XPath and XQuery Functions and Operators 4.0

B Error summarycodes

The error text provided with these errors is non-normative.

err:FOAP0001, Wrong number of arguments.

Raised when fn:apply is called and the arity of the supplied function is not the same as the number of members in the supplied array.

err:FOAR0001, Division by zero.

This error is raised whenever an attempt is made to divide by zero.

err:FOAR0002, Numeric operation overflow/underflow.

This error is raised whenever numeric operations result in an overflow or underflow.

err:FOAY0001, Array index out of bounds.

This error is raised when an integer used to select a member of an array is outside the range of values for that array.

err:FOAY0002, Negative array length.

This error is raised when the $length argument to array:subarray is negative.

err:FOCA0001, Input value too large for decimal.

Raised when casting to xs:decimal if the supplied value exceeds the implementation-defined limits for the datatype.

err:FOCA0002, Invalid lexical value.

Raised by fn:resolve-QName and fn:QName when a supplied value does not have the lexical form of a QName or URI respectively; and when casting to decimal, if the supplied value is NaN or Infinity.

err:FOCA0003, Input value too large for integer.

Raised when casting to xs:integer if the supplied value exceeds the implementation-defined limits for the datatype.

err:FOCA0005, NaN supplied as float/double value.

Raised when multiplying or dividing a duration by a number, if the number supplied is NaN.

err:FOCA0006, String to be cast to decimal has too many digits of precision.

Raised when casting a string to xs:decimal if the string has more digits of precision than the implementation can represent (the implementation also has the option of rounding).

err:FOCH0001, Codepoint not valid.

Raised by fn:codepoints-to-string if the input contains an integer that is not the codepoint of a permitted character.

err:FOCH0002, Unsupported collation.

Raised by any function that uses a collation if the requested collation is not recognized.

err:FOCH0003, Unsupported normalization form.

Raised by fn:normalize-unicode if the requested normalization form is not supported by the implementation.

err:FOCH0004, Collation does not support collation units.

Raised by functions such as fn:contains if the requested collation does not operate on a character-by-character basis.

err:FOCH0005, Unrecognized or invalid character name.

Raised by fn:char if the supplied character name is not recognized, or if it represents a codepoint that is not a permitted character.

err:FOCV0001, CSV field quoting error.

Raised when parsing CSV input if a syntax error in the input CSV is found.

err:FOCV0002, Invalid CSV delimiter error.

Raised when parsing CSV input if the field-separator, record-separator, or quote-character option is set to an invalid value.

err:FOCV0003, Duplicate CSV delimiter error.

Raised when parsing CSV input if the same delimiter character is assigned to more than one role.

err:FOCV0004, Argument supplied is not a known column name.

Raised by the function from the get entry of csv-columns-record, if its $key argument is an xs:string and is not one of the known column names.

err:FODC0001, No context document.

Raised by fn:id, fn:idref, and fn:element-with-id if the node that identifies the tree to be searched is a node in a tree whose root is not a document node.

err:FODC0002, Error retrieving resource.

Raised by fn:doc, fn:collection, and fn:uri-collection to indicate that either the supplied URI cannot be dereferenced to obtain a resource, or the resource that is returned is not parseable as XML.

err:FODC0003, Function not defined as deterministic.

Raised by fn:doc, fn:collection, and fn:uri-collection to indicate that it is not possible to return a result that is guaranteed deterministic.

err:FODC0004, Invalid collection URI.

Raised by fn:collection and fn:uri-collection if the argument is not a valid xs:anyURI.

err:FODC0005, Invalid URI reference.

Raised (optionally) by fn:doc if the argument is not a valid xs:anyURI.

err:FODC0006, String passed to fn:parse-xml is not a well-formed XML document.

Raised by fn:parse-xml if the supplied string is not a well-formed and namespace-well-formed XML document; or if DTD validation is requested and the document is not valid against its DTD.

err:FODC0007, String passed to fn:parse-xml is not a DTD-valid XML document.

Raised by fn:parse-xml if DTD validation is requested and the supplied string has no DTD or is not valid against the DTD.

err:FODC0008, Invalid value for the xsd-validation option of fn:parse-xml.

Raised when the xsd-validation option to fn:parse-xml is supplied, and the value is not one of the permitted values; for example if the option type Q{U}NNN is used, and Q{U}NNN does not identify a type in the static context.

err:FODC0009, Processor is not schema-aware.

Raised when the xsd-validation option to fn:parse-xml is set to a value other than skip, if the processor is not schema-aware.

err:FODC0010, The processor does not support serialization.

Raised when fn:serialize is called and the processor does not support serialization, in cases where the host language makes serialization an optional feature.

err:FODC0011, String passed to fn:parse-html is not a well-formed HTML document.

Raised by fn:parse-html if the supplied string is not a well-formed HTML document.

err:FODC0012, Unsupported HTML parser option.

Raised by fn:parse-html if a key passed to $options, or its value, is not supported by the implementation.

err:FODC0013, No validating XML parser available.

Raised when the dtd-validation option to fn:parse-xml is set, if no validating XML parser is available. Note: it is recommended that all processors should support the dtd-validation option, but there may be environments (such as web browsers) where this is not practically feasible.

err:FODC0014, String passed to fn:parse-xml is not a schema-valid XML document.

Raised by fn:parse-xml if XSD validation is requested and the XML document represented by the supplied string is not valid against the relevant XSD schema.

err:FODF1280, Invalid decimal format name.

This error is raised if the decimal format name supplied to fn:format-number is not a valid QName, or if the prefix in the QName is undeclared, or if there is no decimal format in the static context with a matching name.

err:FODF1290, Invalid decimal format property.

This error is raised if a decimal format value supplied to fn:format-number is not valid for the associated property, or if the properties of the decimal format resulting from a supplied map do not have distinct values.

err:FODF1310, Invalid decimal format picture string.

This error is raised if the picture string supplied to fn:format-number or fn:format-integer has invalid syntax.

err:FODT0001, Overflow/underflow in date/time operation.

