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Proposed List of Functions and Operators

The following functions and operators (and their short descriptions) are taken from XQuery 1.0 and XPath 2.0 Functions and Operators (W3C Recommendation 23 January 2007). It is intended to be a starting point for discussions on the RIF Core builtins.

Functions and Operators on Numerics

The following functions and operators are defined on the numeric datatypes defined in XML Schema Part 2: Datatypes Second Edition.

Operators on Numeric Values

1. op:numeric-add 

op:numeric-add($arg1 as numeric, $arg2 as numeric) as numeric

2. op:numeric-subtract 

op:numeric-subtract($arg1 as numeric, $arg2 as numeric) as numeric

3. op:numeric-multiply 

op:numeric-multiply($arg1 as numeric, $arg2 as numeric) as numeric

4. op:numeric-divide 

op:numeric-divide($arg1 as numeric, $arg2 as numeric) as numeric

Comparison Operators on Numeric Values

1. op:numeric-equal 

op:numeric-equal($arg1 as numeric, $arg2 as numeric) as xs:boolean

2. op:numeric-less-than 

op:numeric-less-than($arg1 as numeric, $arg2 as numeric) as xs:boolean

3. op:numeric-greater-than 

op:numeric-greater-than($arg1 as numeric, $arg2 as numeric) as xs:boolean

Functions on Strings

The functions and operators are defined on the XML Schema Part 2: Datatypes Second Edition xs:string datatype and the datatypes derived from it.

Equality and Comparison of Strings

1. fn:compare 

fn:compare($comparand1 as xs:string?, 
           $comparand2 as xs:string?) as xs:integer?

fn:compare($comparand1   as xs:string?,
           $comparand2   as xs:string?,
           $collation    as xs:string) as xs:integer?

Returns -1, 0, or 1, depending on whether the value of the $comparand1 is respectively less than, equal to, or greater than the value of $comparand2, according to the rules of the collation that is used.

Functions on String Values

1. fn:concat 

fn:concat($arg1  as xs:anyAtomicType?,
          $arg2  as xs:anyAtomicType?,
          ...  ) as xs:string

Accepts two or more xs:anyAtomicType arguments and casts them to xs:string. Returns the xs:string that is the concatenation of the values of its arguments after conversion.

2. fn:string-join 

fn:string-join($arg1 as xs:string*, $arg2 as xs:string) as xs:string

Returns a xs:string created by concatenating the members of the $arg1 sequence using $arg2 as a separator.

3. fn:substring 

fn:substring( $sourceString      as xs:string?,
              $startingLoc       as xs:double) as xs:string

fn:substring( $sourceString      as xs:string?,
              $startingLoc       as xs:double,
              $length            as xs:double) as xs:string

Returns the portion of the value of $sourceString beginning at the position indicated by the value of $startingLoc and continuing for the number of characters indicated by the value of $length. The characters returned do not extend beyond $sourceString. If $startingLoc is zero or negative, only those characters in positions greater than zero are returned.

4. fn:string-length 

fn:string-length() as xs:integer

fn:string-length($arg as xs:string?) as xs:integer

Returns an xs:integer equal to the length in characters of the value of $arg.

5. fn:upper-case 

fn:upper-case($arg as xs:string?) as xs:string

6. fn:lower-case 

fn:lower-case($arg as xs:string?) as xs:string

7. fn:encode-for-uri 

fn:encode-for-uri($uri-part as xs:string?) as xs:string

This function encodes reserved characters in an xs:string that is intended to be used in the path segment of a URI. It is invertible but not idempotent.

8. fn:iri-to-uri 

fn:iri-to-uri($iri as xs:string?) as xs:string

9. fn:escape-html-uri 

fn:escape-html-uri($uri as xs:string?) as xs:string

This function escapes all characters except printable characters of the US-ASCII coded character set, specifically the octets ranging from 32 to 126 (decimal). The effect of the function is to escape a URI in the manner html user agents handle attribute values that expect URIs. Each character in $uri to be escaped is replaced by an escape sequence, which is formed by encoding the character as a sequence of octets in UTF-8, and then representing each of these octets in the form %HH, where HH is the hexadecimal representation of the octet. This function must always generate hexadecimal values using the upper-case letters A-F.

Functions Based on Substring Matching

The functions described here examine a string $arg1 to see whether it contains another string $arg2 as a substring. The result depends on whether $arg2 is a substring of $arg1, and if so, on the range of characters in $arg1 which $arg2 matches.

