A sequence comparator is an expression that evaluates two sequences of items and results in a true or false value.
- absent
A component of the context that has no value is said to be absent.
- accumulator
An accumulator defines a series of values associated with the nodes of the tree. If an accumulator is applicable to a particular tree, then for each node in the tree, other than attribute and namespace nodes, there will be two values available, called the pre-descent and post-descent values. These two values are available via a pair of functions, accumulator-before and accumulator-after.
- accumulator function
The functions accumulator-before and accumulator-after are referred to as the accumulator functions.
- alias
A stylesheet can use the xsl:namespace-alias element to declare that a literal namespace URI is being used as an alias for a target namespace URI.
- applicable
A template rule is applicable to one or more modes. The modes to which it is applicable are defined by the mode attribute of the xsl:template element. If the attribute is omitted, then the template rule is applicable to the default mode specified in the [xsl:]default-mode attribute of the innermost containing element that has such an attribute, which in turn defaults to the unnamed mode. If the mode attribute is present, then its value must be a non-empty whitespace-separated list of tokens, each of which defines a mode to which the template rule is applicable.
- applicable static namespaces
The applicable static namespaces for an element in a stylesheet module are the fixed namespace bindings for the module if the root element of the module has a fixed-namespaces attribute, or the native namespace bindings of the element otherwise.
- arity range
A function definition has an arity range, which defines the minimum and maximum number of arguments that must be supplied in a call to the function. The static context can contain multiple function definitions with the same name, provided that their arity ranges do not overlap.
- atomize
The term atomization is defined in [XPath 4.0] section 2.6.3 Atomization. It is a process that takes as input a sequence of items, and returns a sequence of atomic items, in which the nodes are replaced by their typed values as defined in [XDM 4.0]. Arrays (see 22 Arrays) are atomized by atomizing their members, recursively.
- attribute set
An attribute set is defined as a set of xsl:attribute-set declarations in the same package that share the same expanded QName.
- attribute set invocation
An attribute set invocation is a pseudo-instruction corresponding to a single EQName appearing within an [xsl:]use-attribute-sets attribute; the effect of the pseudo-instruction is to cause the referenced attribute set to be evaluated.
- attribute value template
In an attribute that is designated as an attribute value template, such as an attribute of a literal result element, an expression can be used by surrounding the expression with curly brackets ({}), following the general rules for value templates
- backwards compatible behavior
An element is processed with backwards compatible behavior if its effective version is less than 4.0.
- base output URI
The base output URI is a URI to be used as the base URI when resolving a relative URI reference allocated to a final result tree. If the transformation generates more than one final result tree, then typically each one will be allocated a URI relative to this base URI.
- basic XSLT processor
A basic XSLT processor is an XSLT processor that implements all the mandatory requirements of this specification with the exception of constructs explicitly associated with an optional feature.
- character map
A character map allows a specific character appearing in a text or attribute node in the final result tree to be substituted by a specified string of characters during serialization.
- circularity
A circularity is said to exist if a construct such as a global variable, an attribute set, or a key, cannot be evaluated without reference to its own value. For example, if the expression or sequence constructor specifying the value of a global variableX references a global variable Y, then the value for Ymust be computed before the value of X. A circularity exists if it is impossible to do this for all global variable definitions.
- coercion rules
The term coercion rules means the coercion rules defined in [XPath 4.0], applied unless otherwise specified with XPath 1.0 compatibility mode set to false.
- collation
Facilities in XSLT 3.0 and XPath 3.0 that require strings to be ordered rely on the concept of a named collation. A collation is a set of rules that determine whether two strings are equal, and if not, which of them is to be sorted before the other.
- combined merge key value
The ordered collection of merge key values computed for one item in a merge input sequence (one for each merge key component within the merge key specification) is referred to as a combined merge key value.
- compatible
The signatures of two components are compatible if they present the same interface to the user of the component. The additional rules depend on the kind of component.
- component
The term component is used to refer to any of the following: a stylesheet function, a named template, a mode, an accumulator, an attribute set, a key, global variable, or a mode.
- containing package
A component declaration results in multiple components, one in the package in which the declaration appears, and potentially one in each package that uses the declaring package, directly or indirectly, subject to the visibility of the component. Each of these multiple components has the same declaring package, but each has a different containing package. For the original component, the declaring package and the containing package are the same; for a copy of a component made as a result of an xsl:use-package declaration, the declaring package will be the original package, and the containing package will be the package in which the xsl:use-package declaration appears.
- context item
The context item is the item currently being processed. An item (see [XDM 4.0]) is either an atomic item (such as an integer, date, or string), a node, or a function item. It changes whenever instructions such as xsl:apply-templates and xsl:for-each are used to process a sequence of items; each item in such a sequence becomes the context item while that item is being processed.
- context node
If the context item is a node (as distinct from an atomic item such as an integer), then it is also referred to as the context node. The context node is not an independent variable, it changes whenever the context item changes. When the context item is an atomic item or a function item, there is no context node.