Raised when casting to date/time datatypes, or performing arithmetic with date/time values, if arithmetic overflow or underflow occurs.

err:FODT0002, Overflow/underflow in duration operation.

Raised when casting to duration datatypes, or performing arithmetic with duration values, if arithmetic overflow or underflow occurs.

err:FODT0003, Invalid timezone value.

Raised by adjust-date-to-timezone and related functions if the supplied timezone is invalid.

err:FODT0004, No timezone data available

Raised by civil-timezone if no timezone data is available for the given date/time and place.

err:FOER0000, Unidentified error.

Error code used by fn:error when no other error code is provided.

err:FOFD1340, Invalid date/time formatting parameters.

This error is raised if the picture string or calendar supplied to fn:format-date, fn:format-time, or fn:format-dateTime has invalid syntax.

err:FOFD1350, Invalid date/time formatting component.

This error is raised if the picture string supplied to fn:format-date selects a component that is not present in a date, or if the picture string supplied to fn:format-time selects a component that is not present in a time.

err:FOHA0001, Invalid algorithm.

Raised by fn:hash if the effective value of the supplied algorithm is not one of the values supported by the implementation.

err:FOJS0001, JSON syntax error.

Raised by functions such as fn:json-doc, fn:parse-json or fn:json-to-xml if the string supplied as input does not conform to the JSON grammar (optionally with implementation-defined extensions).

err:FOJS0003, JSON duplicate keys.

Raised by functions such as map:merge, fn:json-doc, fn:parse-json or fn:json-to-xml if the input contains duplicate keys, when the chosen policy is to reject duplicates.

err:FOJS0004, JSON: not schema-aware.

Raised by fn:json-to-xml if validation is requested when the processor does not support schema validation or typed nodes.

err:FOJS0005, Invalid options.

Raised by functions such as map:merge, fn:parse-json, and fn:xml-to-json if the $options map contains an invalid entry.

err:FOJS0006, Invalid XML representation of JSON.

Raised by fn:xml-to-json if the XML input does not conform to the rules for the XML representation of JSON.

err:FOJS0007, Bad JSON escape sequence.

Raised by fn:xml-to-json if the XML input uses the attribute escaped="true" or escaped-key="true", and the corresponding string or key contains an invalid JSON escape sequence.

err:FONS0004, No namespace found for prefix.

Raised by fn:resolve-QName and analogous functions if a supplied QName has a prefix that has no binding to a namespace.

err:FONS0005, Base-uri not defined in the static context.

Raised by fn:resolve-uri if no base URI is available for resolving a relative URI.

err:FOQM0001, Module URI is a zero-length string.

Raised by fn:load-xquery-module if the supplied module URI is zero-length.

err:FOQM0002, Module URI not found.

Raised by fn:load-xquery-module if no module can be found with the supplied module URI.

err:FOQM0003, Static error in dynamically loaded XQuery module.

Raised by fn:load-xquery-module if a static error (including a statically detected type error) is encountered when processing the library module.

err:FOQM0005, Parameter for dynamically loaded XQuery module has incorrect type.

Raised by fn:load-xquery-module if a value is supplied for the initial context item or for an external variable, and the value does not conform to the required type declared in the dynamically loaded module.

err:FOQM0006, No suitable XQuery processor available.

Raised by fn:load-xquery-module if no XQuery processor is available supporting the requested XQuery version (or if none is available at all).

err:FORG0001, Invalid value for cast/constructor.

A general-purpose error raised when casting, if a cast between two datatypes is allowed in principle, but the supplied value cannot be converted: for example when attempting to cast the string "nine" to an integer.

err:FORG0002, Invalid argument to fn:resolve-uri.

Raised when either argument to fn:resolve-uri is not a valid URI/IRI.

err:FORG0003, fn:zero-or-one called with a sequence containing more than one item.

Raised by fn:zero-or-one if the supplied value contains more than one item.

err:FORG0004, fn:one-or-more called with a sequence containing no items.

Raised by fn:one-or-more if the supplied value is an empty sequence.

err:FORG0005, fn:exactly-one called with a sequence containing zero or more than one item.

Raised by fn:exactly-one if the supplied value is not a singleton sequence.

err:FORG0006, Invalid argument type.

Raised by functions such as fn:max, fn:min, fn:avg, fn:sum if the supplied sequence contains values inappropriate to this function.

err:FORG0008, The two arguments to fn:dateTime have inconsistent timezones.

Raised by fn:dateTime if the two arguments both have timezones and the timezones are different.

err:FORG0009, Error in resolving a relative URI against a base URI in fn:resolve-uri.

A catch-all error for fn:resolve-uri, recognizing that the implementation can choose between a variety of algorithms and that some of these may fail for a variety of reasons.

err:FORG0010, Invalid date/time.

Raised when the input to fn:parse-ietf-date does not match the prescribed grammar, or when it represents an invalid date/time such as 31 February.

err:FORG0011, Invalid radix.

Raised when the radix supplied to fn:parse-integer is not in the range 2 to 36.

err:FORG0012, Invalid digits.

Raised when the digits in the string supplied to fn:parse-integer are not in the range appropriate to the chosen radix.

err:FORG0013, Inconsistent options.

Raised if an inconsistent set of options is supplied in an option map.

err:FORX0001, Invalid regular expression flags.

Raised by regular expression functions such as fn:matches and fn:replace if the regular expression flags contain a character other than i, m, q, s, or x.

err:FORX0002, Invalid regular expression.

Raised by regular expression functions such as fn:matches and fn:replace if the regular expression is syntactically invalid.

err:FORX0003, Regular expression matches zero-length string.

For functions such as fn:replace and fn:tokenize, raises an error if the supplied regular expression is capable of matching a zero length string.

err:FORX0004, Invalid replacement string.

Raised by fn:replace to report errors in the replacement string.

err:FORX0005, Incompatible arguments for fn:replace.

Raised by fn:replace if both the $replacement and $action arguments are supplied.

err:FOTY0012, Argument to fn:data contains a node that does not have a typed value.

