- absolute path expression
An absolute path expression is an instance of the production AbsolutePathExpr: it consists of either (a) the operator / followed by zero or more operands separated by / or // operators, or (b) the operator // followed by one or more operands separated by / or // operators.
- and expression
An and expression is a non-trivial instance of the production AndExpr.
- anonymous function
An anonymous function is a function item with no name. Anonymous functions may be created, for example, by evaluating an inline function expression or by partial function application.
- application function
Application functions are function definitions written in a host language such as XQuery or XSLT whose syntax and semantics are defined in this family of specifications. Their behavior (including the rules determining the static and dynamic context) follows the rules for such functions in the relevant host language specification.
- argument expression
An argument to a function call is either an argument expression or an ArgumentPlaceholder (?); in both cases it may either be supplied positionally, or identified by a name (called a keyword).
- arity range
A function definition has an arity range, which is a range of consecutive non-negative integers. If the function definition has M required parameters and N optional parameters, then its arity range is from M to M+N inclusive.
- array
An array is a function item that associates a set of positions, represented as positive integer keys, with values.
- associated value
The value associated with a given key is called the associated value of the key.
- atomic item
An atomic item is a value in the value space of an atomic type, as defined in [XML Schema 1.0] or [XML Schema 1.1].
- atomic type
An atomic type is a simple schema type whose {variety}XS11-1 is atomic.
- atomization
Atomization of a sequence is defined as the result of invoking the fn:data function, as defined in [Functions and Operators 4.0] section 12.1.6 fn:data.
- available binary resources
Available binary resources. This is a mapping of strings to binary resources. Each string represents the absolute URI of a resource. The resource is returned by the fn:unparsed-binary function when applied to that URI.
- available documents
Available documents. This is a mapping of strings to document nodes. Each string represents the absolute URI of a resource. The document node is the root of a tree that represents that resource using the data model. The document node is returned by the fn:doc function when applied to that URI.
- available item collections
Available collections. This is a mapping of strings to sequences of items. Each string represents the absolute URI of a resource. The sequence of items represents the result of the fn:collection function when that URI is supplied as the argument.
- available text resources
Available text resources. This is a mapping of strings to text resources. Each string represents the absolute URI of a resource. The resource is returned by the fn:unparsed-text function when applied to that URI.
- available uri collections
Available URI collections. This is a mapping of strings to sequences of URIs. The string represents the absolute URI of a resource which can be interpreted as an aggregation of a number of individual resources each of which has its own URI. The sequence of URIs represents the result of the fn:uri-collection function when that URI is supplied as the argument.
- axis step
An axis step is an instance of the production AxisStep: it is an expression that returns a sequence of GNodes that are reachable from a starting GNode via a specified axis. An axis step has three parts: an axis, which defines the direction of movement for the step, a node test, which selects GNodes based on their properties, and zero or more predicates which are used to filter the results.
- binding collection
The result of evaluating the binding expression in a for expression is called the binding collection
- choice item type
A choice item type defines an item type that is the union of a number of alternatives. For example the type (xs:hexBinary | xs:base64Binary) defines the union of these two primitive atomic types, while the type (map(*) | array(*)) matches any item that is either a map or an array.
- coercion rules
The coercion rules are rules used to convert a supplied value to a required type, for example when converting an argument of a function call to the declared type of the function parameter.
- collation
A collation is a specification of the manner in which strings and URIs are compared and, by extension, ordered. For a more complete definition of collation, see [Functions and Operators 4.0] section 5.3 Comparison of strings.
- comma operator
A comma operator is a comma used specifically as the operator in a sequence expression.
- complex terminal
A complex terminal is a variable terminal whose production rule references, directly or indirectly, an ordinary production rule.
- constructor function
The constructor function for a given simple type is used to convert instances of other simple types into the given type. The semantics of the constructor function call T($arg) are defined to be equivalent to the expression $arg cast as T?.
- content expression
In an enclosed expression, the optional expression enclosed in curly brackets is called the content expression.