- context position
The context position is the position of the context item within the sequence of items currently being processed. It changes whenever the context item changes. When an instruction such as xsl:apply-templates or xsl:for-each is used to process a sequence of items, the first item in the sequence is processed with a context position of 1, the second item with a context position of 2, and so on.
- context size
The context size is the number of items in the sequence of items currently being processed. It changes whenever instructions such as xsl:apply-templates and xsl:for-each are used to process a sequence of items; during the processing of each one of those items, the context size is set to the count of the number of items in the sequence (or equivalently, the position of the last item in the sequence).
- current captured groups
While the xsl:matching-substring instruction is active, a set of current captured groups is available, corresponding to the capturing subexpressions of the regular expression.
- current group
The current group is the group itself, as a sequence of items
- current grouping key
The current grouping key is a single atomic item, or in the case of a composite key, a sequence of atomic items, containing the grouping key of the items in the current group.
- current merge group
The current merge group is a map. During evaluation of an xsl:merge instruction, as each group of items with equal combined merge key values is processed, the current merge group is set to a map whose keys are the names of the various merge sources, and whose associated values are the items from each merge source having the relevant composite merge key value.
- current merge key
The current merge key is a an array, whose members are sequences of atomic items. There is one member in the array for each xsl:merge-key element in the merge key specification. During evaluation of an xsl:merge instruction, as each group of items with equal combined merge key values is processed, the current merge key is set to the combined merge key value that these items have in common.
- current mode
At any point in the processing of a stylesheet, there is a current mode. When the transformation is initiated, the current mode is the initial mode, as described in 2.3 Initiating a Transformation. Whenever an xsl:apply-templates instruction is evaluated, the current mode becomes the mode selected by this instruction.
- current output URI
The current output URI is the URI associated with the principal result or secondary result that is currently being written.
- current template rule
At any point in the processing of a stylesheet, there may be a current template rule. Whenever a template rule is chosen as a result of evaluating xsl:apply-templates, xsl:apply-imports, or xsl:next-match, the template rule becomes the current template rule for the evaluation of the rule’s sequence constructor.
- decimal format
All the xsl:decimal-format declarations in a package that share the same name are grouped into a named decimal format; those that have no name are grouped into a single unnamed decimal format.
- declaration
Top-level elements fall into two categories: declarations, and user-defined data elements. Top-level elements whose names are in the XSLT namespace are declarations. Top-level elements in any other namespace are user-defined data elements (see 3.6.4 User-defined Data Elements)
- declaration order
The declarations within a stylesheet level have a total ordering known as declaration order. The order of declarations within a stylesheet level is the same as the document order that would result if each stylesheet module were inserted textually in place of the xsl:include element that references it.
- declaring package
The declaring package of a component is the package that contains the declaration (or, in the case of xsl:attribute-set and xsl:key, multiple declarations) of the component.
- default collation
In this specification the term default collation means the collation that is used by XPath operators such as eq and lt appearing in XPath expressions within the stylesheet.
- default mode
The [xsl:]default-mode attribute defines the default mode, which is used as the default value for the mode attribute of all xsl:template and xsl:apply-templates elements within its scope.
- default priority
If no priority attribute is specified on an xsl:template element, a default priority is computed, based on the syntactic form of the pattern supplied in the match attribute.
- defining element
A string in the form of a lexical QName may occur as the value of an attribute node in a stylesheet module, or within an XPath expression contained in an attribute or text node within a stylesheet module, or as the result of evaluating an XPath expression contained in such a node. The element containing this attribute or text node is referred to as the defining element of the lexical QName.
- deprecated
Some constructs defined in this specification are described as being deprecated. The use of this term implies that stylesheet authors should not use the construct, and that the construct may be removed in a later version of this specification.
- disqualifying element
The disqualifying elements are xsl:map, xsl:map-entry, xsl:array, xsl:array-member, xsl:record, and xsl:select. If a sequence constructor includes one of these elements, then construction of the implicit document node does not take place.
- dynamic error
An error that is not capable of detection until a source document is being transformed is referred to as a dynamic error.
- eclipsed
An xsl:function declaration F is said to be eclipsed if the containing package includes an xsl:function declaration G such that F and G have the same name, F has lower import precedence than G, and the arity range of G includes the totality of the arity range of F.
- effective value
The effective value of an attribute or text node in the stylesheet is the value after any required expansion or normalization.
- effective version
The effective version of an element in a stylesheet module or package manifest is the decimal value of the [xsl:]version attribute (see 3.3 Standard Attributes) on that element or on the innermost ancestor element that has such an attribute, subject to special rules for the xsl:output and xsl:fallback elements.
- embedded stylesheet module
A stylesheet module whose outermost element is the child of a non-XSLT element in a host document is referred to as an embedded stylesheet module. See 3.11 Embedded Stylesheet Modules.A stylesheet module whose outermost element is the child of a non-XSLT element in a host document is referred to as an embedded stylesheet module.A stylesheet module whose outermost element is the child of a non-XSLT element in a host document is referred to as an embedded stylesheet module. See 3.11 Embedded Stylesheet Modules.
- enclosing mode
A mode declared by an xsl:mode declaration that has one or more contained xsl:template declarations is referred to as an enclosing mode.