Raised by fn:data, or by implicit atomization, if applied to a node with no typed value, the main example being an element validated against a complex type that defines it to have element-only content.

err:FOTY0013, The argument to fn:data contains a function item.

Raised by fn:data, or by implicit atomization, if the sequence to be atomized contains a function item other than an array.

err:FOTY0014, The argument to fn:string is a function item.

Raised by fn:string, or by implicit string conversion, if the input sequence contains a function item.

err:FOUR0001, Invalid IPv6/IPvFuture authority

A dynamic error is raised if the authority component of a URI contains an open square bracket but no corresponding close square bracket.

err:FOUT1170, Invalid URI reference.

Raised by fn:unparsed-text or fn:unparsed-text-lines if the $source argument contains a fragment identifier, or if it cannot be resolved to an absolute URI (for example, because the base-URI property in the static context is absent), or if it cannot be used to retrieve the string representation of a resource.

err:FOUT1190, Cannot decode external resource.

Raised by fn:unparsed-text or fn:unparsed-text-lines if the $encoding argument is not a valid encoding name, if the processor does not support the specified encoding, if the string representation of the retrieved resource contains octets that cannot be decoded into Unicode characters using the specified encoding, or if the resulting characters are not permitted characters.

err:FOUT1200, Cannot infer encoding of external resource.

Raised by fn:unparsed-text or fn:unparsed-text-lines if the $encoding argument is absent and the processor cannot infer the encoding using external information and the encoding is not UTF-8.

err:FOXT0001, No suitable XSLT processor available

A dynamic error is raised if no XSLT processor suitable for evaluating a call on fn:transform is available.

err:FOXT0002, Invalid parameters to XSLT transformation

A dynamic error is raised if the parameters supplied to fn:transform are invalid, for example if two mutually exclusive parameters are supplied. If a suitable XSLT error code is available (for example in the case where the requested initial-template does not exist in the stylesheet), that error code should be used in preference.

err:FOXT0003, XSLT transformation failed

A dynamic error is raised if an XSLT transformation invoked using fn:transform fails with a static or dynamic error. The XSLT error code is used if available; this error code provides a fallback when no XSLT error code is returned, for example because the processor is an XSLT 1.0 processor.

err:FOXT0004, XSLT transformation has been disabled

A dynamic error is raised if the fn:transform function is invoked when XSLT transformation (or a specific transformation option) has been disabled for security or other reasons.

err:FOXT0006, XSLT output contains non-accepted characters

A dynamic error is raised if the result of the fn:transform function contains characters available only in XML 1.1 and the calling processor cannot handle such characters.

E Other FunctionsFunctions defined elsewhere (Non-Normative)

This Appendix describes some sources of functions that fall outside the scope of the function library defined in this specification. It includes both function specifications and function implementations. Inclusion of a function in this appendix does not constitute any kind of recommendation or endorsement; neither is omission from this appendix to be construed negatively. This Appendix does not attempt to give any information about licensing arrangements for these function specifications or implementations.

F Checklist of implementationImplementation-defined features (Non-Normative)

1. It is implementation-defined which version of Unicode is supported, but it is recommended that the most recent version of Unicode be used. (See Conformance.)

2. It is implementation-defined whether the type system is based on XML Schema 1.0 or XML Schema 1.1. (See Conformance.)

3. It is implementation-defined whether definitions that rely on XML (for example, the set of valid XML characters) should use the definitions in XML 1.0 or XML 1.1. (See Conformance.)

4. Implementations may attach an implementation-defined meaning to options in the map that are not described in this specification. These options should use values of type xs:QName as the option names, using an appropriate namespace. (See Options.)

5. It is implementation-defined which version of [The Unicode Standard] is supported, but it is recommended that the most recent version of Unicode be used. (See Strings, characters, and codepoints.)

6. [Definition] Some functions (such as fn:distinct-values, fn:unordered, map:keys, and map:for-each) produce results in an implementation-defined or implementation-dependent order. In such cases two calls with the same arguments are not guaranteed to produce the results in the same order. These functions are said to be nondeterministic with respect to ordering. (See Properties of functions.)

7. Where the results of a function are described as being (to a greater or lesser extent) implementation-defined or implementation-dependent, this does not by itself remove the requirement that the results should be deterministic: that is, that repeated calls with the same explicit and implicit arguments must return identical results. (See Properties of functions.)

8. In addition, the values of $input, typically serialized and converted to an xs:string, and $label (if supplied and non-empty) may be output to an implementation-defined destination. (See fn:trace.)

9. Consider a situation in which a user wants to investigate the actual value passed to a function. Assume that in a particular execution, $v is an xs:decimal with value 124.84. Writing fn:trace($v, 'the value of $v is:') will return $v. The processor may output "124.84" and "the value of $v is:" to an implementation-defined destination. (See fn:trace.)

10. Similar to fn:trace, the values of $input, typically serialized and converted to an xs:string, and $label (if supplied and non-empty) may be output to an implementation-defined destination. (See fn:message.)

11. They may provide an implementation-defined mechanism that allows users to choose between raising an error and returning a result that is modulo the largest representable integer value. See [ISO 10967]. (See Arithmetic operators on numeric values.)

12. For xs:decimal values, let N be the number of digits of precision supported by the implementation, and let M (M <= N) be the minimum limit on the number of digits required for conformance (18 digits for XSD 1.0, 16 digits for XSD 1.1). Then for addition, subtraction, and multiplication operations, the returned result should be accurate to N digits of precision, and for division and modulus operations, the returned result should be accurate to at least M digits of precision. The actual precision is implementation-defined. If the number of digits in the mathematical result exceeds the number of digits that the implementation retains for that operation, the result is truncated or rounded in an implementation-defined manner. (See Arithmetic operators on numeric values.)

