mirror of
https://github.com/gohugoio/hugo.git
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de7c32a1a8
This commit moves almost all of the template functions into separate packages under tpl/ and adds a namespace framework. All changes should be backward compatible for end users, as all existing function names in the template funcMap are left intact. Seq and DoArithmatic have been moved out of the helpers package and into template namespaces. Most of the tests involved have been refactored, and many new tests have been written. There's still work to do, but this is a big improvement. I got a little overzealous and added some new functions along the way: - strings.Contains - strings.ContainsAny - strings.HasSuffix - strings.TrimPrefix - strings.TrimSuffix Documentation is forthcoming. Fixes #3042
108 lines
3.4 KiB
Go
108 lines
3.4 KiB
Go
// Copyright 2017 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package collections
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import (
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"errors"
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"fmt"
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"reflect"
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)
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// Index returns the result of indexing its first argument by the following
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// arguments. Thus "index x 1 2 3" is, in Go syntax, x[1][2][3]. Each
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// indexed item must be a map, slice, or array.
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//
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// Copied from Go stdlib src/text/template/funcs.go.
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//
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// We deviate from the stdlib due to https://github.com/golang/go/issues/14751.
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//
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// TODO(moorereason): merge upstream changes.
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func (ns *Namespace) Index(item interface{}, indices ...interface{}) (interface{}, error) {
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v := reflect.ValueOf(item)
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if !v.IsValid() {
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return nil, errors.New("index of untyped nil")
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}
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for _, i := range indices {
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index := reflect.ValueOf(i)
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var isNil bool
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if v, isNil = indirect(v); isNil {
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return nil, errors.New("index of nil pointer")
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}
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switch v.Kind() {
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case reflect.Array, reflect.Slice, reflect.String:
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var x int64
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switch index.Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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x = index.Int()
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case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
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x = int64(index.Uint())
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case reflect.Invalid:
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return nil, errors.New("cannot index slice/array with nil")
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default:
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return nil, fmt.Errorf("cannot index slice/array with type %s", index.Type())
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}
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if x < 0 || x >= int64(v.Len()) {
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// We deviate from stdlib here. Don't return an error if the
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// index is out of range.
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return nil, nil
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}
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v = v.Index(int(x))
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case reflect.Map:
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index, err := prepareArg(index, v.Type().Key())
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if err != nil {
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return nil, err
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}
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if x := v.MapIndex(index); x.IsValid() {
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v = x
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} else {
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v = reflect.Zero(v.Type().Elem())
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}
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case reflect.Invalid:
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// the loop holds invariant: v.IsValid()
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panic("unreachable")
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default:
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return nil, fmt.Errorf("can't index item of type %s", v.Type())
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}
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}
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return v.Interface(), nil
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}
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// prepareArg checks if value can be used as an argument of type argType, and
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// converts an invalid value to appropriate zero if possible.
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//
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// Copied from Go stdlib src/text/template/funcs.go.
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func prepareArg(value reflect.Value, argType reflect.Type) (reflect.Value, error) {
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if !value.IsValid() {
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if !canBeNil(argType) {
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return reflect.Value{}, fmt.Errorf("value is nil; should be of type %s", argType)
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}
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value = reflect.Zero(argType)
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}
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if !value.Type().AssignableTo(argType) {
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return reflect.Value{}, fmt.Errorf("value has type %s; should be %s", value.Type(), argType)
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}
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return value, nil
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}
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// canBeNil reports whether an untyped nil can be assigned to the type. See reflect.Zero.
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//
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// Copied from Go stdlib src/text/template/exec.go.
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func canBeNil(typ reflect.Type) bool {
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switch typ.Kind() {
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case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
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return true
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}
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return false
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}
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