N items of a rangeable list,
`after` will return all items after the Nth item.

This allows the user to do something with the first N items and
something different with the remaining items after N.
This commit is contained in:
Ariejan de Vroom 2015-06-10 23:49:55 +02:00 committed by Bjørn Erik Pedersen
parent 82cc1ac0f8
commit c335efdd06
2 changed files with 74 additions and 2 deletions

View file

@ -177,7 +177,7 @@ func Substr(a interface{}, nums ...interface{}) (string, error) {
}
var start, length int
toInt := func (v interface{}, message string) (int, error) {
toInt := func(v interface{}, message string) (int, error) {
switch i := v.(type) {
case int:
return i, nil
@ -388,6 +388,42 @@ func First(limit interface{}, seq interface{}) (interface{}, error) {
return seqv.Slice(0, limitv).Interface(), nil
}
// After is exposed to templates, to iterate over all the items after N in a
// rangeable list. It's meant to accompany First
func After(limit interface{}, seq interface{}) (interface{}, error) {
if limit == nil || seq == nil {
return nil, errors.New("both limit and seq must be provided")
}
limitv, err := cast.ToIntE(limit)
if err != nil {
return nil, err
}
if limitv < 1 {
return nil, errors.New("can't return negative/empty count of items from sequence")
}
seqv := reflect.ValueOf(seq)
seqv, isNil := indirect(seqv)
if isNil {
return nil, errors.New("can't iterate over a nil value")
}
switch seqv.Kind() {
case reflect.Array, reflect.Slice, reflect.String:
// okay
default:
return nil, errors.New("can't iterate over " + reflect.ValueOf(seq).Type().String())
}
if limitv >= seqv.Len() {
return nil, errors.New("no items left")
}
return seqv.Slice(limitv, seqv.Len()).Interface(), nil
}
var (
zero reflect.Value
errorType = reflect.TypeOf((*error)(nil)).Elem()
@ -1252,6 +1288,7 @@ func init() {
"relURL": func(a string) template.HTML { return template.HTML(helpers.RelURL(a)) },
"markdownify": Markdownify,
"first": First,
"after": After,
"where": Where,
"delimit": Delimit,
"sort": Sort,

View file

@ -4,13 +4,14 @@ import (
"bytes"
"errors"
"fmt"
"github.com/stretchr/testify/assert"
"html/template"
"path"
"reflect"
"runtime"
"testing"
"time"
"github.com/stretchr/testify/assert"
)
type tstNoStringer struct {
@ -252,6 +253,40 @@ func TestFirst(t *testing.T) {
}
}
func TestAfter(t *testing.T) {
for i, this := range []struct {
count interface{}
sequence interface{}
expect interface{}
}{
{int(2), []string{"a", "b", "c", "d"}, []string{"c", "d"}},
{int32(3), []string{"a", "b"}, false},
{int64(2), []int{100, 200, 300}, []int{300}},
{100, []int{100, 200}, false},
{"1", []int{100, 200, 300}, []int{200, 300}},
{int64(-1), []int{100, 200, 300}, false},
{"noint", []int{100, 200, 300}, false},
{1, nil, false},
{nil, []int{100}, false},
{1, t, false},
} {
results, err := After(this.count, this.sequence)
if b, ok := this.expect.(bool); ok && !b {
if err == nil {
t.Errorf("[%d] First didn't return an expected error", i)
}
} else {
if err != nil {
t.Errorf("[%d] failed: %s", i, err)
continue
}
if !reflect.DeepEqual(results, this.expect) {
t.Errorf("[%d] First %d items, got %v but expected %v", i, this.count, results, this.expect)
}
}
}
}
func TestIn(t *testing.T) {
for i, this := range []struct {
v1 interface{}