- EQName
An EQName is a string representing an expanded QName where the string, after removing leading and trailing whitespace, is in the form defined by the EQNameXP production in the XPath specification.
- expanded QName
An expanded QName is a value in the value space of the xs:QName datatype as defined in the XDM data model (see [XDM 4.0]): that is, a triple containing namespace prefix (optional), namespace URI (optional), and local name. Two expanded QNames are equal if the namespace URIs are the same (or both absent) and the local names are the same. The prefix plays no part in the comparison, but is used only if the expanded QName needs to be converted back to a string.
- explicit default
An explicit default for a parameter is indicated by the presence of either a select attribute or a non-empty sequence constructor.
- explicitly mandatory
A parameter is explicitly mandatory if it is a function parameterwith no required attribute, or if the required attribute is present and has the value yes.
- expression
Within this specification, the term XPath expression, or simply expression, means a string that matches the production ExprXP defined in [XPath 4.0].
- extension attribute
An extension attribute is an attribute appearing on an XSLT element, where the name of the attribute is in a non-null namespace other than the XSLT namespace.
- extension function
An extension function is a named function introduced to the static or dynamic context by mechanisms outside the scope of this specification.
- extension instruction
An extension instruction is an element within a sequence constructor that is in a namespace (not the XSLT namespace) designated as an extension namespace.
- extension namespace
The extension instruction mechanism allows namespaces to be designated as extension namespaces. When a namespace is designated as an extension namespace and an element with a name from that namespace occurs in a sequence constructor, then the element is treated as an instruction rather than as a literal result element.
- final output state
The first of the two output states is called final output state. This state applies when instructions are writing to a final result tree.
- final result tree
A final result tree is a result tree that forms part of the output of a transformation: specifically, a tree built by post-processing the items in the principal result or in a secondary result. Once created, the contents of a final result tree are not accessible within the stylesheet itself.
- fixed namespace bindings
The fixed namespace bindings for a stylesheet module are established using the fixed-namespaces attribute on the xsl:stylesheet, xsl:transform, or xsl:package element enclosing the stylesheet module.
- focus
When a sequence constructor is evaluated, the processor keeps track of which items are being processed by means of a set of implicit variables referred to collectively as the focus.
- forwards compatible behavior
An element is processed with forwards compatible behavior if its effective version is greater than 4.0.
- function definition
The term function definition is defined in [XPath 4.0] section 2.2.1 Static Context. It is the definition of a function that can be called statically from within an XPath expression: in the case of XSLT it typically means either a stylesheet function, or a built-in function such as those defined in [Functions and Operators 4.0]
- function parameter
An xsl:param element may appear as a child of an xsl:function element, before any non-xsl:param children of that element. Such a parameter is known as a function parameter. A function parameter is a local variable with the additional property that its value can be set when the function is called, using a function call in an XPath expression.
- global context item
An item that is the global context item for the transformation acts as the context item when evaluating the select expression or sequence constructor of a global variablewhose declaration is within the top-level package, as described in 5.3.3.1 Maintaining Position: the Focus. The global context item may also be available in a named template when the stylesheet is invoked as described in 2.3.4 Call-Template Invocation
- global variable
A top-levelvariable-binding element declares a global variable that is visible everywhere except within any region where it is shadowed by another variable binding.
- GNode pattern
An GNode pattern uses a subset of the syntax for path expressions, and is defined to match a GNode if the corresponding path expression would select the GNode.
- group
The xsl:for-each-group instruction allocates the items in an input sequence into groups of items (that is, it establishes a collection of sequences) based either on common values of a grouping key, or on a pattern that the initial or final item in a group must match.
- grouping key
If the group-by or group-adjacent attributes is present, then for each item in the population a set of grouping keys is calculated, as follows: the expression contained in the group-by or group-adjacent attribute is evaluated; the result is atomized; and any xs:untypedAtomic items are cast to xs:string. If composite="yes" is specified, there is a single grouping key whose value is the resulting sequence; otherwise, there is a set of grouping keys, consisting of the distinct atomic items present in the result sequence.
- high priority package location
A xsl:package-location without the attribute is-priority, or with is-priority set to true is a high priority package location.
- homonymous
Two components are said to be homonymous if they have the same symbolic identifier.
- identical (types)
Types S and T are considered identical for the purpose of these rules if and only if subtype(S, T) and subtype(T, S) both hold, where the subtype relation is defined in [XPath 4.0] section 3.3.1 Subtypes of Sequence Types.
- immediate result
The result of evaluating a sequence constructor is the sequence of items formed by concatenating the results of evaluating each of the nodes in the sequence constructor, retaining order. This is referred to as the immediate result of the sequence constructor.
- implementation
A specific product that performs the functions of an XSLT processor is referred to as an implementation.
- implementation-defined
In this specification, the term implementation-defined refers to a feature where the implementation is allowed some flexibility, and where the choices made by the implementation must be described in documentation that accompanies any conformance claim.
- implementation-dependent
The term implementation-dependent refers to a feature where the behavior may vary from one implementation to another, and where the vendor is not expected to provide a full specification of the behavior.