- context dependent
A function definition is said to be context dependent if its result depends on the static or dynamic context of its caller. A function definition may be context-dependent for some arities in its arity range, and context-independent for others: for example fn:name#0 is context-dependent while fn:name#1 is context-independent.
- context node
When the context value is a single item, it can also be referred to as the context item; when it is a single node, it can also be referred to as the context node.
- context position
The context position is the position of the context value within the series of values currently being processed.
- context size
The context size is the number of values in the series of values currently being processed.
- context value
The context value is the value currently being processed.
- current dateTime
Current dateTime. This information represents an implementation-dependent point in time during the processing of an expression, and includes an explicit timezone. It can be retrieved by the fn:current-dateTime function. If called multiple times during the execution of an expression, this function always returns the same result.
- data model
XPath 4.0 operates on the abstract, logical structure of an XML document or JSON object rather than its surface syntax. This logical structure, known as the data model, is defined in [XDM 4.0].
- decimal-separator
decimal-separator(M, R) is used to separate the integer part of the number from the fractional part. The default value for both the marker and the rendition is U+002E (FULL STOP, PERIOD, .) .
- default calendar
Default calendar. This is the calendar used when formatting dates in human-readable output (for example, by the functions fn:format-date and fn:format-dateTime) if no other calendar is requested. The value is a string.
- default collation
Default collation. This identifies one of the collations in statically known collations as the collation to be used by functions and operators for comparing and ordering values of type xs:string and xs:anyURI (and types derived from them) when no explicit collation is specified.
- default collection
Default collection. This is the sequence of items that would result from calling the fn:collection function with no arguments.
- default element namespace rule
When an unprefixed lexical QName is expanded using the default element namespace rule, then it uses the default namespace for elements and types. If this is absent, or if it takes the special value ##any, then the no-namespace rule is used.
- default function namespace
Default function namespace. This determines how unprefixed lexical QNames appearing in static function calls or named function references are interpreted.Default function namespace. This determines how unprefixed lexical QNames appearing in a static function call or a named function reference are interpreted.Default function namespace. This determines how unprefixed lexical QNames appearing in static functiona static function call calls or named functionor a named function reference references are interpreted.
- default function namespace rule
When an unprefixed lexical QName is expanded using the default function namespace rule, the processor searches for a matching function definition as follows: first, if the static context includes a no-namespace function definition with the required local name and arity, then that function definition is used; otherwise, the name is expanded using the default function namespace from the static context.
- default in-scope namespace
The default in-scope namespace of an element node
- default language
Default language. This is the natural language used when creating human-readable output (for example, by the functions fn:format-date and fn:format-integer) if no other language is requested. The value is a language code as defined by the type xs:language.
- default namespace for elements and types
Default namespace for elements and types. This is either a namespace URI, or the special value "##any", or absentDM. This indicates how unprefixed QNames are interpreted when they appear in a position where an element name or type name is expected.
- default place
Default place. This is a geographical location used to identify the place where events happened (or will happen) when processing dates and times using functions such as fn:format-date, fn:format-dateTime, and fn:civil-timezone, if no other place is specified. It is used when translating timezone offsets to civil timezone names, and when using calendars where the translation from ISO dates/times to a local representation is dependent on geographical location. Possible representations of this information are an ISO country code or an Olson timezone name, but implementations are free to use other representations from which the above information can be derived. The only requirement is that it should uniquely identify a civil timezone, which means that country codes for countries with multiple timezones, such as the United States, are inadequate.
- default type namespace rule
When an unprefixed lexical QName is expanded using the default type namespace rule, it uses the default namespace for elements and types. If this is absent, the no-namespace rule is used. If the default namespace for elements and types has the special value ##any, then the lexical QName refers to a name in the namespace http://www.w3.org/2001/XMLSchema.
- default URI collection
Default URI collection. This is the sequence of URIs that would result from calling the fn:uri-collection function with no arguments.