13. The [IEEE 754-2019] specification also describes handling of two exception conditions called divideByZero and invalidOperation. The IEEE divideByZero exception is raised not only by a direct attempt to divide by zero, but also by operations such as log(0). The IEEE invalidOperation exception is raised by attempts to call a function with an argument that is outside the function’s domain (for example, sqrt(-1) or log(-1)). Although IEEE defines these as exceptions, it also defines “default non-stop exception handling” in which the operation returns a defined result, typically positive or negative infinity, or NaN. With this function library, these IEEE exceptions do not cause a dynamic error at the application level; rather they result in the relevant function or operator returning the defined non-error result. The underlying IEEE exception may be notified to the application or to the user by some implementation-defined warning condition, but the observable effect on an application using the functions and operators defined in this specification is simply to return the defined result (typically -INF, +INF, or NaN) with no error. (See Arithmetic operators on numeric values.)

14. The [IEEE 754-2019] specification distinguishes two NaN values: a quiet NaN and a signaling NaN. These two values are not distinguishable in the XDM model: the value spaces of xs:float and xs:double each include only a single NaN value. This does not prevent the implementation distinguishing them internally, and triggering different implementation-defined warning conditions, but such distinctions do not affect the observable behavior of an application using the functions and operators defined in this specification. (See Arithmetic operators on numeric values.)

15. The implementation may adopt a different algorithm provided that it is equivalent to this formulation in all cases where implementation-dependent or implementation-defined behavior does not affect the outcome, for example, the implementation-defined precision of the result of xs:decimal division. (See op:numeric-integer-divide.)

16. There may be implementation-defined limits on the precision available. If the requested $precision is outside this range, it should be adjusted to the nearest value supported by the implementation. (See fn:round.)

17. There may be implementation-defined limits on the precision available. If the requested $precision is outside this range, it should be adjusted to the nearest value supported by the implementation. (See fn:round-half-to-even.)

18. There may be implementation-defined limits on the precision available. If the requested $precision is outside this range, it should be adjusted to the nearest value supported by the implementation. (See fn:divide-decimals.)

19. XSD 1.1 allows the string +INF as a representation of positive infinity; XSD 1.0 does not. It is implementation-defined whether XSD 1.1 is supported. (See fn:number.)

20. Any other format token, which indicates a numbering sequence in which that token represents the number 1 (one) (but see the note below). It is implementation-defined which numbering sequences, additional to those listed above, are supported. If an implementation does not support a numbering sequence represented by the given token, it must use a format token of 1. (See fn:format-integer.)

21. For all format tokens other than a digit-pattern, there may be implementation-defined lower and upper bounds on the range of numbers that can be formatted using this format token; indeed, for some numbering sequences there may be intrinsic limits. For example, the format token U+2460 (CIRCLED DIGIT ONE, ①) has a range imposed by the Unicode character repertoire — zero to 20 in Unicode versions prior to 3.2, or zero to 50 in subsequent versions. For the numbering sequences described above any upper bound imposed by the implementation must not be less than 1000 (one thousand) and any lower bound must not be greater than 1. Numbers that fall outside this range must be formatted using the format token 1. (See fn:format-integer.)

22. The set of languages for which numbering is supported is implementation-defined. If the $language argument is absent, or is set to an empty sequence, or is invalid, or is not a language supported by the implementation, then the number is formatted using the default language from the dynamic context. (See fn:format-integer.)

23. ...either a or t, to indicate alphabetic or traditional numbering respectively, the default being implementation-defined. (See fn:format-integer.)

24. The string of characters between the parentheses, if present, is used to select between other possible variations of cardinal or ordinal numbering sequences. The interpretation of this string is implementation-defined. No error occurs if the implementation does not define any interpretation for the defined string. (See fn:format-integer.)

25. It is implementation-defined what combinations of values of the format token, the language, and the cardinal/ordinal modifier are supported. If ordinal numbering is not supported for the combination of the format token, the language, and the string appearing in parentheses, the request is ignored and cardinal numbers are generated instead. (See fn:format-integer.)

26. The use of the a or t modifier disambiguates between numbering sequences that use letters. In many languages there are two commonly used numbering sequences that use letters. One numbering sequence assigns numeric values to letters in alphabetic sequence, and the other assigns numeric values to each letter in some other manner traditional in that language. In English, these would correspond to the numbering sequences specified by the format tokens a and i. In some languages, the first member of each sequence is the same, and so the format token alone would be ambiguous. In the absence of the a or t modifier, the default is implementation-defined. (See fn:format-integer.)

27. The static context provides a set of decimal formats. One of the decimal formats is unnamed, the others (if any) are identified by a QName. There is always an unnamed decimal format available, but its contents are implementation-defined. (See Defining a decimal format.)

28. IEEE states that the preferred quantum is language-defined. In this specification, it is implementation-defined. (See Trigonometric and exponential functions.)

29. IEEE defines various rounding algorithms for inexact results, and states that the choice of rounding direction, and the mechanisms for influencing this choice, are language-defined. In this specification, the rounding direction and any mechanisms for influencing it are implementation-defined. (See Trigonometric and exponential functions.)

30. The map returned by the fn:random-number-generator function may contain additional entries beyond those specified here, but it must match the record type defined above. The meaning of any additional entries is implementation-defined. To avoid conflict with any future version of this specification, the keys of any such entries should start with an underscore character. (See fn:random-number-generator.)

31. If two query parameters use the same keyword then the last one wins. If a query parameter uses a keyword or value which is not defined in this specification then the meaning is implementation-defined. If the implementation recognizes the meaning of the keyword and value then it should interpret it accordingly; if it does not recognize the keyword or value then if the fallback parameter is present with the value no it should reject the collation as unsupported, otherwise it should ignore the unrecognized parameter. (See The Unicode Collation Algorithm.)

32. The following query parameters are defined. If any parameter is absent, the default is implementation-defined except where otherwise stated. The meaning given for each parameter is non-normative; the normative specification is found in [UTS #35]. (See The Unicode Collation Algorithm.)

33. Because the set of collations that are supported is implementation-defined, an implementation has the option to support all collation URIs, in which case it will never raise this error. (See Choosing a collation.)

