Definitions extracted from the XPath 3.1 draft

For ease of comparison to other materials, I have extracted the definitions listed below from http://www.w3.org/TR/2014/CR-xpath-31-20141218/, an XPath 3.1 draft.

The definitions are bounded by "[" and "]" markers (except in one case that I suspect is an editorial error noted below). I have included any notes or material within a paragraph following definitions. Most likely some, if not all, of that material should appear in notes.

Not all definitions were in separate paragraphs but I have separated them into separate paragraphs for ease of reading. The definitions appear in title attribute sort order, ignoring case distinctions and sort failures in the glossary.

My comments are colored red

This is version 0.1 of this document. Dated 12 January 2015.

Comments to: Patrick Durusau

[Definition: An argument to a function call is either an argument expression or an ArgumentPlaceholder ("?").] If the EQName in a static function call is a lexical QName that has no namespace prefix, it is considered to be in the default function namespace.

[Definition: Argument expressions are evaluated with respect to DC, producing argument values.] The order of argument evaluation is implementation-dependent and a function need not evaluate an argument if the function can evaluate its body without evaluating that argument.

[Definition: The number of Arguments in an ArgumentList is its arity. ]

[Definition: An array is a function that associates a set of positions, represented as positive integer keys, with values.] The first position in an array is associated with the integer

[Definition: An arrow operator is a postfix operator that applies a function to an item, using the item as the first argument to the function.] If $s is a sequence and f() is a function, then $s=>f() is equivalent to f($s), and $s=>f($j) is equivalent to f($s, $j).

[Definition: The value associated with a given key is called the associated value of the key.]

[Definition: An atomic value is a value in the value space of an atomic type, as defined in [XML Schema 1.0] or [XML Schema 1.1].]

[Definition: Atomization of a sequence is defined as the result of invoking the fn:data function on the sequence, as defined in [XQuery and XPath Functions and Operators 3.1].]

[Definition: 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.] The set of available documents is not limited to the set of statically known documents, and it may be empty.

If there are one or more URIs in available documents that map to a document node D, then the document-uri property of D must either be absent, or must be one of these URIs.

[Definition: Available node collections. This is a mapping of strings to sequences of nodes. Each string represents the absolute URI of a resource. The sequence of nodes represents the result of the fn:collection function when that URI is supplied as the argument. ] The set of available node collections is not limited to the set of statically known collections, and it may be empty.

For every document node D that is in the target of a mapping in available node collections, or that is the root of a tree containing such a node, the document-uri property of D must either be absent, or must be a URI U such that available documents contains a mapping from U to D.

[Definition: Available resource 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. ] There is no implication that the URIs in this sequence can be successfully dereferenced, or that the resources they refer to have any particular media type.

[Definition: 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.] The set of available text resources is not limited to the set of statically known documents, and it may be empty.

[Definition: An axis step returns a sequence of nodes that are reachable from the context node via a specified axis. Such a step has two parts: an axis, which defines the "direction of movement" for the step, and a node test, which selects nodes based on their kind, name, and/or type annotation.] If the context item is a node, an axis step returns a sequence of zero or more nodes; otherwise, a type error is raised [err:XPTY0020]. The resulting node sequence is returned in document order. An axis step may be either a forward step or a reverse step, followed by zero or more predicates.

[Definition: The built-in functions supported by XPath 3.1 are defined in [XQuery and XPath Functions and Operators 3.1].] Additional functions may be provided in the static context. XPath per se does not provide a way to declare named functions, but a host language may provide such a mechanism.

[Definition: 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 [XQuery and XPath Functions and Operators 3.1].]

[Definition: One way to construct a sequence is by using the comma operator, which evaluates each of its operands and concatenates the resulting sequences, in order, into a single result sequence.] Empty parentheses can be used to denote an empty sequence.

A sequence may contain duplicate items, but a sequence is never an item in another sequence. When a new sequence is created by concatenating two or more input sequences, the new sequence contains all the items of the input sequences and its length is the sum of the lengths of the input sequences.

[Definition: The constructor function for a given type is used to convert instances of other atomic 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?).]

The following examples illustrate the use of constructor functions:

[Definition: The context item is the item currently being processed.]

[Definition: Context item static type. This component defines the static type of the context item within the scope of a given expression.]

[Definition: When the context item is a node, it can also be referred to as the context node.]

[Definition: 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 the focus is defined, the value of the context position is an integer greater than zero. The context position is returned by the expression fn:position(). When an expression E1/E2 or E1[E2] is evaluated, the context position in the inner focus for an evaluation of E2 is the position of the context item in the sequence obtained by evaluating E1. The position of the first item in a sequence is always 1 (one). The context position is always less than or equal to the context size.