1. fn:contains 

fn:contains($arg1 as xs:string?, $arg2 as xs:string?) as xs:boolean

fn:contains( $arg1      as xs:string?,
             $arg2      as xs:string?,
             $collation as xs:string) as xs:boolean

Returns an xs:boolean indicating whether or not the value of $arg1 contains (at the beginning, at the end, or anywhere within) at least one sequence of collation units that provides a minimal match to the collation units in the value of $arg2, according to the collation that is used. "Minimal match" is defined in Unicode Collation Algorithm.

2. fn:starts-with 

fn:starts-with($arg1 as xs:string?, $arg2 as xs:string?) as xs:boolean

fn:starts-with( $arg1      as xs:string?,
                $arg2      as xs:string?,
                $collation as xs:string) as xs:boolean

Returns an xs:boolean indicating whether or not the value of $arg1 starts with a sequence of collation units that provides a minimal match to the collation units of $arg2 according to the collation that is used. "Minimal match" is defined in Unicode Collation Algorithm.

3. fn:ends-with 

fn:ends-with($arg1 as xs:string?, $arg2 as xs:string?) as xs:boolean

fn:ends-with( $arg1      as xs:string?,
              $arg2      as xs:string?,
              $collation as xs:string) as xs:boolean

4. fn:substring-before 

fn:substring-before($arg1 as xs:string?, $arg2 as xs:string?) as xs:string

fn:substring-before( $arg1       as xs:string?,
                     $arg2       as xs:string?,
                     $collation  as xs:string) as xs:string

Returns the substring of the value of $arg1 that precedes in the value of $arg1 the first occurrence of a sequence of collation units that provides a minimal match to the collation units of $arg2 according to the collation that is used.

5. fn:substring-after 

fn:substring-after($arg1 as xs:string?, $arg2 as xs:string?) as xs:string

fn:substring-after( $arg1        as xs:string?,
                    $arg2        as xs:string?,
                    $collation   as xs:string) as xs:string

String Functions that Use Pattern Matching

The three functions described here make use of a regular expression syntax for pattern matching. The regular expression syntax is described here.

1. fn:matches 

fn:matches($input as xs:string?, $pattern as xs:string) as xs:boolean

fn:matches( $input       as xs:string?,
            $pattern     as xs:string,
            $flags       as xs:string) as xs:boolean

The function returns true if $input matches the regular expression supplied as $pattern as influenced by the value of $flags, if present; otherwise, it returns false.

The effect of calling the first version of this function (omitting the argument $flags) is the same as the effect of calling the second version with the $flags argument set to a zero-length string. Flags are defined in 7.6.1.1 Flags.

2. fn:replace 

fn:replace( $input       as xs:string?,
            $pattern     as xs:string,
            $replacement as xs:string) as xs:string

fn:replace( $input       as xs:string?,
            $pattern     as xs:string,
            $replacement as xs:string,
            $flags       as xs:string) as xs:string

The function returns the xs:string that is obtained by replacing each non-overlapping substring of $input that matches the given $pattern with an occurrence of the $replacement string.

3. fn:tokenize 

fn:tokenize($input as xs:string?, $pattern as xs:string) as xs:string*

fn:tokenize( $input      as xs:string?,
             $pattern    as xs:string,
             $flags      as xs:string) as xs:string*

This function breaks the $input string into a sequence of strings, treating any substring that matches $pattern as a separator. The separators themselves are not returned.

Functions and Operators on Dates and Times

Date/time datatype values

As defined in Section 3.3.2 Dates and Times, xs:dateTime, xs:date, xs:time, xs:gYearMonth, xs:gYear, xs:gMonthDay, xs:gMonth, xs:gDay values, referred to collectively as date/time values, are represented as seven components or properties: year, month, day, hour, minute, second and timezone. The value of the first five components are xs:integers. The value of the second component is an xs:decimal and the value of the timezone component is an xs:dayTimeDuration. For all the date/time datatypes, the timezone property is optional and may or may not be present. Depending on the datatype, some of the remaining six properties must be present and some must be absent. Absent, or missing, properties are represented by the empty sequence. This value is referred to as the local value in that the value is in the given timezone. Before comparing or subtracting xs:dateTime values, this local value must be translated or normalized to UTC.

MK: what about time arithmetics?

Comparison Operators on Date and Time Values

1. op:dateTime-equal 

op:dateTime-equal($arg1 as xs:dateTime, $arg2 as xs:dateTime) as xs:boolean

Returns true if and only if the value of $arg1 is equal to the value of $arg2 according to the algorithm defined in section 3.2.7.4 of XML Schema Part 2: Datatypes Second Edition "Order relation on dateTime" for xs:dateTime values with timezones. Returns false otherwise.