34. The properties available are as defined for the Unicode Collation Algorithm (see 5.3.4 The Unicode Collation Algorithm). Additional implementation-defined properties may be specified as described in the rules for UCA collation URIs. (See fn:collation.)

35. It is possible to define collations that do not have the ability to generate collation keys. Supplying such a collation will cause the function to fail. The ability to generate collation keys is an implementation-defined property of the collation. (See fn:collation-key.)

36. Conforming implementations must support normalization form NFC and may support normalization forms NFD, NFKC, NFKD, and FULLY-NORMALIZED. They may also support other normalization forms with implementation-defined semantics. (See fn:normalize-unicode.)

37. It is implementation-defined which version of Unicode (and therefore, of the normalization algorithms and their underlying data) is supported by the implementation. See [UAX #15] for details of the stability policy regarding changes to the normalization rules in future versions of Unicode. If the input string contains codepoints that are unassigned in the relevant version of Unicode, or for which no normalization rules are defined, the fn:normalize-unicode function leaves such codepoints unchanged. If the implementation supports the requested normalization form then it must be able to handle every input string without raising an error. (See fn:normalize-unicode.)

38. It is possible to define collations that do not have the ability to decompose a string into units suitable for substring matching. An argument to a function defined in this section may be a URI that identifies a collation that is able to compare two strings, but that does not have the capability to split the string into collation units. Such a collation may cause the function to fail, or to give unexpected results, or it may be rejected as an unsuitable argument. The ability to decompose strings into collation units is an implementation-defined property of the collation. The fn:collation-available function can be used to ask whether a particular collation has this property. (See Functions based on substring matching.)

39. The result of the function will always be such that validation against this schema would succeed. However, it is implementation-defined whether the result is typed or untyped, that is, whether the elements and attributes in the returned tree have type annotations that reflect the result of validating against this schema. (See fn:analyze-string.)

40. Some URI schemes are hierarchical and some are non-hierarchical. Implementations must treat the following schemes as non-hierarchical: jar, mailto, news, tag, tel, and urn. Whether additional schemes are known to be non-hierarchical implementation-defined. If a scheme is not known to be non-hierarchical, it must be treated as hierarchical. (See Parsing and building URIs.)

41. If the omit-default-ports option is true, the port is discarded and set to the empty sequence if the port number is the same as the default port for the given scheme. Implementations should recognize the default ports for http (80), https (443), ftp (21), and ssh (22). Exactly which ports are recognized is implementation-defined. (See fn:parse-uri.)

42. If the omit-default-ports option is true then the $port is set to the empty sequence if the port number is the same as the default port for the given scheme. Implementations should recognize the default ports for http (80), https (443), ftp (21), and ssh (22). Exactly which ports are recognized is implementation-defined. (See fn:build-uri.)

43. Processors may support a greater range and/or precision. The limits are implementation-defined. (See Limits and precision.)

44. Similarly, a processor may be unable accurately to represent the result of dividing a duration by 2, or multiplying a duration by 0.5. A processor that limits the precision of the seconds component of duration values must deliver a result that is as close as possible to the mathematically precise result, given these limits; if two values are equally close, the one that is chosen is implementation-defined. (See Limits and precision.)

45. All conforming processors must support year values in the range 1 to 9999, and a minimum fractional second precision of 1 millisecond or three digits (i.e., s.sss). However, processors may set larger implementation-defined limits on the maximum number of digits they support in these two situations. Processors may also choose to support the year 0 and years with negative values. The results of operations on dates that cross the year 0 are implementation-defined. (See Limits and precision.)

46. Similarly, a processor that limits the precision of the seconds component of date and time or duration values may need to deliver a rounded result for arithmetic operations. Such a processor must deliver a result that is as close as possible to the mathematically precise result, given these limits: if two values are equally close, the one that is chosen is implementation-defined. (See Limits and precision.)

47. ...the format token n, N, or Nn, indicating that the value of the component is to be output by name, in lower-case, upper-case, or title-case respectively. Components that can be output by name include (but are not limited to) months, days of the week, timezones, and eras. If the processor cannot output these components by name for the chosen calendar and language then it must use an implementation-defined fallback representation. (See The picture string.)

48. ...indicates alphabetic or traditional numbering respectively, the default being implementation-defined. This has the same meaning as in the second argument of fn:format-integer. (See The picture string.)

49. The sequence of characters in the (adjusted) first presentation modifier is reversed (for example, 999'### becomes ###'999). If the result is not a valid decimal digit pattern, then the output is implementation-defined. (See Formatting Fractional Seconds.)

50. The output for these components is entirely implementation-defined. The default presentation modifier for these components is n, indicating that they are output as names (or conventional abbreviations), and the chosen names will in many cases depend on the chosen language: see 9.8.4.8 The language, calendar, and place arguments. (See Formatting Other Components.)

51. The set of languages, calendars, and places that are supported in the date formatting functions is implementation-defined. When any of these arguments is omitted or is an empty sequence, an implementation-defined default value is used. (See The language, calendar, and place arguments.)

52. The choice of the names and abbreviations used in any given language is implementation-defined. For example, one implementation might abbreviate July as Jul while another uses Jly. In German, one implementation might represent Saturday as Samstag while another uses Sonnabend. Implementations may provide mechanisms allowing users to control such choices. (See The language, calendar, and place arguments.)

53. The choice of the names and abbreviations used in any given language for calendar units such as days of the week and months of the year is implementation-defined. (See The language, calendar, and place arguments.)

54. The calendar value if present must be a valid EQName (dynamic error: [err:FOFD1340]). If it is a lexical QName then it is expanded into an expanded QName using the statically known namespaces; if it has no prefix then it represents an expanded-QName in no namespace. If the expanded QName is in no namespace, then it must identify a calendar with a designator specified below (dynamic error: [err:FOFD1340]). If the expanded QName is in a namespace then it identifies the calendar in an implementation-defined way. (See The language, calendar, and place arguments.)

55. At least one of the above calendars must be supported. It is implementation-defined which calendars are supported. (See The language, calendar, and place arguments.)