[Definition: The context size is the number of items in the sequence of items currently being processed.] Its value is always an integer greater than zero. The context size is returned by the expression fn:last(). When an expression E1/E2 or E1[E2] is evaluated, the context size in the inner focus for an evaluation of E2 is the number of items in the sequence obtained by evaluating E1.

[Definition: 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 invoked multiple times during the execution of an expression, this function always returns the same result.]

[Definition: XPath 3.1 operates on the abstract, logical structure of an XML document, rather than its surface syntax. This logical structure, known as the data model, is defined in [XQuery and XPath Data Model (XDM) 3.1].]

[Definition: decimal-separator specifies the character used for the decimal-separator-symbol; the default value is the period character (.)]

[Definition: 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.]

[Definition: 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.]

[Definition: Default element/type namespace. This is a namespace URI or absent^DM31. The namespace URI, if present, is used for any unprefixed QName appearing in a position where an element or type name is expected.] The URI value is whitespace normalized according to the rules for the xs:anyURI type in [XML Schema 1.0] or [XML Schema 1.1].

[Definition: Default function namespace. This is a namespace URI or absent^DM31. The namespace URI, if present, is used for any unprefixed QName appearing in a position where a function name is expected.] The URI value is whitespace normalized according to the rules for the xs:anyURI type in [XML Schema 1.0] or [XML Schema 1.1].

[Definition: 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.]

[Definition: Default node collection. This is the sequence of nodes that would result from calling the fn:collection function with no arguments.] The value of default collection may be initialized by the implementation.

[Definition: Default place. This is a geographical location used to identify the place where events happened (or will happen) when formatting dates and times using functions such as fn:format-date and fn:format-dateTime, 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.]

[Definition: Default resource collection. This is the sequence of URIs that would result from calling the fn:uri-collection function with no arguments.] The value of default resource collection may be initialized by the implementation.

[Definition: The delimiting terminal symbols are: "!", "!=", StringLiteral, "#", "$", "(", ")", "*", "+", (comma), "-", (dot), "..", "/", "//", (colon), "::", ":=", "<", "<<", "<=", "=", "=>", ">", ">=", ">>", "?", "@", BracedURILiteral, "[", "]", "{", "|", "||", "}" ] in appendix A

[Definition: digit-sign specifies the character used for the digit-sign in the picture string; the default value is the number sign character (#)]

[Definition: Informally, document order is the order in which nodes appear in the XML serialization of a document.]

[Definition: The dynamic context of an expression is defined as information that is available at the time the expression is evaluated.] If evaluation of an expression relies on some part of the dynamic context that is absent^DM31, a dynamic error is raised [err:XPDY0002].

[Definition: A dynamic error is an error that must be detected during the dynamic evaluation phase and may be detected during the static analysis phase. Numeric overflow is an example of a dynamic error . ]

[Definition: The dynamic evaluation phase is the phase during which the value of an expression is computed.] It occurs after completion of the static analysis phase.

[Definition: A dynamic function call consists of a base expression that returns the function and a parenthesized list of zero or more arguments (argument expressions or ArgumentPlaceholders).]

[Definition: A dynamic type is associated with each value as it is computed. The dynamic type of a value may be more specific than the static type of the expression that computed it (for example, the static type of an expression might be xs:integer*, denoting a sequence of zero or more integers, but at evaluation time its value may have the dynamic type xs:integer, denoting exactly one integer.)]

[Definition: The effective boolean value of a value is defined as the result of applying the fn:boolean function to the value, as defined in [XQuery and XPath Functions and Operators 3.1].]

[Definition: A sequence containing zero items is called an empty sequence.]

[Definition: Each key / value pair in a map is called an entry.]

[Definition: 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.]

[Definition: In addition to its identifying QName, a dynamic error may also carry a descriptive string and one or more additional values called error values.] An implementation may provide a mechanism whereby an application-defined error handler can process error values and produce diagnostic messages. XQuery 3.1 provides standard error handling via Section 3.16 Try/Catch Expressions ^XQ31 .

[Definition: An expanded QName consists of an optional namespace URI and a local name. An expanded QName also retains its original namespace prefix (if any), to facilitate casting the expanded QName into a string.] Two expanded QNames are equal if their namespace URIs are equal and their local names are equal (even if their namespace prefixes are not equal). Namespace URIs and local names are compared on a codepoint basis, without further normalization.

[Definition: exponent-separator Defines the character used to separate the mantissa from the exponent in scientific notation both in the picture string and in the formatted number; the default value is the character (e).]

[Definition: The expression context for a given expression consists of all the information that can affect the result of the expression.]

[Definition: An expression followed by a predicate (that is, E1[E2]) is referred to as a filter expression: its effect is to return those items from the value of E1 that satisfy the predicate in E2.]