- delimiting terminal symbol
The delimiting terminal symbols are: !!=#$()**:+,-->...///::*:::=;<<<<===!>=>=?>>>=>>??[@[]```{{{|||}}}×÷AposStringLiteralBracedURILiteralQuotStringLiteralStringLiteral
- derives from
A schema typeS1 is said to derive fromschema typeS2 if any of the following conditions is true:
- digit
digit(M) is a character used in the picture string to represent an optional digit; the default value is U+0023 (NUMBER SIGN, #) .
- document order
Informally, document order is the order in which nodes appear in the XML serialization of a document.
- dynamically known function definitions
Dynamically known function definitions. This is a set of function definitions. It includes the statically known function definitions as a subset, but may include other function definitions that are not known statically.
- dynamic context
The dynamic context of an expression is defined as information that is needed for the dynamic evaluation of an expression, beyond any information that is needed from the static context.
- dynamic error
A dynamic error is an error that must be detected during the dynamic evaluation phase and may be detected during the static analysis phase.
- dynamic evaluation phase
The dynamic evaluation phase is the phase during which the value of an expression is computed.
- dynamic function call
is
- dynamic type
Every value matches one or more sequence types. A value is said to have a dynamic typeT if it matches (or is an instance of) the sequence type T.
- effective boolean value
The effective boolean value of a value is defined as the result of applying the fn:boolean function to the value.
- element name matching rule
When an unprefixed lexical QName is expanded using the element name matching rule rule, then it uses the default namespace for elements and types. If this is absent, then it uses the no-namespace rule. But if it takes the special value ##any, then the name is taken as matching any expanded QName with the corresponding local part, regardless of namespace: that is, the unprefixed name local is interpreted as *:local.
- empty sequence
A sequence containing zero items is called an empty sequence.
- enclosed expression
An enclosed expression is an instance of the EnclosedExpr production, which allows an optional expression within curly brackets.
- entry
Each key / value pair in a map is called an entry.
- enumeration type
An EnumerationType accepts a fixed set of string values.
- environment variables
Environment variables. This is a mapping from names to values. Both the names and the values are strings. The names are compared using an implementation-defined collation, and are unique under this collation. The set of environment variables is implementation-defined and may be empty.
- error value
In addition to its identifying QName, a dynamic error may also carry a descriptive string and one or more additional values called error values.
- Executable Base URI
Executable Base URI. This is an absolute URI used to resolve relative URIs during the evaluation of expressions; it is used, for example, to resolve a relative URI supplied to the fn:doc or fn:unparsed-text functions.
- expanded QName
An expanded QName is a triple: its components are a prefix, a local name, and a namespace URI. In the case of a name in no namespace, the namespace URI and prefix are both absent. In the case of a name in the default namespace, the prefix is absent.
- exponent-separator
exponent-separator(M, R) is used to separate the mantissa from the exponent in scientific notation. The default value for both the marker and the rendition is U+0065 (LATIN SMALL LETTER E, e) .
- expression context
The expression context for a given expression consists of all the information that can affect the result of the expression.
- external function
External functions can be characterized as functions that are neither part of the processor implementation, nor written in a language whose semantics are under the control of this family of specifications. The semantics of external functions, including any context dependencies, are entirely implementation-defined. In XSLT, external functions are called 24.1 Extension Functions XT30.
- filter expression
A filter expression is an instance of the construct FilterExpr: that is, it is an expression in the form E1[E2]. Its effect is to return those items from the value of E1 that satisfy the predicate in E2.
- filter expression for maps and arrays
A filter expression for maps and arrays is an instance of the construct FilterExprAM: that is, it is an expression in the form E1?[E2]. Its effect is to evaluate E1 to return an array or map, and to select members of the array, or entries from the map, that satisfy the predicate in E2.
- fixed focus
A fixed focus is a focus for an expression that is evaluated once, rather than being applied to a series of values; in a fixed focus, the context value is set to one specific value, the context position is 1, and the context size is 1.
