Trying to make the <insert/> element more readable

https://www.w3.org/community/xformsusers/wiki/XForms_2.0#The_insert_Element

The text for the insert element is two pages of fairly opaque text, which I have recently thought about a lot trying to make it more digestible.

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The target-sequence is obtained from the element evaluation context.

• If the target-sequence is empty:
  • if there is no origin attribute, the insert action has no effect
  • if there is an origin attribute:

    The origin-sequence is obtained

    • if the origin-sequence is empty, the insert action has no effectthe insert action has no effect
    • if the origin-sequence is non-empty:

      the nodes of the origin-sequence are added one by one to the context element

• If the target-sequence is non empty:
  • if there is no origin attribute:

    the last element of the target-sequence is copied, and added to the target sequence

  • if there is an origin attribute:

    the origin-sequence is obtained

    • if the origin-sequence is empty, the insert action has no effect
    • if the origin-sequence is non empty:

      the nodes are added one by one to the target sequence.

An origin sequence is obtained by evaluating the origin attribute in the in-scope evaluation context, and removing any root nodes (parents of document elements) from the resulting sequence. An implementation may choose not to include namespace nodes in the origin-sequence, in particular if the namespace axis is not supported or if inserting the namespace node would make the data model inconsistent.

An element is added to a sequence:

• if the sequence has sort properties:

  by inserting the element at the appropriate sort position in the sequence

• if the sequence does not have sort properties:

  by inserting the element according to the at and position values:

  • if the at attribute is present:

    it is evaluated as a number in the Element Evaluation Context and rounded to the nearest integer;
    if the result is not a number, is less than 1 or is greater than the target-sequence size: the insert action has no effect.