56. The requirement to deliver a deterministic result has performance implications, and for this reason implementations may provide a user option to evaluate the function without a guarantee of determinism. The manner in which any such option is provided is implementation-defined. If the user has not selected such an option, a call of the function must either return a deterministic result or must raise a dynamic error [err:FODC0003]. (See fn:doc.)

57. Various aspects of this processing are implementation-defined. Implementations may provide external configuration options that allow any aspect of the processing to be controlled by the user. In particular:... (See fn:doc.)

58. It is implementation-defined whether DTD validation and/or schema validation is applied to the source document. (See fn:doc.)

59. The effect of a fragment identifier in the supplied URI is implementation-defined. One possible interpretation is to treat the fragment identifier as an ID attribute value, and to return a document node having the element with the selected ID value as its only child. (See fn:doc.)

60. By default, this function is deterministic. This means that repeated calls on the function with the same argument will return the same result. However, for performance reasons, implementations may provide a user option to evaluate the function without a guarantee of determinism. The manner in which any such option is provided is implementation-defined. If the user has not selected such an option, a call to this function must either return a deterministic result or must raise a dynamic error [err:FODC0003]. (See fn:collection.)

61. By default, this function is deterministic. This means that repeated calls on the function with the same argument will return the same result. However, for performance reasons, implementations may provide a user option to evaluate the function without a guarantee of determinism. The manner in which any such option is provided is implementation-defined. If the user has not selected such an option, a call to this function must either return a deterministic result or must raise a dynamic error [err:FODC0003]. (See fn:uri-collection.)

62. ...the processor may use implementation-defined heuristics to determine the likely encoding, otherwise... (See fn:unparsed-text.)

63. The fact that the resolution of URIs is defined by a mapping in the dynamic context means that in effect, various aspects of the behavior of this function are implementation-defined. Implementations may provide external configuration options that allow any aspect of the processing to be controlled by the user. In particular:... (See fn:unparsed-text.)

64. The collation used for matching names is implementation-defined, but must be the same as the collation used to ensure that the names of all environment variables are unique. (See fn:environment-variable.)

65. Except to the extent defined by these options, the precise process used to construct the XDM instance is implementation-defined. In particular, it is implementation-defined whether an XML 1.0 or XML 1.1 parser is used. (See fn:parse-xml.)

66. Except as explicitly defined, the precise process used to construct the XDM instance is implementation-defined. In particular, it is implementation-defined whether an XML 1.0 or XML 1.1 parser is used. (See fn:parse-xml-fragment.)

67. If the second argument is omitted, or is supplied in the form of an output:serialization-parameters element, then the values of any serialization parameters that are not explicitly specified is implementation-defined, and may depend on the context. (See fn:serialize.)

68. Because the [DOM: Living Standard] and [HTML: Living Standard] are not fixed, it is implementation-defined which versions are used. (See XDM Mapping from HTML DOM Nodes.)

69. If an implementation allows these nodes to be passed in via an API or similar mechanism, their behaviour is implementation-defined. (See XDM Mapping from HTML DOM Nodes.)

70. If the local name contains a character that is not a valid XML NameStartChar or NameChar, then an implementation-defined replacement string is used. The result must be a valid NCName. (See node-name Accessor.)

71. If the local name contains a character that is not a valid XML NameStartChar or NameChar, then an implementation-defined replacement string is used. The result must be a valid NCName. (See node-name Accessor.)

72. Additional implementation-defined parser options are allowed. (See HTML parser options.)

73. Any other method and html-version combinations are implementation-defined. (See fn:parse-html.)

74. The default behaviour is implementation-defined. (See fn:parse-html.)

75. An implementation-defined parsing algorithm, tree construction, and validation consistent with the specified HTML version. (See fn:parse-html.)

76. The input may contain deviations from the grammar of [RFC 7159], which are handled in an implementation-defined way. (Note: some popular extensions include allowing quotes on keys to be omitted, allowing a comma to appear after the last item in an array, allowing leading zeroes in numbers, and allowing control characters such as tab and newline to be present in unescaped form.) Since the extensions accepted are implementation-defined, an error may be raised [err:FOJS0001] if the input does not conform to the grammar. (See fn:parse-json.)

77. The supplied function is called to process the string value of any JSON number in the input. By default, numbers are processed by converting to xs:double using the XPath casting rules. Supplying the value xs:decimal#1 will instead convert to xs:decimal (which potentially retains more precision, but disallows exponential notation), while supplying a function that casts to (xs:decimal | xs:double) will treat the value as xs:decimal if there is no exponent, or as xs:double otherwise. Supplying the value fn:identity#1 causes the value to be retained unchanged as an xs:untypedAtomic. If the liberal option is false (the default), then the supplied number-parser is called if and only if the value conforms to the JSON grammar for numbers (for example, a leading plus sign and redundant leading zeroes are not allowed). If the liberal option is true then it is also called if the value conforms to an implementation-defined extension of this grammar. (See fn:parse-json.)

78. The input may contain deviations from the grammar of [RFC 7159], which are handled in an implementation-defined way. (Note: some popular extensions include allowing quotes on keys to be omitted, allowing a comma to appear after the last item in an array, allowing leading zeroes in numbers, and allowing control characters such as tab and newline to be present in unescaped form.) Since the extensions accepted are implementation-defined, an error may be raised (see below) if the input does not conform to the grammar. (See fn:json-to-xml.)

79. Default: Implementation-defined. (See fn:json-to-xml.)

80. Indicates that the resulting XDM instance must be typed; that is, the element and attribute nodes must carry the type annotations that result from validation against the schema given at C.2 Schema for the result of fn:json-to-xml, or against an implementation-defined schema if the liberal option has the value true. (See fn:json-to-xml.)

81. The result of the function will always be such that validation against this schema would succeed. However, it is implementation-defined whether the result is typed or untyped, that is, whether the elements and attributes in the returned tree have type annotations that reflect the result of validating against this schema. (See fn:csv-to-xml.)

