Table of contents

Appendices

1.2 Terminology

The terminology used to describe XML documents is defined in the body of this specification. The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when EMPHASIZED, are to be interpreted as described in [rfc2119]. In addition, the terms defined in the following list are used in building those definitions and in describing the actions of an XML processor:

error

A violation of the rules of this specification; results are undefined. Unless otherwise specified, failure to observe a prescription of this specification indicated by one of the keywords MUST, REQUIRED, MUST NOT, SHALL and SHALL NOT is an error. Conforming software MAY detect and report an error and MAY recover from it.

fatal error

An error which a conforming XML Processor MUST detect and report to the application. After encountering a fatal error, the processor MAY continue processing the data to search for further errors and MAY report such errors to the application. In order to support correction of errors, the processor MAY make unprocessed data from the document (with intermingled character data and markup) available to the application. Once a fatal error is detected, however, the processor MUST NOT continue normal processing (i.e., it MUST NOT continue to pass character data and information about the document's logical structure to the application in the normal way).

at user option

Conforming software MAY or MUST (depending on the modal verb in the sentence) behave as described; if it does, it MUST provide users a means to enable or disable the behavior described.

validity constraint

A rule which applies to all Validity XML documents. Violations of validity constraints are errors; they MUST, at user option, be reported by Validating Processor.

well-formedness constraint

A rule which applies to all Well-Formed XML documents. Violations of well-formedness constraints are Fatal Error.

match

(Of strings or names:) Two strings or names being compared MUST be identical. Characters with multiple possible representations in Unicode (e.g. characters with both precomposed and base+diacritic forms) match only if they have the same representation in both strings. No case folding is performed. (Of strings and rules in the grammar:) A string matches a grammatical production if it belongs to the language generated by that production. (Of content and content models:) An element matches its declaration when it conforms in the fashion described in the constraint [Element Valid].

for compatibility

Marks a sentence describing a feature of XML included solely to ensure that XML remains compatible with SGML.

for interoperability

Marks a sentence describing a non-binding recommendation included to increase the chances that XML documents can be processed by the existing installed base of SGML processors which predate the WebSGML Adaptations Annex to ISO 8879.