- focus
The first three components of the dynamic context (context value, context position, and context size) are called the focus of the expression.
- focus function
A focus function is an inline function expression in which the function signature is implicit: the function takes a single argument of type item()* (that is, any value), and binds this to the context value when evaluating the function body, which returns a result of type item()*.
- function coercion
Function coercion wraps a function item in a new function whose signature is the same as the expected type. This effectively delays the checking of the argument and return types until the function is called.
- function definition
A function definition contains information used to evaluate a static function call, including the name, parameters, and return type of the function.
- function item
A function item is an item that can be called using a dynamic function call.
- generalized atomic type
A generalized atomic type is an item type whose instances are all atomic items. Generalized atomic types include (a) atomic types, either built-in (for example xs:integer) or imported from a schema, (b) pure union types, either built-in (xs:numeric and xs:error) or imported from a schema, (c) choice item types if their alternatives are all generalized atomic types, and (d) enumeration types.
- GNode
The term generic node or GNode is a collective term for XNodes (more commonly called simply nodes) representing the parts of an XML document, and JNodes, often used to represent the parts of a JSON document.
- grouping-separator
grouping-separator(M, R) is used to separate groups of digits (for example as a thousands separator). The default value for both the marker and the rendition is U+002C (COMMA, ,) .
- GTree
The term GTree means JTree or XTree.
- guarded
An expression E is said to be guarded by some governing condition C if evaluation of E is not allowed to fail with a dynamic error except when C applies.
- host language
A host language for XPath is any environment that provides capabilities for XPath expressions to be defined and evaluated, and that supplies a static and dynamic context for their evaluation.
- ignorable whitespace
Ignorable whitespace consists of any whitespace characters that may occur between terminals, unless these characters occur in the context of a production marked with a ws:explicit annotation, in which case they can occur only where explicitly specified (see A.3.4.2 Explicit Whitespace Handling).
- implausible
Certain expressions, while not erroneous, are classified as being implausible, because they achieve no useful effect.
- implementation defined
Implementation-defined indicates an aspect that may differ between implementations, but must be specified by the implementer for each particular implementation.
- implementation dependent
Implementation-dependent indicates an aspect that may differ between implementations, is not specified by this or any W3C specification, and is not required to be specified by the implementer for any particular implementation.
- implicit timezone
Implicit timezone. This is the timezone to be used when a date, time, or dateTime value that does not have a timezone is used in a comparison or arithmetic operation. The implicit timezone is an implementation-defined value of type xs:dayTimeDuration. See 3.2.7.3 Timezones XS1-2 or 3.3.7 dateTime XS11-2 for the range of valid values of a timezone.
- infinity
infinity(R) is the string used to represent the double value infinity (INF); the default value is the string "Infinity"
- inline function expression
An inline function expression is an instance of the construct InlineFunctionExpr. When evaluated, an inline function expression creates an anonymous function whose properties are defined directly in the inline function expression.
- in-scope attribute declarations
In-scope attribute declarations. Each attribute declaration is identified either by an expanded QName (for a top-level attribute declaration) or by an implementation-dependent attribute identifier (for a local attribute declaration).
- in-scope element declarations
In-scope element declarations. Each element declaration is identified either by an expanded QName (for a top-level element declaration) or by an implementation-dependent element identifier (for a local element declaration).
- in-scope named item types
In-scope named item types. This is a mapping from expanded QNames to named item types.
- in-scope namespaces
The in-scope namespaces property of an element node is a set of namespace bindings, each of which associates a namespace prefix with a URI.
- in-scope schema definitions
In-scope schema definitions is a generic term for all the element declarations, attribute declarations, and schema type definitions that are in scope during static analysis of an expression.
- in-scope schema type
In-scope schema types. Each schema type definition is identified either by an expanded QName (for a named type) or by an implementation-dependent type identifier (for an anonymous type). The in-scope schema types include the predefined schema types described in 3.5 Schema Types.