- implicit default
If a parameter that is not explicitly mandatory has no explicit default value, then it has an implicit default value, which is the empty sequence if there is an as attribute, or a zero-length string if not.
- implicitly mandatory
If a parameter has an implicit default value which cannot be converted to the required type (that is, if it has an as attribute which does not permit the empty sequence), then the parameter is implicitly mandatory.
- import precedence
A declarationD in the stylesheet is defined to have lower import precedence than another declaration E if the stylesheet level containing D would be visited before the stylesheet level containing E in a post-order traversal of the import tree (that is, a traversal of the import tree in which a stylesheet level is visited after its children). Two declarations within the same stylesheet level have the same import precedence.
- import tree
The stylesheet levels making up a stylesheet are treated as forming an import tree. In the import tree, each stylesheet level has one child for each xsl:import declaration that it contains.
- initial function
A stylesheet may be evaluated by calling a named stylesheet function, referred to as the initial function.
- initial item
For each group, the item within the group that is first in population order is known as the initial item of the group.
- initial match selection
A stylesheet may be evaluated by supplying a value to be processed, together with an initial mode. The value (which can be any sequence of items) is referred to as the initial match selection. The processing then corresponds to the effect of the xsl:apply-templates instruction.
- initial mode
The initial mode is the mode used to select template rules for processing items in the initial match selection when apply-templates invocation is used to initiate a transformation.
- initial named template
A stylesheet may be evaluated by selecting a named template to be evaluated; this is referred to as the initial named template.
- initial sequence
The sequence to be sorted is referred to as the initial sequence.
- initial setting
The initial setting of a component of the dynamic context is used when evaluating global variables and stylesheet parameters, when evaluating the use and match attributes of xsl:key, and when evaluating the initial-value of xsl:accumulator and the select expressions or contained sequence constructors of xsl:accumulator-rule
- in-scope schema component
The schema components that may be referenced by name in a package are referred to as the in-scope schema components.
- instruction
An instruction is either an XSLT instruction or an extension instruction.
- invocation construct
The following constructs are classified as invocation constructs: the instructions xsl:call-template, xsl:apply-templates, xsl:apply-imports, and xsl:next-match; XPath function calls that bind to stylesheet functions; XPath dynamic function calls; the functions accumulator-before and accumulator-after; the [xsl:]use-attribute-sets attribute. These all have the characteristic that they can cause evaluation of constructs that are not lexically contained within the calling construct.
- key
A key is defined as a set of xsl:key declarations in the same package that share the same name.
- key specifier
The expression in the use attribute and the sequence constructor within an xsl:key declaration are referred to collectively as the key specifier. The key specifier determines the values that may be used to find a node using this key.
- lexical QName
A lexical QName is a string representing an expanded QName where the string, after removing leading and trailing whitespace, is within the lexical space of the xs:QName datatype as defined in XML Schema (see [XML Schema Part 2]): that is, a local name optionally preceded by a namespace prefix and a colon.
- library package
Every package within a stylesheet, other than the top-level package, is referred to as a library package.
- literal namespace URI
A namespace URI in the stylesheet tree that is being used to specify a namespace URI in the result tree is called a literal namespace URI.
- literal result element
In a sequence constructor, an element in the stylesheet that does not belong to the XSLT namespace and that is not an extension instruction (see 24.3 Extension Instructions) is classified as a literal result element.
- local variable
As well as being allowed as a declaration, the xsl:variable element is also allowed in sequence constructors. Such a variable is known as a local variable.
- low priority package location
A xsl:package-location with is-priority set to false is a low priority package location.
- merge activation
A merge activation is a single evaluation of the sequence constructor contained within the xsl:merge-action element, which occurs once for each distinct combined merge key value.
- merge input sequence
A merge input sequence is an arbitrary sequenceDM of items which is already sorted according to the merge key specification for the corresponding merge source definition.
- merge key component
A merge key component specifies one component of a merge key specification; it corresponds to a single xsl:merge-key element in the stylesheet.
- merge key specification
A merge key specification consists of one or more adjacent xsl:merge-key elements which together define how the merge input sequences selected by a merge source definition are sorted. Each xsl:merge-key element defines one merge key component.
- merge key value
For each item in a merge input sequence, a value is computed for each merge key component within the merge key specification. The value computed for an item by using the Nth merge key component is referred to as the Nth merge key value of that item.
- merge source definition
A merge source definition is the definition of one kind of input to the merge operation. It selects zero or more merge input sequences, and it includes a merge key specification to define how the merge key values are computed for each such merge input sequence.
- mode
A mode is a set of template rules; when the xsl:apply-templates instruction selects a set of items for processing, it identifies the rules to be used for processing those items by nominating a mode, explicitly or implicitly.
- mode definition
All the xsl:mode declarations in a package that share the same name are grouped into a named mode definition; those that have no name are grouped into a single unnamed mode definition.
- named template
Templates can be invoked by name. An xsl:template element with a name attribute defines a named template.