[Definition: In a partial function application, a fixed position is an argument/parameter position for which the ArgumentList has an argument expression (as opposed to an ArgumentPlaceholder). ] (Note that a partial function application need not have any fixed positions.)

[Definition: The first three components of the dynamic context (context item, context position, and context size) are called the focus of the expression. ]

[Definition: Function coercion wraps a function^DM31 in a new function with signature the same as the expected type. This effectively delays the checking of the argument and return types until the function is invoked.]

[Definition: The function conversion rules are used to convert an argument value to its expected type; that is, to the declared type of the function parameter. ] The expected type is expressed as a sequence type. The function conversion rules are applied to a given value as follows:

[Definition: A generalized atomic type is a type which is either (a) an atomic type or (b) a pure union type ].

[Definition: In the operator mapping tables, the term Gregorian refers to the types xs:gYearMonth, xs:gYear, xs:gMonthDay, xs:gDay, and xs:gMonth.] For binary operators that accept two Gregorian-type operands, both operands must have the same type (for example, if one operand is of type xs:gDay, the other operand must be of type xs:gDay.)

[Definition: grouping-separator specifies the character used for the grouping-separator-symbol, which is typically used as a thousands separator; the default value is the comma character (,)]

[Definition: 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.2.4.2 Explicit Whitespace Handling).] Ignorable whitespace characters are not significant to the semantics of an expression. Whitespace is allowed before the first terminal and after the last terminal of an XPath. Whitespace is allowed between any two terminals. Comments may also act as "whitespace" to prevent two adjacent terminals from being recognized as one. Some illustrative examples are as follows:

[Definition: Implementation-defined indicates an aspect that may differ between implementations, but must be specified by the implementor for each particular implementation.]

[Definition: 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 implementor for any particular implementation.]

[Definition: 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 [XML Schema 1.0] or [XML Schema 1.1] for the range of valid values of a timezone.]

[Definition: 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). ]

[Definition: 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). ] An element declaration includes information about the element's substitution group affiliation.

[Definition: 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.]

[Definition: In-scope schema definitions. This 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.] It includes the following three parts: Rewrite to delete last sentence and to name the parts. BTW, there are 4 parts, not three, listed in the original In-scope schema definitions, In-scope element declaration, substitution groups, and In-scope attribute declarations. Should not use sub-lists in definitions as it makes the sub-definitions harder to find.

[Definition: 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 2.5.1 Predefined Schema Types. ]

[Definition: In-scope variables. This is a mapping from expanded QName to type. 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.]

An expression that binds a variable extends the in-scope variables, within the scope of the variable, with the variable and its type. Within the body of an inline function expression , the in-scope variables are extended by the names and types of the function parameters.

[Definition: infinity specifies the string used for the infinity-symbol; the default value is the string "Infinity"]

[Definition: The initial context item is a context item that an implementation can set before processing a query begins. The query body and the prolog of every module in a query share the same initial context item.]

[Definition: An inline function expression creates an anonymous function^DM31 defined directly in the inline function expression itself.] An inline function expression specifies the names and SequenceTypes of the parameters to the function, the SequenceType of the result, and the body of the function.

[Definition: An item is either an atomic value, a node, or a function^DM31.]

[Definition: An alternative form of a node test called a kind test can select nodes based on their kind, name, and type annotation.] The syntax and semantics of a kind test are described in 2.5.4 SequenceType Syntax and 2.5.5 SequenceType Matching. When a kind test is used in a node test, only those nodes on the designated axis that match the kind test are selected. Shown below are several examples of kind tests that might be used in path expressions:

[Definition: A lexical QName is a name that conforms to the syntax of [http://www.w3.org/TR/REC-xml-names/#NT-QName].]

[Definition: A literal is a direct syntactic representation of an atomic value.] XPath 3.1 supports two kinds of literals: numeric literals and string literals.

[Definition: A map is a function that associates a set of keys with values, resulting in a collection of key / value pairs.]

[Definition: The values of an array are called its members.] In the type hierarchy, array has a distinct type, which is derived from function. Atomization converts arrays to sequences (see Atomization).

[Definition: minus-sign specifies the character used for the minus-sign-symbol; the default value is the hyphen-minus character (-, #x2D). The value must be a single character.]

[Definition: A node test that consists only of an EQName or a Wildcard is called a name test.] A name test is true if and only if the kind of the node is the principal node kind for the step axis and the expanded QName of the node is equal (as defined by the eq operator) to the expanded QName specified by the name test. For example, child::para selects the para element children of the context node; if the context node has no para children, it selects an empty set of nodes. attribute::abc:href selects the attribute of the context node with the QName abc:href; if the context node has no such attribute, it selects an empty set of nodes.

