reference in content
as a reference anywhere after the start-tag and before the end-tag of an element; corresponds to the nonterminal content.
attribute value
the content of the AttValue (the text between the ' or " delimiters) as the attribute value.
included
An entity is included when its replacement text is retrieved and processed, in place of the reference itself, as though it were part of the document at the location the reference was recognized.
attribute specifications
The Name-AttValue pairs are referred to as the attribute specifications of the element
comments
Comments may appear anywhere in a document outside other markup; in addition, they may appear within the document type declaration at places allowed by the grammar. They are not part of the document's character data; an XML processor may, but need not, make it possible for an application to retrieve the text of comments. For compatibility, the string -- (double-hyphen) must not occur within comments.
XML declaration
XML documents [E107]should begin with an XML declaration which specifies the version of XML being used.
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.
start-tag
The beginning of every non-empty XML element is marked by a start-tag.
parent
As a consequence of this, for each non-root element C in the document, there is one other element P in the document such that C is in the content of P, but is not in the content of any other element that is in the content of P. P is referred to as the parent of C, and C as a child of P.
replacement text
The replacement text is the content of the entity, after replacement of character references and parameter-entity references.
must
Conforming documents and XML processors are required to behave as described; otherwise they are in error.
content
The text between the start-tag and end-tag is called the element's content:
validity constraint
A rule which applies to all valid XML documents. Violations of validity constraints are errors; they must, at user option, be reported by validating XML processors.
empty-element tag
An empty-element tag takes a special form:
conditional sections
Conditional sections are portions of the document type declaration external subset which are included in, or excluded from, the logical structure of the DTD based on the keyword which governs them.
empty
[E97]An element with no content is said to be empty.
markup declaration
A markup declaration is an element type declaration, an attribute-list declaration, an entity declaration, or a notation declaration.
default
If the declaration is neither #REQUIRED nor #IMPLIED, then the AttValue value contains the declared default value; the #FIXED keyword states that the attribute must always have the default value. If a default value is declared, when an XML processor encounters an omitted attribute, it is to behave as though the attribute were present with the declared default value.
character
A character is an atomic unit of text as specified by ISO/IEC 10646 [E67](see also ). Legal characters are tab, carriage return, line feed, and the legal [E35]graphic characters of Unicode and ISO/IEC 10646. [E69]The versions of these standards cited in were current at the time this document was prepared. New characters may be added to these standards by amendments or new editions. Consequently, XML processors must accept any character in the range specified for Char. The use of compatibility characters, as defined in section 6.8 of [E67](see also D21 in section 3.6 of ), is discouraged.
well-formed
A textual object is a well-formed XML document if:
internal entity
If the entity definition is an EntityValue, the defined entity is called an internal entity. There is no separate physical storage object, and the content of the entity is given in the declaration.
system identifier
The SystemLiteral is called the entity's system identifier. It is a [E88]URI reference[E66] (as defined in , updated by ), [E76]meant to be dereferenced to obtain input for the XML processor to construct the entity's replacement text.
valid
An XML document is valid if it has an associated document type declaration and if the document complies with the constraints expressed in it.
root
There is exactly one element, called the root, or document element, no part of which appears in the content of any other element.
for compatibility
[E87]Marks a sentence describing a feature of XML included solely to ensure that XML remains compatible with SGML.
entity reference
An entity reference refers to the content of a named entity.
processing instructions
Processing instructions (PIs) allow documents to contain instructions for applications.
application
It is assumed that an XML processor is doing its work on behalf of another module, called the application.
character reference
A character reference refers to a specific character in the ISO/IEC 10646 character set, for example one not directly accessible from available input devices.
literal entity value
The literal entity value is the quoted string actually present in the entity declaration, corresponding to the non-terminal EntityValue.
attribute-list declarations
Attribute-list declarations specify the name, data type, and default value (if any) of each attribute associated with a given element type:
parsed entity's
A parsed entity's contents are referred to as its replacement text; this text is considered an integral part of the document.
error
A violation of the rules of this specification; results are undefined. Conforming software may detect and report an error and may recover from it.
document entity
The document entity serves as the root of the entity tree and a starting-point for an XML processor.
attribute name
with the Name in each pair referred to as the attribute name
end-tag
The end of every element that begins with a start-tag must be marked by an end-tag containing a name that echoes the element's type as given in the start-tag:
match
(Of strings or names:) Two strings or names being compared must be identical. Characters with multiple possible representations in ISO/IEC 10646 (e.g. characters with both precomposed and base+diacritic forms) match only if they have the same representation in both strings. [E85]At user option, processors may normalize such characters to some canonical form. 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 .
unparsed entity
An unparsed entity is a resource whose contents may or may not be text, and if text, [E25]may be other than XML. Each unparsed entity has an associated notation, identified by name. Beyond a requirement that an XML processor make the identifiers for the entity and notation available to the application, XML places no constraints on the contents of unparsed entities.
document type declaration
The XML document type declaration contains or points to markup declarations that provide a grammar for a class of documents. This grammar is known as a document type definition, or DTD. The document type declaration can point to an external subset (a special kind of external entity) containing markup declarations, or can contain the markup declarations directly in an internal subset, or can do both. The DTD for a document consists of both subsets taken together.