- namespace fixup
The rules for the individual XSLT instructions that construct a result tree (see 11 Creating Nodes) prescribe some of the situations in which namespace nodes are written to the tree. These rules, however, are not sufficient to ensure that the prescribed constraints are always satisfied. The XSLT processor must therefore add additional namespace nodes to satisfy these constraints. This process is referred to as namespace fixup.
- native namespace bindings
The native namespace bindings for any element in an XSLT stylesheet module are the prefix-uri mappings defined by the namespace nodes of that element, according to the rules in [XDM 4.0].
- non-contextual function call
The term non-contextual function call is used to refer to function calls that do not pass the dynamic context to the called function. This includes all calls on stylesheet functions and all dynamic function callsXP, (that is calls to function items). It excludes calls to some functions in the namespace http://www.w3.org/2005/xpath-functions, in particular those that explicitly depend on the context, such as the current-group and regex-group functions. It is implementation-defined whether, and under what circumstances, calls to extension functions are non-contextual.
- non-schema-aware processor
A non-schema-aware processor is a processor that does not claim conformance with the schema-aware conformance feature. Such a processor must handle constructs associated with schema-aware processing as described in this section.
- order of first appearance
There is a total ordering among groups referred to as the order of first appearance. A group G is defined to precede a group H in order of first appearance if the initial item of G precedes the initial item of H in population order. If two groups G and H have the same initial item (because the item is in both groups) then G precedes H if the grouping key of G precedes the grouping key of H in the sequence that results from evaluating the group-by expression of this initial item.
- output definition
All the xsl:output declarations within a package that share the same name are grouped into a named output definition; those that have no name are grouped into a single unnamed output definition.
- output state
Each instruction in the stylesheet is evaluated in one of two possible output states: final output state or temporary output state.
- override
A component in a using package may override a component in a used package, provided that the visibility of the component in the used package is either abstract or public. The overriding declaration is written as a child of the xsl:override element, which in turn appears as a child of xsl:use-package.
- package
An explicit package is represented by an xsl:package element, which will generally be the outermost element of an XML document. When the xsl:package element is not used explicitly, the entire stylesheet comprises a single implicit package.
- package manifest
The content of the xsl:package element is referred to as the package manifest
- parameter
The xsl:param element declares a parameter, which may be a stylesheet parameter, a template parameter, a function parameter, or an xsl:iterate parameter. A parameter is a variable with the additional property that its value can be set by the caller.
- pattern
A pattern specifies a set of conditions on an item. An item that satisfies the conditions matches the pattern; an item that does not satisfy the conditions does not match the pattern.
- picture string
The picture string is the string supplied as the second argument of the format-number function.
- place marker
The xsl:number instruction performs two tasks: firstly, determining a place marker (this is a sequence of integers, to allow for hierarchic numbering schemes such as 1.12.2 or 3(c)ii), and secondly, formatting the place marker for output as a text node in the result sequence.
- population
The sequence of items to be grouped, which is referred to as the population, is determined by evaluating the XPath expression contained in the select attribute.
- population order
The population is treated as a sequence; the order of items in this sequence is referred to as population order.
- portion
The integer literals and the optional NamePart within the version number are referred to as the portions of the version number.
- predicate pattern
A predicate pattern is written as . (dot) followed by zero or more predicates in square brackets, and it matches any item for which each of the predicates evaluates to true.
- principal result
A principal result: this can be any sequence of items (as defined in [XDM 4.0]).
- principal stylesheet module
Within a package, one stylesheet module functions as the principal stylesheet module. The complete package is assembled by finding the stylesheet modules referenced directly or indirectly from the principal stylesheet module using xsl:include and xsl:import elements: see 3.10.2 Stylesheet Inclusion and 3.10.3 Stylesheet Import.
- priority
The priority of a template rule is specified by the priority attribute on the xsl:template declaration. If no priority is specified explicitly for a template rule, its default priority is used, as defined in 6.3.3 Default Priority for Patterns.
- priority package location
The first package location whose value of href, when resolved as described in 5.8 URI References, allows the system to find the specified resource, and its entry if the resource is an archive, is the optimal package location.
- processing order
There is another total ordering among groups referred to as processing order. If group R precedes group S in processing order, then in the result sequence returned by the xsl:for-each-group instruction the items generated by processing group R will precede the items generated by processing group S.
- processor
The software responsible for transforming source trees into result trees using an XSLT stylesheet is referred to as the processor. This is sometimes expanded to XSLT processor to avoid any confusion with other processors, for example an XML processor.
- raw result
The result of invoking the selected component, after any required conversion to the declared result type of the component, is referred to as the raw result.
- reference binding
The process of identifying the component to which a symbolic reference applies (possibly chosen from several homonymous alternatives) is called reference binding.
- required type
The context within a stylesheet where an XPath expression appears may specify the required type of the expression. The required type indicates the type of the value that the expression is expected to return.
- reserved namespace
The XSLT namespace, together with certain other namespaces recognized by an XSLT processor, are classified as reserved namespaces and must be used only as specified in this and related specifications.