2. op:dateTime-less-than 

op:dateTime-less-than($arg1 as xs:dateTime, $arg2 as xs:dateTime) as xs:boolean

3. op:dateTime-greater-than 

op:dateTime-greater-than( $arg1  as xs:dateTime,
                          $arg2  as xs:dateTime) as xs:boolean

4. op:date-equal 

op:date-equal($arg1 as xs:date, $arg2 as xs:date) as xs:boolean

Returns true if and only if the starting instant of $arg1 is equal to starting instant of $arg2. Returns false otherwise. The starting instant of an xs:date is the xs:dateTime at time 00:00:00 on that date.

5. op:date-less-than 

op:date-less-than($arg1 as xs:date, $arg2 as xs:date) as xs:boolean

6. op:date-greater-than 

op:date-greater-than($arg1 as xs:date, $arg2 as xs:date) as xs:boolean

Component Extraction Functions on Dates and Times

1. fn:year-from-dateTime 

fn:year-from-dateTime($arg as xs:dateTime?) as xs:integer?

Returns an xs:integer representing the year component in the localized value of $arg. The result may be negative.

2. fn:month-from-dateTime 

fn:month-from-dateTime($arg as xs:dateTime?) as xs:integer?

3. fn:day-from-dateTime 

fn:day-from-dateTime($arg as xs:dateTime?) as xs:integer?

4. fn:hours-from-dateTime 

fn:hours-from-dateTime($arg as xs:dateTime?) as xs:integer?

5. fn:minutes-from-dateTime 

fn:minutes-from-dateTime($arg as xs:dateTime?) as xs:integer?

6. fn:seconds-from-dateTime 

fn:seconds-from-dateTime($arg as xs:dateTime?) as xs:decimal?

7. fn:timezone-from-dateTime 

fn:timezone-from-dateTime($arg as xs:dateTime?) as xs:dayTimeDuration?

Returns the timezone component of $arg if any. If $arg has a timezone component, then the result is an xs:dayTimeDuration that indicates deviation from UTC; its value may range from +14:00 to -14:00 hours, both inclusive. Otherwise, the result is the empty sequence.

8. fn:year-from-date 

fn:year-from-date($arg as xs:date?) as xs:integer?

9. fn:month-from-date 

fn:month-from-date($arg as xs:date?) as xs:integer?

10. fn:day-from-date 

fn:day-from-date($arg as xs:date?) as xs:integer?

11. fn:timezone-from-date 

fn:timezone-from-date($arg as xs:date?) as xs:dayTimeDuration?

12. fn:hours-from-time 

fn:hours-from-time($arg as xs:time?) as xs:integer?

13. fn:minutes-from-time 

fn:minutes-from-time($arg as xs:time?) as xs:integer?

14. fn:seconds-from-time 

fn:seconds-from-time($arg as xs:time?) as xs:decimal?

15. fn:timezone-from-time 

fn:timezone-from-time($arg as xs:time?) as xs:dayTimeDuration?

Timezone Adjustment Functions on Dates and Time Values

1. fn:adjust-dateTime-to-timezone 

fn:adjust-dateTime-to-timezone($arg as xs:dateTime?) as xs:dateTime?

fn:adjust-dateTime-to-timezone( $arg      as xs:dateTime?,
                                $timezone as xs:dayTimeDuration?) as xs:dateTime?

Adjusts an xs:dateTime value to a specific timezone, or to no timezone at all. If $timezone is the empty sequence, returns an xs:dateTime without a timezone. Otherwise, returns an xs:dateTime with a timezone.

2. fn:adjust-date-to-timezone 

fn:adjust-date-to-timezone($arg as xs:date?) as xs:date?

fn:adjust-date-to-timezone( $arg         as xs:date?,
                            $timezone    as xs:dayTimeDuration?) as xs:date?

Adjusts an xs:date value to a specific timezone, or to no timezone at all. If $timezone is the empty sequence, returns an xs:date without a timezone. Otherwise, returns an xs:date with a timezone. For purposes of timezone adjustment, an xs:date is treated as an xs:dateTime with time 00:00:00.

3. fn:adjust-time-to-timezone 

fn:adjust-time-to-timezone($arg as xs:time?) as xs:time?

fn:adjust-time-to-timezone( $arg         as xs:time?,
                            $timezone    as xs:dayTimeDuration?) as xs:time?

Adjusts an xs:time value to a specific timezone, or to no timezone at all. If $timezone is the empty sequence, returns an xs:time without a timezone. Otherwise, returns an xs:time with a timezone.