82. Additional, implementation-defined options may be available, for example, to control aspects of the XML serialization, to specify the grammar start symbol, or to produce output formats other than XML. (See fn:invisible-xml.)

83. If the arguments to fn:function-lookup identify a function that is present in the static context of the function call, the function will always return the same function that a static reference to this function would bind to. If there is no such function in the static context, then the results depend on what is present in the dynamic context, which is implementation-defined. (See fn:function-lookup.)

84. Default: The version given in the prolog of the library module; or implementation-defined if this is absent. (See fn:load-xquery-module.)

85. A sequence of URIs (in the form of xs:string values) which may be used or ignored in an implementation-defined way.... (See fn:load-xquery-module.)

86. Values for vendor-defined configuration options for the XQuery processor used to process the request. The key is the name of an option, expressed as a QName: the namespace URI of the QName should be a URI controlled by the vendor of the XQuery processor. The meaning of the associated value is implementation-defined. Implementations should ignore options whose names are in an unrecognized namespace. The option parameter conventions do not apply to this contained map.... (See fn:load-xquery-module.)

87. It is implementation-defined whether constructs in the library module are evaluated in the same execution scope as the calling module. (See fn:load-xquery-module.)

88. The library module that is loaded may import schema declarations using an import schema declaration. It is implementation-defined whether schema components in the in-scope schema definitions of the calling module are automatically added to the in-scope schema definitions of the dynamically loaded module. The in-scope schema definitions of the calling and called modules must be consistent, according to the rules defined in Section 2.2.5 Consistency Constraints ^XQ31. (See fn:load-xquery-module.)

89. Default: Implementation-defined. (See fn:transform.)

90. Default: Implementation-defined. (See fn:transform.)

91. If the implementation provides a way of writing or invoking functions with side-effects, this post-processing function might be used to save a copy of the result document to persistent storage. For example, if the implementation provides access to the EXPath File library [EXPath], then a serialized document might be written to filestore by calling the file:write function. Similar mechanisms might be used to issue an HTTP POST request that posts the result to an HTTP server, or to send the document to an email recipient. The semantics of calling functions with side-effects are entirely implementation-defined. (See fn:transform.)

92. Calls to fn:transform can potentially have side-effects even in the absence of the post-processing option, because the XSLT specification allows a stylesheet to invoke extension functions that have side-effects. The semantics in this case are implementation-defined. (See fn:transform.)

93. A string intended to be used as the static base URI of the principal stylesheet module. This value must be used if no other static base URI is available. If the supplied stylesheet already has a base URI (which will generally be the case if the stylesheet is supplied using stylesheet-node or stylesheet-location) then it is implementation-defined whether this parameter has any effect. If the value is a relative reference, it is resolved against the static base URI of the fn:transform function call.... (See fn:transform.)

94. Values for vendor-defined configuration options for the XSLT processor used to process the request. The key is the name of an option, expressed as a QName: the namespace URI of the QName should be a URI controlled by the vendor of the XSLT processor. The meaning of the associated value is implementation-defined. Implementations should ignore options whose names are in an unrecognized namespace. Default is an empty map.... (See fn:transform.)

95. It is implementation-defined whether the XSLT transformation is executed within the same execution scope as the calling code. (See fn:transform.)

96. XSLT 1.0 does not define any error codes, so this is the likely outcome with an XSLT 1.0 processor. XSLT 2.0 and 3.0 do define error codes, but some APIs do not expose them. If multiple errors are signaled by the transformation (which is most likely to happen with static errors) then the error code should where possible be that of one of these errors, chosen arbitrarily; the processor may make details of additional errors available to the application in an implementation-defined way. (See fn:transform.)

97. The key of the combined entry is taken from one of the duplicate entries: it is implementation-defined which one is used. (It is possible for two keys to be considered duplicates even if they differ: for example, they may have different type annotations, or they may be xs:dateTime values with different timezones.) ... (See map:build.)

98. The key of the combined entry is one of the duplicate keys: which one is chosen is implementation-defined. (Two keys that are deemed duplicates may differ: for example they may have different type annotations, or they may be xs:dateTime values with different timezones.)... (See map:merge.)

99. Equivalent to specifying "combine": fn(){error(xs:QName("err:FOJS0003"), ...) (the remaining arguments to fn:error being implementation-defined). (See map:merge.)

100. Equivalent to specifying "combine": fn($a, $b){ one-of($a, $b) } where one-of chooses either $a or $b in an implementation-defined way. (See map:merge.)

101. If ST is xs:float or xs:double, then TV is the xs:decimal value, within the set of xs:decimal values that the implementation is capable of representing, that is numerically closest to SV. If two values are equally close, then the one that is closest to zero is chosen. If SV is too large to be accommodated as an xs:decimal, (see [XML Schema Part 2: Datatypes Second Edition] for implementation-defined limits on numeric values) a dynamic error is raised [err:FOCA0001]. If SV is one of the special xs:float or xs:double values NaN, INF, or -INF, a dynamic error is raised [err:FOCA0002]. (See Casting to xs:decimal.)

102. In casting to xs:decimal or to a type derived from xs:decimal, if the value is not too large or too small but nevertheless cannot be represented accurately with the number of decimal digits available to the implementation, the implementation may round to the nearest representable value or may raise a dynamic error [err:FOCA0006]. The choice of rounding algorithm and the choice between rounding and error behavior is implementation-defined. (See Casting from xs:string and xs:untypedAtomic.)

103. If ST is xs:decimal, xs:float or xs:double, then TV is SV with the fractional part discarded and the value converted to xs:integer. Thus, casting 3.1456 returns 3 while -17.89 returns -17. Casting 3.124E1 returns 31. If SV is too large to be accommodated as an integer, (see [XML Schema Part 2: Datatypes Second Edition] for implementation-defined limits on numeric values) a dynamic error is raised [err:FOCA0003]. If SV is one of the special xs:float or xs:double values NaN, INF, or -INF, a dynamic error is raised [err:FOCA0002]. (See Casting to xs:integer.)