- result tree
The term result tree is used to refer to any tree constructed by instructions in the stylesheet. A result tree is either a final result tree or a temporary tree.
- schema-aware XSLT processor
A schema-aware XSLT processor is an XSLT processor that implements the mandatory requirements of this specification connected with the xsl:import-schema declaration, the [xsl:]validation and [xsl:]type attributes, and the ability to handle input documents whose nodes have type annotations other than xs:untyped and xs:untypedAtomic. The mandatory requirements of this specification are taken to include the mandatory requirements of XPath 4.0, as described in [XPath 4.0]. A requirement is mandatory unless the specification includes wording (such as the use of the words should or may) that clearly indicates that it is optional.
- schema component
Type definitions and element and attribute declarations are referred to collectively as schema components.
- schema instance namespace
The schema instance namespacehttp://www.w3.org/2001/XMLSchema-instance, with conventional prefix xsi, is used as defined in [XML Schema Part 1]
- schema namespace
The schema namespacehttp://www.w3.org/2001/XMLSchema, with conventional prefix xs, is used as defined in [XML Schema Part 1]
- secondary result
Zero or more secondary results: each secondary result can be any sequence of items (as defined in [XDM 4.0]).
- sequence constructor
A sequence constructor is a sequence of zero or more sibling nodes in the stylesheet that can be evaluated to return a sequence of nodes, atomic items, and function items. The way that the resulting sequence is used depends on the containing instruction.
- SequenceType
A SequenceType constrains the type and number of items in a sequence. The term is used both to denote the concept, and to refer to the syntactic form in which sequence types are expressed in the XPath grammar: specifically SequenceTypeXP in [XPath 4.0].
- serialization
A frequent requirement is to output a final result tree as an XML document (or in other formats such as HTML). This process is referred to as serialization.
- serialization error
If a transformation has successfully produced a principal result or secondary result, it is still possible that errors may occur in serializing that result . For example, it may be impossible to serialize the result using the encoding selected by the user. Such an error is referred to as a serialization error.
- serialization feature
A processor that claims conformance with the serialization featuremust support the conversion of a final result tree to a sequence of octets following the rules defined in 26 Serialization.
- shadows
Within a region of the stylesheet where a binding B1 is visible, B1 shadows another binding B2 having the same name as B1 if B1 occurs at a point where B2 is visible.
- simplified stylesheet
A simplified stylesheet, which is a subtree rooted at a literal result element, as described in 3.7 Simplified Stylesheet Modules. This is first converted to a standard stylesheet module by wrapping it in an xsl:stylesheet element using the transformation described in 3.7 Simplified Stylesheet Modules.
- singleton focus
A singleton focus based on an item J has the context item (and therefore the context node, if J is a node) set to J, and the context position and context size both set to 1 (one).
- snapshot
A snapshot of a node N is a deep copy of N, as produced by the xsl:copy-of instruction with copy-namespaces set to yes, copy-accumulators set to yes, and validation set to preserve, with the additional property that for every ancestor of N, the copy also has a corresponding ancestor whose name, node-kind, and base URI are the same as the corresponding ancestor of N, and that has copies of the attributes, namespaces and accumulator values of the corresponding ancestor of N. But the ancestor has a type annotation of xs:anyType, has the properties nilled, is-id, and is-idref set to false, and has no children other than the child that is a copy of N or one of its ancestors.
- sorted sequence
The sequence after sorting as defined by the xsl:sort elements is referred to as the sorted sequence.
- sort key component
Within a sort key specification, each xsl:sort element defines one sort key component.
- sort key specification
A sort key specification is a sequence of one or more adjacent xsl:sort elements which together define rules for sorting the items in an input sequence to form a sorted sequence.
- sort key value
For each item in the initial sequence, a value is computed for each sort key component within the sort key specification. The value computed for an item by using the Nth sort key component is referred to as the Nth sort key value of that item.
- source tree
The term source tree means any tree provided as input to the transformation. This includes the document containing the global context item if any, documents containing nodes present in the initial match selection, documents containing nodes supplied as the values of stylesheet parameters, documents obtained from the results of functions such as document, doc, and collection, documents read using the xsl:source-document instruction, and documents returned by extension functions or extension instructions. In the context of a particular XSLT instruction, the term source tree means any tree provided as input to that instruction; this may be a source tree of the transformation as a whole, or it may be a temporary tree produced during the course of the transformation.
- stable
A sort key specification is said to be stable if its first xsl:sort element has no stable attribute, or has a stable attribute whose effective value is yes.
- standard attributes
There are a number of standard attributes that may appear on any XSLT element: specifically default-collation, default-mode, default-validation, exclude-result-prefixes, expand-text, extension-element-prefixes, schema-role, use-when, version, and xpath-default-namespace.
- standard error namespace
The standard error namespacehttp://www.w3.org/2005/xqt-errors, with conventional prefix err, is used for error codes defined in this specification and related specifications. It is also used for the names of certain predefined variables accessible within the scope of an xsl:catch element.
- standard function namespace
The standard function namespacehttp://www.w3.org/2005/xpath-functions, with conventional prefix fn, is used for functions in the function library defined in [Functions and Operators 4.0] and for standard functions defined in this specification.
