XML support#

ProRock reads and writes XML through classes generated from XSD and WSDL. These real-world schema sets generate units that compile, and documents read and write back with them:

FHIR R4 (HL7) - all resources, a Bundle of 1,000 Patients read in 0.1 s (Large documents)
Office Open XML - SpreadsheetML and DrawingML (main, chart, picture, spreadsheet drawing), the package's core and extended properties (sample) on Dublin Core
SOAP 1.1 and 1.2, WSDL 1.1, WS-Security, ebMS 3.0 messaging headers, the EU VIES VAT service (samples)

This page lists what of XML and XML Schema works, what works in part, and what is not covered yet. ProRock reads and writes documents; it does not validate them against their schema.

The document#

	Status	Notes
Elements, attributes, text	supported
Namespaces and prefixes	supported	any prefixes on read; the document's declarations are written back, its elements with each namespace's own prefix, which can differ from the document's
Character and entity references	supported	`&`, `<`, `A`, `B`
CDATA sections	supported	read as text as it is, written escaped (`a<b`)
Comments, processing instructions, DOCTYPE	supported	skipped on read, not written back
Entities declared in a DTD	not supported	`&name;` stays text - which also rules out entity-expansion attacks
`xml:space="preserve"`	supported	written for text with leading or trailing spaces
Attributes the schema does not know	supported	kept and written back
Elements the schema does not know	supported	kept as their exact text and written back where they were - Office's own extensions (`extLst`, `mc:AlternateContent`) survive a round trip (Xmlite)
Malformed XML	supported	the read fails: `FromXml` returns `False` - tags not closed or crossed, an undeclared prefix in kept content
Mixed content	supported	text runs and child elements in document order (`XmlContent`, `InnerText`) - a FHIR narrative round-trips; text-only mixed content is plain text (`XmlValue`) (Xmlite)

Structures#

	Status	Notes
Sequences, element order	supported	written in the schema's order
Choices	supported	members created on first access; `Chosen` tells which is there (Large documents)
`xs:all`	supported
Repeating elements	supported	typed lists - of objects, or of plain values: `Authors.Author.Add('Ann')`
A repeating choice in mixed order	supported	`<a/><b/><a/>`: each member in its own list, their order across members in `XmlContent` (`[TOrdered]`)
Groups, attribute groups, references	supported	a reference to an element of a simple type is a plain value
Anonymous (inline) types	supported
Presence: absent vs. default	supported	`Present`, `SetPresent`, `Clear` (Xmlite)
`xs:any`	supported	elements of namespaces with generated units are read as objects; others are kept as text
`xs:anyAttribute`	partial	such attributes are kept as attributes the schema does not know, not typed
`elementFormDefault="unqualified"`	partial	read correctly; on write, local elements get the parent's default namespace

Types#

	Status	Notes
Built-in simple types	supported	strings, integers, decimals, booleans, dates as text (Xmlite)
Enumerations	supported	Delphi enums; the exact texts are kept (`true` and `True` are two values)
Restrictions	partial	the base type is used; facets (patterns, lengths, ranges) are not checked
Lists (`xs:list`)	partial	`"1 2 3"` is read and written as the text it is, a string
Unions	partial	the text as written, unless the union has one named member type
Defaults	supported	default values, written only when present or required
`xsi:nil`	not yet	a nil element reads as its default and is written with a value
Exact decimals	partial	`xs:decimal` is a `Double`: up to 15 significant digits come back as the same number, beyond about 17 they are lost (notes)
Text with attributes (simpleContent)	supported	the text in `XmlValue`, the attributes as properties
Complex types by extension or restriction	supported	an extension is a Delphi descendant; a restriction a class of its own

Polymorphism#

	Status	Notes
Derived types with `xsi:type`	partial	written with `SetXsiType`; on read the attribute is kept and written back, but the object stays the declared class - members only the derived type has are not read
Substitution groups	partial	a member gets its head's type; a property of the head's type does not hold members yet

Schema sets#

	Status	Notes
Imports (other namespaces)	supported	one unit per namespace, units use each other
Includes (the same namespace)	supported	several files, one unit
Schemas without `targetNamespace`	not yet	including "chameleon" includes
`xs:redefine`	not supported	reported by the generator
WSDL 1.1, SOAP document/literal	supported	rpc/encoded operations are skipped (listed in the generated unit's header)

What is planned next is on the roadmap. A schema that does not generate or read right is worth an issue: coverage grows through real-world schemas.