2.1.1 The is-card-number() Function

boolean is-card-number(string?)

If the string parameter conforms to the pattern restriction of zero or more numeric digits, then this function applies the algorithm described in [Luhn Patent] and returns true if the string is empty or if the number in the string satisfies the Luhn formula. Otherwise, false is returned. If the parameter is omitted, it defaults to the string-value of the current context node.

Examples:

is-card-number(.)

is-card-number('4111111111111111')

is-card-number('123')

2.1.2 The digest() Function

string digest(string, string, string?)

This function accepts a string of data, a string indicating a cryptographic hashing algorithm, and an optional string indicating an encoding method. The data string is serialized as UTF-8, the hash value is then computed using the indicated hash algorithm, and the hash value is then encoded by the indicated method, and the result is returned by the function. The following table presents the keywords for the second string parameter and the corresponding hash algorithms:

This recommendation defines the values hex and base64 for the third string parameter that indicates the encoding method. If the parameter is missing, then the default is base64. The hex and base64 encoding methods of this function correspond to the encodings defined in [XML Schema part 2] for the datatypes hexBinary and base64Binary, respectively. Any other string value given for the encoding method is unsupported.

digest('abc', 'SHA-1', 'hex')

digest('abc', 'MD5', 'hex')

digest('abc', 'SHA-256', 'hex')

2.1.3 The hmac() Function

string hmac(string, string, string, string?)

This function accepts a string for a key or shared secret, a string of data, a string indicating a cryptographic hashing algorithm, and an optional string indicating an encoding method. The key and data strings are serialized as UTF-8, and they are subjected to the HMAC algorithm defined in [HMAC] and parameterized by the the hash algorithm indicated by the third parameter. The result is encoded with the method indicated by the fourth parameter, and the result is returned by the function.

The following table presents the keywords for the third string parameter and the corresponding hash algorithms:

This recommendation defines the values hex and base64 for the fourth string parameter that indicates the encoding method. If the parameter is missing, then the default is base64. The hex and base64 encoding methods of this function correspond to the encodings defined in [XML Schema part 2] for the datatypes hexBinary and base64Binary, respectively. Any other string value given for the encoding method is unsupported.

hmac('Jefe', 'what do ya want for nothing?', 'SHA-1', 'hex')

hmac('Jefe', 'what do ya want for nothing?', 'MD5', 'hex')

hmac('Jefe', 'what do ya want for nothing?', 'SHA-256', 'hex')

2.2.1 The local-date() Function

string local-date()

This function returns a lexical xsd:date obtained as if by the following rules: the result of now() is converted to a local date based on the user agent time zone information. If no time zone information is available, then the date portion of the result of now() is returned.

Example:

local-date()

substring(local-date(), 1, 10)

days-to-date(days-from-date(local-date()) + 31) 

2.2.2 The local-dateTime() Function

string local-dateTime()

This function returns a lexical xsd:dateTime obtained as if by the following rules: the result of now() is converted to a local dateTime based on the user agent time zone information. If no time zone information is available, then the result of now() is returned.

Example:

local-dateTime()

adjust-dateTime-to-timezone(seconds-to-dateTime(seconds-from-dateTime(local-dateTime()) + 7200))

2.2.3 The now() Function

string now()

The now function returns the current UTC date and time as a string value in the canonical XML Schema xsd:dateTime format. If time zone information is available, it is used to convert the date and time to UTC. If no time zone information is available, then the date and time are assumed to be in UTC.

now()

seconds-to-dateTime(seconds-from-dateTime(now()) + 7200)

2.2.4 The days-from-date() Function

number days-from-date(string)

This function returns a whole number of days, according to the following rules:

If the string parameter represents a legal lexical xsd:date or xsd:dateTime, the return value is equal to the number of days difference between the specified date or dateTime (normalized to UTC) and 1970-01-01. Hour, minute, and second components are ignored after normalization. Any other input parameter causes a return value of NaN.

Examples:

days-from-date("2002-01-01")

days-from-date("2002-01-01-07:00")

days-from-date("1969-12-31")

2.2.5 The days-to-date() Function

string days-to-date(number)

This function returns a string containing a lexical xsd:date that corresponds to the number of days passed as the parameter according to the following rules:

The number parameter is rounded to the nearest whole number, and the result is interpreted as the difference between the desired date and 1970-01-01. An input parameter value of NaN results in output of the empty string.

Examples:

days-to-date(11688)

days-to-date(-1)

2.2.6 The seconds-from-dateTime() Function

number seconds-from-dateTime(string)

This function returns a possibly fractional number of seconds, according to the following rules:

If the string parameter represents a legal lexical xsd:dateTime, the return value is equal to the number of seconds difference between the specified dateTime (normalized to UTC) and 1970-01-01T00:00:00Z. If no time zone is specified, UTC is used. Any other input string parameter causes a return value of NaN. This function does not support leap seconds.

Example:

seconds-from-dateTime('1970-01-01T00:00:00Z')

seconds-from-dateTime('1970-01-01T00:00:00-08:00')

seconds-from-dateTime('1970-01-02T00:00:00Z')

seconds-from-dateTime('1969-12-31T00:00:00Z')

2.2.7 The seconds-to-dateTime() Function

string seconds-to-dateTime(number)

This function returns a string containing a lexical xsd:dateTime that corresponds to the number of seconds passed as the parameter according to the following rules:

The number parameter is rounded to the nearest whole number, and the result is interpreted as the difference between the desired UTC dateTime and 1970-01-01T00:00:00Z. An input parameter value of NaN results in output of the empty string. This function does not support leap seconds.