- standard stylesheet module
A standard stylesheet module, which is a subtree rooted at an xsl:stylesheet or xsl:transform element.
- static error
An error that can be detected by examining a stylesheet before execution starts (that is, before the source document and values of stylesheet parameters are available) is referred to as a static error.
- static expression
A static expression is an XPath expression whose value must be computed during static analysis of the stylesheet.
- static parameter
A static variable declared using an xsl:param element is referred to as a static parameter.
- static variable
A top-levelvariable-binding element having the attribute static="yes" declares a static variable: that is, a global variable whose value is known during static analysis of the stylesheet.
- streamable mode
A streamable mode is a mode that is declared in an xsl:mode declaration with the attribute streamable="yes".
- streamed document
A streamed document is a source tree that is processed using streaming, that is, without constructing a complete tree of nodes in memory.
- streamed node
A streamed node is a node in a streamed document.
- streaming
The term streaming refers to a manner of processing in which XML documents (such as source and result documents) are not represented by a complete tree of nodes occupying memory proportional to document size, but instead are processed “on the fly” as a sequence of events, similar in concept to the stream of events notified by an XML parser to represent markup in lexical XML.
- streaming feature
A processor that claims conformance with the streaming featuremust use streamed processing in cases where (a) streaming is requested (for example by using the attribute streamable="yes" on xsl:mode, or on the xsl:source-document instruction) and (b) the constructs in question are guaranteed-streamableSG according to this specification.
- string value
The term string value is defined in [XDM 4.0] section 7.6.12 string-value Accessor. Every node has a string value. For example, the string value of an element is the concatenation of the string values of all its descendant text nodes.
- stylesheet
A stylesheet consists of one or more packages: specifically, one top-level package and zero or more library packages.
- stylesheet function
An xsl:function declaration declares the name, parameters, and implementation of a family of stylesheet functions that can be called from any XPath expression within the stylesheet (subject to visibility rules).
- stylesheet level
A stylesheet level is a collection of stylesheet modules connected using xsl:include declarations: specifically, two stylesheet modules A and B are part of the same stylesheet level if one of them includes the other by means of an xsl:include declaration, or if there is a third stylesheet module C that is in the same stylesheet level as both A and B.
- stylesheet module
A package consists of one or more stylesheet modules, each one forming all or part of an XML document.
- stylesheet parameter
A top-levelxsl:param element declares a stylesheet parameter. A stylesheet parameter is a global variable with the additional property that its value can be supplied by the caller when a transformation is initiated.
- supplied value
The value of the variable is computed using the expression given in the select attribute or the contained sequence constructor, as described in 9.3 Values of Variables and Parameters. This value is referred to as the supplied value of the variable.
- symbolic identifier
The symbolic identifier of a component is a composite name used to identify the component uniquely within a package. The symbolic identifier comprises the kind of component (stylesheet function, named template, accumulator, attribute set, global variable, key, or mode), the expanded QName of the component (namespace URI plus local name), and in the case of stylesheet functions, the upper bound of the arity range.
- symbolic reference
The declaration of a component includes constructs that can be interpreted as references to other components by means of their symbolic identifiers. These constructs are generically referred to as symbolic references. Examples of constructs that give rise to symbolic references are the name attribute of xsl:call-template; the [xsl:]use-attribute-sets attribute of xsl:copy, xsl:element, and literal result elements; the explicit or implicit mode attribute of xsl:apply-templates; XPath variable references referring to global variables; XPath static function calls (including partial function applications) referring to stylesheet functions; and named function references (example: my:f#1) referring to stylesheet functions.
- tail position
An instructionJ is in a tail position within a sequence constructorSC if it satisfies one of the following conditions:
- target expression
The string that results from evaluating the expression in the xpath attribute is referred to as the target expression.
- target namespace URI
The namespace URI that is to be used in the result tree as a substitute for a literal namespace URI is called the target namespace URI.
- template
An xsl:template declaration defines a template, which contains a sequence constructor; this sequence constructor is evaluated to determine the result of the template. A template can serve either as a template rule, invoked by matching items against a pattern, or as a named template, invoked explicitly by name. It is also possible for the same template to serve in both capacities.
- template parameter
An xsl:param element may appear as a child of an xsl:template element, before any non-xsl:param children of that element. Such a parameter is known as a template parameter. A template parameter is a local variable with the additional property that its value can be set when the template is called, using any of the instructions xsl:call-template, xsl:apply-templates, xsl:apply-imports, or xsl:next-match.
- template rule
A stylesheet contains a set of template rules (see 6 Template Rules). A template rule has three parts: a pattern that is matched against selected items (often but not necessarily nodes), a (possibly empty) set of template parameters, and a sequence constructor that is evaluated to produce a sequence of items.
- temporary output state
The second of the two output states is called temporary output state. This state applies when instructions are writing to a temporary tree or any other non-final destination.
- temporary tree
The term temporary tree means any tree that is neither a source tree nor a final result tree.
- text value template
In a text node that is designated as a text value template, expressions can be used by surrounding each expression with curly brackets ({}).