104. The tz timezone database, available at http://www.iana.org/time-zones. It is implementation-defined which version of the database is used. (See IANA Timezone Database.)

105. Unicode Standard Annex #15: Unicode Normalization Forms. Ed. Mark Davis and Ken Whistler, Unicode Consortium. The current version is 9.0.0, dated 2016-02-24. As with [The Unicode Standard], the version to be used is implementation-defined. Available at: http://www.unicode.org/reports/tr15/. (See UAX #15.)

106. Unicode Standard Annex #29: Unicode Text Segmentation. Ed. Josh Hadley, Unicode Consortium. The current version is 15.1.0, dated 2023-08-16. As with [The Unicode Standard], the version to be used is implementation-defined. Available at: http://www.unicode.org/reports/tr29/. (See UAX #29.)

107. The Unicode Consortium, Reading, MA, Addison-Wesley, 2016. The Unicode Standard as updated from time to time by the publication of new versions. See http://www.unicode.org/standard/versions/ for the latest version and additional information on versions of the standard and of the Unicode Character Database. The version of Unicode to be used is implementation-defined, but implementations are recommended to use the latest Unicode version; currently, Version 9.0.0. (See The Unicode Standard.)

108. Unicode Technical Standard #10: Unicode Collation Algorithm. Ed. Mark Davis and Ken Whistler, Unicode Consortium. The current version is 9.0.0, dated 2016-05-18. As with [The Unicode Standard], the version to be used is implementation-defined. Available at: http://www.unicode.org/reports/tr10/. (See UTS #10.)

109. Unicode Technical Standard #35: Unicode Locale Data Markup Language. Ed Mark Davis et al, Unicode Consortium. The current version is 29, dated 2016-03-15. As with [The Unicode Standard], the version to be used is implementation-defined. Available at: http://www.unicode.org/reports/tr35/. (See UTS #35.)

G Changes since version 3.1 (Non-Normative)

H Compatibility with Previous VersionsBackward compatibility (Non-Normative)

This section summarizes the extent to which this specification is compatible with previous versions.

Version 4.0 of this function library is fully backwards compatible with version 3.1, except as noted below:

1. In fn:deep-equal, and in other functions such as fn:distinct-values that refer to fn:deep-equal, the rules for comparing values of different numeric types (for example, xs:double and xs:decimal) have changed. In previous versions of the specification, xs:decimal values were converted to xs:double, leading to a possible loss of precision. This could make comparisons non-transitive, leading to problems when grouping, and potentially (depending on the sort algorithm) with sorting. The problem has been fixed by requiring comparisons to be performed based on the exact mathematical value without any loss of precision.

   This means, for example, that deep-equal(0.2, 0.2e0) is now false, whereas in previous versions it was true. The two values are not mathematically equal, because the exact decimal equivalent of the xs:double value written as 0.2e0 is 0.200000000000000011102230246251565404236316680908203125.

   The corresponding change has not been made to the = and eq operators, because it was found to be too disruptive. For example, if the context node is the element <e price="10.0" discount="0.2"/>, there is an expectation that the expression @price - @discount = 9.8 should return true. But (assuming untyped data), the result of the subtraction is an xs:double whose precise value is 9.800000000000000710542735760100185871124267578125, so comparing the two values as decimals would return false.

2. In previous versions, unrecognized options supplied to the $options parameter of functions such as fn:parse-json were silently ignored. In 4.0, they are rejected as a type error, unless they are QNames with a non-absent namespace, or are extensions recognized by the implementation.

3. In version 4.0, omitting the $value of fn:error has the same effect as setting it to an empty sequence. In 3.1, the effects could be different (the effect of omitting the argument was implementation-defined).

4. In version 3.1, the fn:deep-equal function did not merge adjacent text nodes after stripping comments and processing instructions, so the elements <a>abc<!--note1-->def</code> and <a>abcde<!--note2-->f</code> were considered non-equal. In version 4.0, the text nodes are now merged prior to comparison, so these two elements compare equal.

5. The format of numeric values in the output of fn:xml-to-json may be different. In version 3.1, the supplied value was parsed as an xs:double and then serialized using the casting rules, resulting in an input value of 10000000 being output as 1e7. In version 4.0, the value is output as is, except for any changes (such as stripping of leading zeroes or a leading plus sign) that might be needed to ensure the result is valid JSON.

6. In version 4.0, the function signature of fn:namespace-uri-for-prefix constrains the first argument to be either an xs:NCName or a zero-length string (the new coercion rules mean that any string in the form of an xs:NCName is acceptable). If a string is supplied that does not meet these requirements, a type error will be raised. In version 3.1, this was not an error: it came under the rule that when no namespace binding existed for the supplied prefix, the function would return an empty sequence.

   Furthermore, because the expected type of this parameter is no longer xs:string, the special coercion rules for xs:string parameters in XPath 1.0 compatibility mode no longer apply. For example, supplying xs:duration('PT1H') as the first argument will now raise a type error, rather than looking for a namespace binding for the prefix PT1H.

7. Version 4.0 makes it clear that the casting of a value other than xs:string or xs:untypedAtomic to a list type (whether using a cast expression or a constructor function) is a type error [err:XPTY0004]^XP. Previously this was defined as an error, but the kind of error and the error code were left unspecified. Accordingly, the function signatures of the constructor functions for built-in list types have been changed to use an argument type of xs:string?.

8. The way that fn:min and fn:max compare numeric values of different types has changed. The most noticeable effect is that when these functions are applied to a sequence of xs:integer or xs:decimal values, the result is an xs:integer or xs:decimal, rather than the result of converting this to an xs:double.

9. The type of the third argument of fn:format-number has changed from xs:string to (xs:string | xs:QName). Because the expected type of this parameter is no longer xs:string, the special coercion rules for xs:string parameters no longer apply. For example, it is no longer possible to supply an instance of xs:anyURI or (when XPath 1.0 compatibility mode is in force) an instance of xs:boolean or xs:duration.

For compatibility issues regarding earlier versions, see the 3.1 version of this specification.