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).
may
Conforming documents and XML processors are permitted to but need not behave as described.
external markup declaration
An external markup declaration is defined as a markup declaration occurring in the external subset or in a parameter entity (external or internal, the latter being included because non-validating processors are not required to read them).
elements
Each XML document contains one or more elements, the boundaries of which are either delimited by start-tags and end-tags, or, for empty elements, by an empty-element tag. Each element has a type, identified by name, sometimes called its generic identifier (GI), and may have a set of attribute specifications.
external entity
If the entity is not internal, it is an external entity, declared as follows:
element type declaration
An element type declaration takes the form:
name
A Name is a token beginning with a letter or one of a few punctuation characters, and continuing with letters, digits, hyphens, underscores, colons, or full stops, together known as name characters.
validating processors
Validating processors must[E21], at user option, report violations of the constraints expressed by the declarations in the DTD, and failures to fulfill the validity constraints given in this specification.
character data
All text that is not markup constitutes the character data of the document.
reference in entity value
as a reference within a parameter or internal entity's literal entity value in the entity's declaration; corresponds to the nonterminal EntityValue.
enumerated attributes
Enumerated attributes can take one of a list of values provided in the declaration
XML processor
A software module called an XML processor is used to read XML documents and provide access to their content and structure.
for interoperability
[E87]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.
text
A parsed entity contains text, a sequence of characters, which may represent markup or character data.
CDATA sections
CDATA sections may occur anywhere character data may occur; they are used to escape blocks of text containing characters which would otherwise be recognized as markup. CDATA sections begin with the string <![CDATA[ and end with the string ]]>:
element content
An element type has element content when elements of that type must contain only child elements (no character data), optionally separated by white space (characters matching the nonterminal S).
general entities
General entities are entities for use within the document content. In this specification, general entities are sometimes referred to with the unqualified term entity when this leads to no ambiguity.
parameter-entity references
Parameter-entity references use percent-sign (%) and semicolon (;) as delimiters.
notations
Notations identify by name the format of unparsed entities, the format of elements which bear a notation attribute, or the application to which a processing instruction is addressed.
process
While they are not required to check the document for validity, they are required to process all the declarations they read in the internal DTD subset and in any parameter entity that they read, up to the first reference to a parameter entity that they do not read; that is to say, they must use the information in those declarations to normalize attribute values, include the replacement text of internal entities, and supply default attribute values.
well-formedness constraint
A rule which applies to all well-formed XML documents. Violations of well-formedness constraints are fatal errors.
occurs as attribute value
as a Name, not a reference, appearing either as the value of an attribute which has been declared as type ENTITY, or as one of the space-separated tokens in the value of an attribute which has been declared as type ENTITIES.
notation declarations
Notation declarations provide a name for the notation, for use in entity and attribute-list declarations and in attribute specifications, and an external identifier for the notation which may allow an XML processor or its client application to locate a helper application capable of processing data in the given notation.
public identifier
In addition to a system identifier, an external identifier may include a public identifier.
XML document
A data object is an XML document if it is well-formed, as defined in this specification. A well-formed XML document may in addition be valid if it meets certain further constraints.
mixed content
An element type has mixed content when elements of that type may contain character data, optionally interspersed with child elements.
escape
Entity and character references can both be used to escape the left angle bracket, ampersand, and other delimiters. A set of general entities (amp, lt, gt, apos, quot) is specified for this purpose. Numeric character references may also be used; they are expanded immediately when recognized and must be treated as character data, so the numeric character references < and & may be used to escape < and & when they occur in character data.
reference in attribute value
as a reference within either the value of an attribute in a start-tag, or a default value in an attribute declaration; corresponds to the nonterminal AttValue.
reference in DTD
[E90]as a reference within either the internal or external subsets of the DTD, but outside of an EntityValue, AttValue, PI, Comment, SystemLiteral, PubidLiteral, or the contents of an ignored conditional section (see )..
markup
Markup takes the form of start-tags, end-tags, empty-element tags, entity references, character references, comments, CDATA section delimiters, document type declarations, processing instructions, [E89]XML declarations, text declarations, and any white space that is at the top level of the document entity (that is, outside the document element and not inside any other markup).
Extensible Markup Language (XML) 1.0
2000-10-06
http://www.w3.org/TR/2000/REC-xml-20001006
Jean
Paoli
Eve
Maler
C. M.
Sperberg-McQueen
Tim
Bray