Element.Create

[3052]

Element should have a Create method or similar, to allow for more natural creation of nested values

doc := NewDocument()
doc.Create("People", func(e *Element) {
   e.Create("Person", func(e *Element) {
      e.CreateAttr("name", "Jon")
   })
   e.Create("Person", func(e *Element) {
      e.CreateAttr("name", "Sally")
   })
})

[3052]

implementation

package etree

func (e *Element) Create(tag string, f func(*Element)) {
   f(e.CreateElement(tag))
}

[3052]

in case this is not accepted, here is a wrapper:

package etree

import "github.com/beevik/etree"

type Document struct {
   *etree.Document
}

func NewDocument() *Document {
   var d Document
   d.Document = etree.NewDocument()
   return &d
}

func (d Document) Element() *Element {
   return &Element{&d.Document.Element}
}

type Element struct {
   *etree.Element
}

func (e *Element) Create(tag string, f func(*Element)) {
   f(&Element{
      e.Element.CreateElement(tag),
   })
}

[beevik]

While I understand the motivation for this feature, I'm not sure I agree that the package demands a new API for creating elements and attributes. Your approach is essentially syntactic sugar for the existing API, which doesn't directly support a "nested" style of element creation. I think I prefer keeping the API surfaces concise so there is less ambiguity in how to do things.

[3052]

that's a shame. I modeled the example above from here:

https://github.com/beevik/etree#creating-an-xml-document

but instead of four top level declarations:

doc
jon
people
sally

you have one:

doc

also note I modeled this pattern from packages in golang.org/x:

• https://golang.org/x/crypto/cryptobyte#Builder.AddASN1
• https://golang.org/x/crypto/cryptobyte#Builder.AddUint16LengthPrefixed
• https://golang.org/x/crypto/cryptobyte#Builder.AddUint24LengthPrefixed
• https://golang.org/x/crypto/cryptobyte#Builder.AddUint32LengthPrefixed
• https://golang.org/x/crypto/cryptobyte#Builder.AddUint8LengthPrefixed
• https://golang.org/x/tools/gopls/internal/golang/completion/snippet#Builder.WritePlaceholder

[beevik]

After giving it more thought (and seeing the precedent you described in x/crypto) I've decided to go ahead and add your proposed API. It's currently visible in this branch.

[3052]

note this style is also documented here

https://wikipedia.org/wiki/Continuation-passing_style