[Definition: A named function is a function defined in the static context for the expression. To uniquely identify a particular named function, both its name as an expanded QName and its arity are required.]

[Definition: A named function reference denotes a named function.]

[Definition: Named functions. This is a mapping from (expanded QName, arity) to function^DM31. ] It supplies a function for each signature in statically known function signatures and may supply other functions (see 2.2.4 Consistency Constraints). Named functions can include functions with implementation-dependent implementations; these functions do not have a static context or a dynamic context of their own.

[Definition: 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.]

[Definition: NaN specifies the string used for the NaN-symbol, which is used to represent the value NaN (not-a-number); the default value is the string "NaN"]

[Definition: A node is an instance of one of the node kinds defined in [XQuery and XPath Data Model (XDM) 3.1].] Each node has a unique node identity, a typed value, and a string value. In addition, some nodes have a name. The typed value of a node is a sequence of zero or more atomic values. The string value of a node is a value of type xs:string. The name of a node is a value of type xs:QName.

[Definition: A node test is a condition on the name, kind (element, attribute, text, document, comment, or processing instruction), and/or type annotation of a node. A node test determines which nodes contained by an axis are selected by a step.]

[Definition: The non-delimiting terminal symbols are: IntegerLiteral, URIQualifiedName, NCName, DecimalLiteral, DoubleLiteral, QName, "ancestor", "ancestor-or-self", "and", "array", "as", "attribute", "cast", "castable", "child", "comment", "descendant", "descendant-or-self", "div", "document-node", "element", "else", "empty-sequence", "eq", "every", "except", "following", "following-sibling", "for", "function", "ge", "gt", "idiv", "if", "in", "instance", "intersect", "is", "item", "le", "let", "lt", "map", "mod", "namespace", "namespace-node", "ne", "node", "of", "or", "parent", "preceding", "preceding-sibling", "processing-instruction", "return", "satisfies", "schema-attribute", "schema-element", "self", "some", "text", "then", "to", "treat", "union" ]

[Definition: When referring to a type, the term numeric denotes the types xs:integer, xs:decimal, xs:float, and xs:double which are all member types of the built-in union type xs:numeric .] An operator whose operands and result are designated as numeric might be thought of as representing four operators, one for each of the numeric types. For example, the numeric + operator might be thought of as representing the following four operators:

[Definition: A predicate whose predicate expression returns a numeric type is called a numeric predicate.]

The and and or operators are defined directly in the main body of this document, and do not occur in the operator mapping tables. In appendix B. Normative but an odd place for it.

[Definition: A static or dynamic function call is a partial function application if one or more arguments is an ArgumentPlaceholder. ]

[Definition: A path expression can be used to locate nodes within trees. A path expression consists of a series of one or more steps, separated by "/" or "//", and optionally beginning with "/" or "//".] An initial "/" or "//" is an abbreviation for one or more initial steps that are implicitly added to the beginning of the path expression, as described below.

[Definition: pattern-separator specifies the character used for the pattern-separator-symbol, which separates positive and negative sub-pictures in a picture string; the default value is the semi-colon character (;)]

[Definition: per-mille specifies the character used for the per-mille-symbol; the default value is the Unicode per-mille character (#x2030)]

[Definition: percent specifies the character used for the percent-symbol; the default value is the percent character (%)]

[Definition: Primary expressions are the basic primitives of the language. They include literals, variable references, context item expressions, 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.]

[Definition: 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.] Thus:

[Definition: A pure union type is an XML Schema union type that satisfies the following constraints: (1) {variety} is union, (2) the {facets} property is empty, (3) no type in the transitive membership of the union type has {variety} list, and (4) no type in the transitive membership of the union type is a type with {variety} union having a non-empty {facets} property].

[Definition: 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).] During static analysis, the base URI is the Static Base URI. During dynamic evaluation, the base URI used to resolve a relative URI reference depends on the semantics of the expression. Bold should only highlight "resolve."

Any process that attempts to resolve URI against a base URI, or to dereference the URI, may apply percent-encoding or decoding as defined in the relevant RFCs.

[Definition: The node ordering that is the reverse of document order is called reverse document order.]

[Definition: Two atomic values K1 and K2 have the same key value if the relation deep-equal(K1, K2, $UCC) holds, where $UCC is the Unicode codepoint collation.] If two or more entries have the same key value then a dynamic error is raised [err:XQDY0137].

If the keys in a map constructor contain both date/time values with a timezone and date/time values with no timezone, a dynamic error is raised [err:XPDY0139]. The term "date/time value" here means an instance of any of the types xs:dateTime, xs:date, xs:time, xs:gYear, xs:gYearMonth, xs:gMonth, xs:gMonthDay, or xs:gDay.