- in-scope variables
In-scope variables. This is a mapping from expanded QNames to sequence types. It defines the set of variables that are available for reference within an expression. The expanded QName is the name of the variable, and the type is the static type of the variable.
- item
An item is either an atomic item, a node, or a function item.
- item type
An item type is a type that can be expressed using the ItemType syntax, which forms part of the SequenceType syntax. Item types match individual items.
- item type designator
An item type designator is a syntactic construct conforming to the grammar rule ItemType. An item type designator is said to designate an item type.
- JNode
A JNode is a kind of item used to represent a value within the context of a tree of maps and arrays. A root JNode represents a map or array; a non-root JNode represents a member of an array or an entry in a map.
- JTree
A tree that is rooted at a parentless JNode is referred to as a JTree.
- kind test
An alternative form of a node test called a type test can select XNodes based on their type, or in the case of JNodes, the type of their contained ·content·
- lexical QName
A lexical QName is a name that conforms to the syntax of the QName production
- literal
A literal is a direct syntactic representation of an atomic item.
- literal terminal
A literal terminal is a token appearing as a string in quotation marks on the right-hand side of an ordinary production rule.
- logical expression
A logical expression is either an and expression or an or expression. If a logical expression does not raise an error, its value is always one of the boolean values true or false.
- lookup expression
A lookup expression is an instance of the production LookupExpr: that is, an expression in the form E1?KS, where E1 is an expression returning a sequence of maps or arrays, and KS is a key specifier, which indicates which entries in a map, or members in an array, should be selected.
- map
A map is a function that associates a set of keys with values, resulting in a collection of key / value pairs.
- mapping arrow operator
The mapping arrow operator=!> applies a function to each item in a sequence.
- may
MAY means that an item is truly optional.
- member
The values of an array are called its members.
- minus-sign
minus-sign(R) is the string used to mark negative numbers; the default value is U+002D (HYPHEN-MINUS, -) .
- must
MUST means that the item is an absolute requirement of the specification.
- must not
MUST NOT means that the item is an absolute prohibition of the specification.
- named function reference
A named function reference is an instance of the production NamedFunctionRef: it is an expression (written name#arity) which evaluates to a function item, the details of the function item being based on the properties of a function definition in the static context.
- named item type
A named item type is an ItemType identified by an expanded QName.
- namespace binding
A namespace binding is a pair comprising a namespace prefix (which is either an xs:NCName or empty), and a namespace URI.
- namespace-sensitive
The namespace-sensitive types are xs:QName, xs:NOTATION, types derived by restriction from xs:QName or xs:NOTATION, list types that have a namespace-sensitive item type, and union types with a namespace-sensitive type in their transitive membership.
- name test
A node test that consists only of an EQName or a Wildcard is called a name test.
- NaN
NaN(R) is the string used to represent the double value NaN (not a number); the default value is the string "NaN"
- node
Except where the context indicates otherwise, the term node is used as a synonym for XNode.
- node test
A node test is a condition on the properties of a GNode. A node test determines which GNodes returned by an axis are selected by a step.
- no-namespace rule
When an unprefixed lexical QName is expanded using the no-namespace rule, it is interpreted as having an absent namespace URI.
- non-delimiting terminal symbol
The non-delimiting terminal symbols are: ancestorancestor-or-selfandarrayasatattributecastcastablechildcommentdeclaredefaultdescendantdescendant-or-selfdivdocument-nodeelementelseempty-sequenceenumeqeveryexceptfnfollowingfollowing-or-selffollowing-siblingfollowing-sibling-or-selffollowsfollows-or-isforfunctiongegetgnodegtidivifininstanceintersectisis-notitemjnodekeyleletltmapmembermodnamespacenamespace-nodenenodeoforotherwiseparentprecedesprecedes-or-isprecedingpreceding-or-selfpreceding-siblingpreceding-sibling-or-selfprocessing-instructionrecordreturnsatisfiesschema-attributeschema-elementselfsometextthentotreattypeunionvalueBinaryIntegerLiteralDecimalLiteralDoubleLiteralHexIntegerLiteralIntegerLiteralNCNameQNameURIQualifiedName
- non-trivial
A construct is said to be a non-trivial instance of a grammatical production if it is not also an instance of one of its sub-productions.
