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https://github.com/gohugoio/hugo.git
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e27fd4c1b8
Before this commit you would typically use `.Scratch.Add` to manually create slices in a loop.
With variable overwrite in Go 1.11, we can do better. This commit adds the `append` template func.
A made-up example:
```bash
{{ $p1 := index .Site.RegularPages 0 }}{{ $p2 := index .Site.RegularPages 1 }}
{{ $pages := slice }}
{{ if true }}
{{ $pages = $pages | append $p2 $p1 }}
{{ end }}
```
Note that with 2 slices as arguments, the two examples below will give the same result:
```bash
{{ $s1 := slice "a" "b" | append (slice "c" "d") }}
{{ $s2 := slice "a" "b" | append "c" "d" }}
```
Both of the above will give `[]string{a, b, c, d}`.
This commit also improves the type handling in the `slice` template function. Now `slice "a" "b"` will give a `[]string` slice. The old behaviour was to return a `[]interface{}`.
Fixes #5190
75 lines
2.1 KiB
Go
75 lines
2.1 KiB
Go
// Copyright 2018 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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// Append appends the arguments up to the last one to the slice in the last argument.
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// This construct allows template constructs like this:
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// {{ $pages = $pages | append $p2 $p1 }}
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// Note that with 2 arguments where both are slices of the same type,
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// the first slice will be appended to the second:
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// {{ $pages = $pages | append .Site.RegularPages }}
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func (ns *Namespace) Append(args ...interface{}) (interface{}, error) {
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if len(args) < 2 {
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return nil, errors.New("need at least 2 arguments to append")
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}
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to := args[len(args)-1]
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from := args[:len(args)-1]
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tov, toIsNil := indirect(reflect.ValueOf(to))
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toIsNil = toIsNil || to == nil
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var tot reflect.Type
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if !toIsNil {
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if tov.Kind() != reflect.Slice {
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return nil, fmt.Errorf("expected a slice, got %T", to)
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}
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tot = tov.Type().Elem()
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toIsNil = tov.Len() == 0
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if len(from) == 1 {
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// If we get []string []string, we append the from slice to to
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fromv := reflect.ValueOf(from[0])
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if fromv.Kind() == reflect.Slice {
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fromt := reflect.TypeOf(from[0]).Elem()
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if tot == fromt {
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return reflect.AppendSlice(tov, fromv).Interface(), nil
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}
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}
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}
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}
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if toIsNil {
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return ns.Slice(from...), nil
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}
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for _, f := range from {
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fv := reflect.ValueOf(f)
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if tot != fv.Type() {
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return nil, fmt.Errorf("append element type mismatch: expected %v, got %v", tot, fv.Type())
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}
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tov = reflect.Append(tov, fv)
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}
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return tov.Interface(), nil
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}
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