# `Statifier.Document.Content`
[🔗](https://github.com/riddler/statifier-ex/blob/v2.0.0/lib/statifier/document/content.ex#L1)

A `<content>` element: static text, an `expr`, markup, or (representably,
if not validly) any combination.

Spec 5.6 allows `<content>` children to be "text, XML from any namespace,
or a mixture of both". Preserving non-text markup would mean holding a DOM
subtree inside a Document struct, crossing the layer boundary this rewrite
is organized around - so `markup` holds a verbatim source slice instead
(ADR-0041), not a subtree: no DOM node ever reaches this struct. The slice
is opaque bytes here; the child document it describes is only compiled at
invoke time, from `markup`, through `Statifier.Invoke.Source.resolve/2`.

`markup` is `nil` unless `<content>` has at least one element child; when
present, it is the exact source bytes from the start of the first
non-whitespace child to the end of the last non-whitespace child, elements
and text runs alike, so a 5.6.2 "mixture" slices whole. Unlike `text`
below, this slice does **not** fold line breaks - it keeps its raw CRLFs
and lone CRs exactly as written; the parser's XML 1.0 2.11 fold only
applies when the child document `markup` describes is itself parsed, at
invoke time (ADR-0045 decision item 5). `markup_location`
is that slice's own span in the parent source - its `start_offset` is what
makes a byte offset inside the child document translatable back into a
parent-document offset by plain arithmetic (ADR-0014).

`text` is `Statifier.Parser.DOM.text/1`'s concatenation of the direct text
children, folded per the parser's XML 1.0 2.11 line-break fold
(ADR-0045), and has no span of its own: an entity reference or a CDATA
section can split that concatenation across more than one run in the
source, so there is no single span to give it. This `Content` node's own
`location` is what a diagnostic about the text points at instead.

`expr`, `text`, and `markup` are all nilable and all representable at the
same time, even though spec 5.6 says a document MUST NOT specify both
`expr` and content. That mutual exclusion is a validator concern, not this
layer's - holding all three is exactly what lets
`Statifier.Validator.Checks.Content` report a document that violates it,
as `{:content_expr_and_text, expr}` at this node's own `location`.
Whitespace-only `text` is source formatting rather than a payload and is
not reported.

# `t`

```elixir
@type t() :: %Statifier.Document.Content{
  attribute_locations: Statifier.Document.attribute_locations(),
  expr: String.t() | nil,
  location: Statifier.Parser.Location.t(),
  markup: String.t() | nil,
  markup_location: Statifier.Parser.Location.t() | nil,
  text: String.t() | nil
}
```

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*Consult [api-reference.md](api-reference.md) for complete listing*