- numeric
The type xs:numeric is defined as a union type with member types xs:double, xs:float, and xs:decimal. An item that is an instance of any of these types is referred to as a numeric value, and a type that is a subtype of xs:numeric is referred to as a numeric type.
- ordinary production rule
An ordinary production rule is a production rule in A.1 EBNF that is not annotated ws:explicit.
- or expression
An or expression is a non-trivial instance of the production OrExpr.
- partial function application
A static or dynamic function call is a partial function application if one or more arguments is an ArgumentPlaceholder.
- partially applied function
A partially applied function is a function created by partial function application.
- path expression
A path expression is either an absolute path expression or a relative path expression
- pattern-separator
pattern-separator(M) is a character used to separate positive and negative sub-pictures in a picture string; the default value is U+003B (SEMICOLON, ;) .
- percent
percent(M, R) is used to indicate that the number is written as a per-hundred fraction; the default value for both the marker and the rendition is U+0025 (PERCENT SIGN, %) .
- per-mille
per-mille(M, R) is used to indicate that the number is written as a per-thousand fraction; the default value for both the marker and the rendition is U+2030 (PER MILLE SIGN, ‰) .
- pipeline operator
The pipeline operator-> evaluates an expression and binds the result to the context value before evaluating another expression.
- predicate truth value
The predicate truth value of a value $V is the result of the expression if ($V instance of xs:numeric+) then ($V = position()) else fn:boolean($V).
- primary expression
A primary expression is an instance of the production PrimaryExpr. Primary expressions are the basic primitives of the language. They include literals, variable references, context value references, and function calls. A primary expression may also be created by enclosing any expression in parentheses, which is sometimes helpful in controlling the precedence of operators.
- principal node kind
Every axis has a principal node kind. If an axis can contain elements, then the principal node kind is element; otherwise, it is the kind of nodes that the axis can contain.
- pure union type
A pure union type is a simple type that satisfies the following constraints: (a) {variety}XS11-1 is union, (b) the {facets}XS11-1 property is empty, (c) no type in the transitive membership of the union type has {variety}XS11-1list, and (d) no type in the transitive membership of the union type is a type with {variety}XS11-1union having a non-empty {facets}XS11-1 property
- range expression
A range expression is a non-trivial instance of the production RangeExpr. A range expression is used to construct a sequence of integers.
- relative path expression
A relative path expression is a non-trivial instance of the production RelativePathExpr: it consists of two or more operand expressions separated by / or // operators.
- resolve
To resolve a relative URI$rel against a base URI $base is to expand it to an absolute URI, as if by calling the function fn:resolve-uri($rel, $base).
- reverse document order
The node ordering that is the reverse of document order is called reverse document order.
- same key
Two atomic items K1 and K2 have the same key value if fn:atomic-equal(K1, K2) returns true, as specified in [Functions and Operators 4.0] section 2.2.1 fn:atomic-equal
- schema type
A schema type is a complex type or simple type as defined in the [XML Schema 1.0] or [XML Schema 1.1] specifications, including built-in types as well as user-defined types.
- sequence
A sequence is an ordered collection of zero or more items.
- sequence arrow operator
The sequence arrow operator=> applies a function to a supplied sequence.
- sequence concatenation
The sequence concatenation of a number of sequences S1, S2, ... Sn is defined to be the sequence formed from the items of S1, followed by the items from S2, and so on, retaining order.
- sequence expression
A sequence expression is a non-trivial instance of the production rule Expr, that is, an expression containing two or more instances of the production ExprSingle separated by the comma operator.