- top-level
An element occurring as a child of an xsl:package, xsl:stylesheet, xsl:transform, or xsl:override element is called a top-level element.
- top-level package
For a given transformation, one package functions as the top-level package. The complete stylesheet is assembled by finding the packages referenced directly or indirectly from the top-level package using xsl:use-package declarations: see 3.4.2 Dependencies between Packages.
- traversal
A traversal of a tree is a sequence of traversal events.
- traversal-event
a traversal event (shortened to event in this section) is a pair comprising a phase (start or end) and a node.
- tree
The term tree is used (as in [XDM 4.0]) to refer to the aggregate consisting of a parentless node together with all its descendant nodes, plus all their attributes and namespaces.
- tunnel parameter
A parameter passed to a template may be defined as a tunnel parameter. Tunnel parameters have the property that they are automatically passed on by the called template to any further templates that it calls, and so on recursively.
- type annotation
The term type annotation is used in this specification to refer to the value returned by the dm:type-name accessor of a node: see [XDM 4.0] section 7.6.13 type-name Accessor.
- typed value
The term typed value is defined in [XDM 4.0] section 7.6.14 typed-value Accessor. Every node, other than an element whose type annotation identifies it as having element-only content, has a typed value. For example, the typed value of an attribute of type xs:IDREFS is a sequence of zero or more xs:IDREF values.
- type error
Certain errors are classified as type errors. A type error occurs when the value supplied as input to an operation is of the wrong type for that operation, for example when an integer is supplied to an operation that expects a node.
- type pattern
A type pattern is written as ~T (where T is an ItemTypeXP) followed by zero or more predicates in square brackets, and it matches any item of type T for which each of the predicates evaluates to true.
- unnamed mode
The unnamed mode is the default mode used when no mode attribute is specified on an xsl:apply-templates instruction or xsl:template declaration, unless a different default mode has been specified using the [xsl:]default-mode attribute of a containing element.
- URI Reference
Within this specification, the term URI Reference, unless otherwise stated, refers to a string in the lexical space of the xs:anyURI datatype as defined in [XML Schema Part 2].
- use
If a package Q contains an xsl:use-package element that references package P, then package Q is said to use package P. In this relationship package Q is referred to as the using package, package P as the used package.
- user-defined data element
In addition to declarations, the xsl:stylesheet element may contain among its children any element not from the XSLT namespace, provided that the expanded QName of the element has a non-null namespace URI. Such elements are referred to as user-defined data elements.
- vacuous
An item is vacuous if it is one of the following: a zero-length text node; a document node with no children; an atomic item which, on casting to xs:string, produces a zero-length string; or an array which on flattening using the array:flatten function produces either an empty sequence or a sequence consisting entirely of vacuous items.
- value
A variable is a binding between a name and a value. The value of a variable is any sequence (of nodes, atomic items, and/or function items), as defined in [XDM 4.0].
- value template
Collectively, attribute value templates and text value templates are referred to as value templates.
- variable
The xsl:variable element declares a variable, which may be a global variable or a local variable.
- variable-binding element
The two elements xsl:variable and xsl:param are referred to as variable-binding elements.
- visibility
The visibility of a component is one of: private, public, abstract, final, or hidden.
- whitespace text node
A whitespace text node is a text node whose content consists entirely of whitespace characters (that is, U+0009 (TAB) , U+000A (NEWLINE) , U+000D (CARRIAGE RETURN) , or U+0020 (SPACE) ).
- XML namespace
The XML namespace, defined in [Namespaces in XML] as http://www.w3.org/XML/1998/namespace, is used for attributes such as xml:lang, xml:space, and xml:id.
- XPath 1.0 compatibility mode
The term XPath 1.0 compatibility mode is defined in [XPath 4.0] section 2.2.1 Static Context. This is a setting in the static context of an XPath expression; it has two values, true and false. When the value is set to true, the semantics of function calls and certain other operations are adjusted to give a greater degree of backwards compatibility between XPath 4.0 and XPath 1.0.
- XSLT 1.0 behavior
An element in the stylesheet is processed with XSLT 1.0 behavior if its effective version is equal to 1.0.
- XSLT 1.0 compatibility feature
A processor that claims conformance with the XSLT 1.0 compatibility featuremust support the processing of stylesheet instructions and XPath expressions with XSLT 1.0 behavior, as defined in 3.8 Backwards Compatible Processing.
- XSLT 2.0 behavior
An element is processed with XSLT 2.0 behavior if its effective version is equal to 2.0.
- XSLT 3.0 behavior
An element is processed with XSLT 3.0 behavior if its effective version is equal to 3.0.
- XSLT element
An XSLT element is an element in the XSLT namespace whose syntax and semantics are defined in this specification.
- XSLT instruction
An XSLT instruction is an XSLT element whose syntax summary in this specification contains the annotation <!-- category: instruction -->.
- XSLT namespace
The XSLT namespace has the URI http://www.w3.org/1999/XSL/Transform. It is used to identify elements, attributes, and other names that have a special meaning defined in this specification.