Node

A parentless XML element.

Nodes can be shared or inserted into different trees. Serialization derives namespace declarations from each node rather than from parent pointers.

Implements: std.Index[{...Str: Str, ...Int: Node | Str, ...Range[Int]: Array[Node | Str]}], std.Assign[Str, Str]

Constructor

`Node tag *items …`

Creates an element, optionally with attributes and children.

Children are not checked here, matching children.push; verify and serialization reject children other than Node and Str. attrs: is applied before positional Attr values.

Parameters

Name	Type	Description
`tag`	`Str`	Local element name.
`:namespace?`	`Str`	Namespace URI.
`:prefix?`	`Str`	Preferred namespace prefix.
`:attrs?`	`Dict[Sym \| Str, Str]`	Unnamespaced attributes with `Sym` or `Str` keys and `Str` values.
`*items`	`(Attr \| Value)`	Attributes or children.

Errors

TypeError if attrs: is not a dict or one of its values is not a Str.

Example

let item = Node "item" namespace: "urn:inventory" prefix: "inv"
let disk = Node disk
  attrs:
    type: file
    device: disk
  - $ Node driver attrs: {name: "qemu", type: "qcow2"}

Fields

attrs @ std.MutSeq[Attr]

Mutable array-like view of Attr objects in document order.

The view supports indexed assignment and array mutation methods. Duplicate expanded names can exist temporarily, but verification rejects them.

children @ std.MutSeq[Node | Str]

Mutable array-like view of child Node and Str values in document order.

Iterating a node iterates this view directly.

namespace

Mutable namespace URI, or nil for no namespace.

namespaces

Mutable dict containing the complete effective namespace snapshot.

Keys are prefix strings; "" is the default namespace. Parsed descendants retain inherited bindings so they can be detached and serialized.

prefix

Mutable preferred prefix, or nil.

qname

Read-only qualified name formed from prefix and tag.

tag

Mutable local element name.

Methods

`(assign) key value`

Sets an unnamespaced attribute, adding it if it is missing.

Parameters

Name	Type	Description
`key`	`Str`
`value`	`Str`

`(index) key`

Reads an unnamespaced attribute by string or a child by integer index.

Negative integer indexes count from the end.

`(iter)()`

Iterates the children.

`attr[D = nil] name … -> (Str | D)`

Gets the first attribute matching an expanded name.

Parameters

Name	Type	Description
`name`	`Str`	Local attribute name.
`:namespace?`	`Str`	Namespace URI.
`:default?`	`D`	Value returned when absent.
`:else?`	`(() -> D)`	Function evaluated when absent.

Example

let id = node.attr "id" namespace: "urn:inventory"

`delete_attr name … -> Bool`

Deletes all attributes matching an expanded name.

Parameters

Name	Type	Description
`name`	`Str`	Local attribute name.
`:namespace?`	`Str`	Namespace URI.

Returns

Whether an attribute was deleted.

`push child`

Appends a child.

Parameters

Name	Type	Description
`child`	`(Node \| Str)`	Child value.

`set_attr name value …`

Updates the first matching attribute or appends one.

An omitted prefix: mutates the existing value. An explicit prefix, including nil, replaces the attribute because identity fields are immutable.

Parameters

Name	Type	Description
`name`	`Str`	Local attribute name.
`value`	`Str`	Attribute value.
`:namespace?`	`Str`	Namespace URI.
`:prefix?`	`Str`	Preferred namespace prefix.

`traverse() -> Iter[Node | Str]`

Returns a depth-first, parent-first iterator over this node and descendants.