- sequence type
A sequence type is a type that can be expressed using the SequenceType syntax. Sequence types are used whenever it is necessary to refer to a type in an XPath 4.0 expression. Since all values are sequences, every value matches one or more sequence types.
- sequence type designator
A sequence type designator is a syntactic construct conforming to the grammar rule SequenceType. A sequence type designator is said to designate a sequence type.
- SequenceType matching
SequenceType matching compares a value with an expected sequence type.
- serialization
Serialization is the process of converting an XDM instance to a sequence of octets (step DM4 in Figure 1.), as described in [Serialization 4.0].
- singleton
A sequence containing exactly one item is called a singleton.
- singleton enumeration type
An enumeration type with a single enumerated value E (such as enum("red")) matches an item S if and only if (a) S is an instance of xs:string, and (b) S is equal to E when compared using Unicode codepoint collation. This is referred to as a singleton enumeration type.
- singleton focus
A singleton focus is a fixed focus in which the context value is a singleton item.
- stable
Document order is stable, which means that the relative order of two nodes will not change during the processing of a given expression, even if this order is implementation-dependent.
- statically known collations
Statically known collations. This is an implementation-defined mapping from URI to collation. It defines the names of the collations that are available for use in processing expressions.
- statically known decimal formats
Statically known decimal formats. This is a mapping from QNames to decimal formats, with one default format that has no visible name, referred to as the unnamed decimal format. Each format is available for use when formatting numbers using the fn:format-number function.
- statically known function definitions
Statically known function definitions. This is a set of function definitions.
- statically known namespaces
Statically known namespaces. This is a mapping from prefix to namespace URI that defines all the namespaces that are known during static processing of a given expression.
- static analysis phase
The static analysis phase depends on the expression itself and on the static context. The static analysis phase does not depend on input data (other than schemas).
- Static Base URI
Static Base URI. This is an absolute URI, used to resolve relative URIs during static analysis.
- static context
The static context of an expression is the information that is available during static analysis of the expression, prior to its evaluation.
- static error
An error that can be detected during the static analysis phase, and is not a type error, is a static error.
- static function call
A static function call is an instance of the production FunctionCall: it consists of an EQName followed by a parenthesized list of zero or more arguments.
- static type
The static type of an expression is the best inference that the processor is able to make statically about the type of the result of the expression.
- step
The operands of a path expression are conventionally referred to as steps.
- string value
The string value of a node is a string and can be extracted by applying the string function to the node.
- substantively disjoint
Two sequence types are deemed to be substantively disjoint if (a) neither is a subtype of the other (see 3.3.1 Subtypes of Sequence Types) and (b) the only values that are instances of both types are one or more of the following:
- substitution group
Substitution groups are defined in 2.2.2.2 Element Substitution Group XS1-1 and 2.2.2.2 Element Substitution Group XS11-1. Informally, the substitution group headed by a given element (called the head element) consists of the set of elements that can be substituted for the head element without affecting the outcome of schema validation.
- subtype
Given two sequence types or item types, the rules in this section determine if one is a subtype of the other. If a type A is a subtype of type B, it follows that every value matched by A is also matched by B.
- subtype substitution
The use of a value that has a dynamic type that is a subtype of the expected type is known as subtype substitution.
- symbol
Each rule in the grammar defines one symbol, using the following format:
- symbol separators
Whitespace and Comments function as symbol separators. For the most part, they are not mentioned in the grammar, and may occur between any two terminal symbols mentioned in the grammar, except where that is forbidden by the /* ws: explicit */ annotation in the EBNF, or by the /* xgc: xml-version */ annotation.
- system function
System functions include the functions defined in [Functions and Operators 4.0], functions defined by the specifications of a host language, constructor functions for atomic types, and any additional functions provided by the implementation. System functions are sometimes called built-in functions.
- terminal
A terminal is a symbol or string or pattern that can appear in the right-hand side of a rule, but never appears on the left-hand side in the main grammar, although it may appear on the left-hand side of a rule in the grammar for terminals.
- type annotation
Each element node and attribute node in an XDM instance has a type annotation (described in [XDM 4.0] section 4.1 Schema Information). The type annotation of a node is a reference to a schema type.
- typed value
The typed value of a node is a sequence of atomic items and can be extracted by applying the data function to the node.
- type error
A type error may be raised during the static analysis phase or the dynamic evaluation phase. During the static analysis phase, a type error occurs when the static type of an expression does not match the expected type of the context in which the expression occurs. During the dynamic evaluation phase, a type error occurs when the dynamic type of a value does not match the expected type of the context in which the value occurs.
- URI
Within this specification, the term URI refers to a Universal Resource Identifier as defined in [RFC3986] and extended in [RFC3987] with the new name IRI.
- value
In the data model, a value is always a sequence.
- variable reference
A variable reference is an EQName preceded by a $-sign.
- variable terminal
A variable terminal is an instance of a production rule that is not itself an ordinary production rule but that is named (directly) on the right-hand side of an ordinary production rule.
- variable values
Variable values. This is a mapping from expanded QNames to values. It contains the same expanded QNames as the in-scope variables in the static context for the expression. The expanded QName is the name of the variable and the value is the dynamic value of the variable, which includes its dynamic type.
- warning
In addition to static errors, dynamic errors, and type errors, an XPath 4.0 implementation may raise warnings, either during the static analysis phase or the dynamic evaluation phase. The circumstances in which warnings are raised, and the ways in which warnings are handled, are implementation-defined.
- whitespace
A whitespace character is any of the characters defined by [http://www.w3.org/TR/REC-xml/#NT-S].
- wildcard-matches
In these rules, if MU and NU are NameTestUnions, then MUwildcard-matchesNU is true if every name that matches MU also matches NU.
- XDM instance
The term XDM instance is used, synonymously with the term value, to denote an unconstrained sequence of items.
- XNode
An XNode is an instance of one of the node kinds defined in [XDM 4.0] section 7.1 XML Nodes.
- XPath 1.0 compatibility mode
XPath 1.0 compatibility mode.This value is true if rules for backward compatibility with XPath Version 1.0 are in effect; otherwise it is false.
- xs:anyAtomicType
xs:anyAtomicType is an atomic type that includes all atomic items (and no values that are not atomic). Its base type is xs:anySimpleType from which all simple types, including atomic, list, and union types, are derived. All primitive atomic types, such as xs:decimal and xs:string, have xs:anyAtomicType as their base type.
- xs:dayTimeDuration
xs:dayTimeDuration is derived by restriction from xs:duration. The lexical representation of xs:dayTimeDuration is restricted to contain only day, hour, minute, and second components.
- xs:error
xs:error is a simple type with no value space. It is defined in 3.16.7.3 xs:error XS11-1 and can be used in the 3.1 Sequence Types to raise errors.
- xs:untyped
xs:untyped is used as the type annotation of an element node that has not been validated, or has been validated in skip mode.
- xs:untypedAtomic
xs:untypedAtomic is an atomic type that is used to denote untyped atomic data, such as text that has not been assigned a more specific type.
- xs:yearMonthDuration
xs:yearMonthDuration is derived by restriction from xs:duration. The lexical representation of xs:yearMonthDuration is restricted to contain only year and month components.
- XTree
A tree that is rooted at a parentless XNode is referred to as an XTree.
- zero-digit
zero-digit(M) is the character used in the picture string to represent the digit zero; the default value is U+0030 (DIGIT ZERO, 0) . This character must be a digit (category Nd in the Unicode property database), and it must have the numeric value zero. This property implicitly defines the ten Unicode characters that are used to represent the values 0 to 9 in the function output: Unicode is organized so that each set of decimal digits forms a contiguous block of characters in numerical sequence. Within the picture string any of these ten character can be used (interchangeably) as a place-holder for a mandatory digit. Within the final result string, these ten characters are used to represent the digits zero to nine.