Examples:

seconds-to-dateTime(0)

seconds-from-dateTime(28800)

seconds-to-dateTime(seconds-from-dateTime(now()) + 7200)

adjust-dateTime-to-timezone(seconds-to-dateTime(seconds-from-dateTime(now()) + 7200))

2.2.8 The adjust-dateTime-to-timezone() Function

string adjust-dateTime-to-timezone(string)

This function adjusts a legal lexical xsd:dateTime received as the string parameter to the local time zone of the implementation, and returns the result. If the string argument contains no time zone, then the result is the string argument with the local time zone as the time zone component. If the implementation does not have access to time zone information, UTC is used. The result is empty string if the string argument is the empty sequence or not a legal lexical xsd:dateTime.

Examples:

adjust-dateTime-to-timezone('2007-10-07T02:22:00')

adjust-dateTime-to-timezone('2007-10-02T21:26:43Z')

adjust-dateTime-to-timezone(seconds-to-dateTime(seconds-from-dateTime(now()) + 7200))

2.2.9 The seconds() Function

number seconds(string)

This function returns a possibly fractional number of seconds, according to the following rules:

If the string parameter represents a legal lexical xsd:duration, the return value is equal to the number specified in the seconds component plus 60 * the number specified in the minutes component, plus 60 * 60 * the number specified in the hours component, plus 60 * 60 * 24 * the number specified in the days component. The sign of the result will match the sign of the duration. Year and month components, if present, are ignored. Any other input parameter causes a return value of NaN.

seconds("P3DT10H30M1.5S")

seconds("P1Y2M")

seconds("3")

2.2.10 The months() Function

number months(string)

This function returns a whole number of months, according to the following rules:

If the string parameter represents a legal lexical xsd:duration, the return value is equal to the number specified in the months component plus 12 * the number specified in the years component. The sign of the result will match the sign of the duration. Day, hour, minute, and second components, if present, are ignored. Any other input parameter causes a return value of NaN.

months("P1Y2M")

months("-P19M")

2.3.1 The if() Function

string if(boolean, string, string)

Function if evaluates the first parameter as boolean, returning the second parameter when true, otherwise the third parameter.

2.3.2 The choose() Function

object choose(boolean, object, object)

This function provides a conditional test that chooses an object to return based on the boolean parameter. If the boolean parameter is true, then the first object is returned, otherwise the second object is returned. Each of the object parameters can be of any XPath datatype as described in [XPath 1.0], and this function does no type conversion of the parameter it chooses to return.

Example:

choose(count(x) > 0, x, y)

choose(@x, @x, 0)

2.3.3 The compare() Function

number compare(string, string)

This function returns -1, 0, or 1, depending on whether the value of the first argument is respectively less than, equal to, or greater than the value of second argument based on lexicographic comparison using Unicode code point values [Unicode Collation Algorithm].

Example:

compare('apples', 'oranges')

2.3.4 The count-non-empty() Function

number count-non-empty(node-set)

Function count-non-empty returns the number of non-empty nodes in argument node-set. A node is considered non-empty if it is convertible into a string with a greater-than zero length.

Example:

choose(count-non-empty(x) > 0, x, y)

2.3.5 The boolean-from-string() Function

boolean boolean-from-string(string)

Function boolean-from-string returns true if the required parameter string is "true" or "1", or false if parameter string is "false", or "0". This is useful when referencing a Schema xsd:boolean datatype in an XPath expression. If the parameter string matches none of the above strings, according to a case-insensitive comparison, the return value is false.

Example:

choose(boolean-from-string(isMinor), parentApplicant, primaryApplicant)

2.3.6 The current() Function

node-set current()

Returns the context node used to initialize the evaluation of the containing XPath expression.

Example:

<data xmlns="">
	<converter>
		<amount>100</amount>
		<currency>jpy</currency>
	</converter>

	<convTable date="20040212" currency="cdn">
		<rate currency="eur">0.59376</rate>
		<rate currency="mxn">8.37597</rate>
		<rate currency="jpy">80.23451</rate>
		<rate currency="usd">0.76138</rate>
	</convTable>
</data>	

converter/amount * convTable/rate[@currency = current()/converter/currency]

2.4.1 The avg() Function

number avg(node-set)

Function avg returns the arithmetic average of the result of converting the string-values of each node in the argument node-set to a number. The sum is computed with sum(), and divided with div by the value computed with count(). If the parameter is an empty node-set, or if any of the nodes evaluate to NaN, the return value is NaN.

2.4.2 The min() Function

number min(node-set)

Function min returns the minimum value of the result of converting the string-values of each node in argument node-set to a number. "Minimum" is determined with the < operator. If the parameter is an empty node-set, or if any of the nodes evaluate to NaN, the return value is NaN.

2.4.3 The max() Function

number max(node-set)

Function max returns the maximum value of the result of converting the string-values of each node in argument node-set to a number. "Maximum" is determined with the < operator. If the parameter is an empty node-set, or if any of the nodes evaluate to NaN, the return value is NaN.

2.4.4 The power() Function

number power(number, number)

Raises the first argument to the power of the second argument, returning the result. If the calculation does not result in a real number, then NaN is returned.

Examples:

power(2, 3)

power(-1, 0.5)

if (prin>0 and dur>0 and rate>0, prin*rate/(1-power(1+rate, -dur)), 0)

2.4.5 The random() Function

number random(boolean?)

This function generates and returns a uniformly distributed random or pseudorandom number in the range from 0.0 up to but excluding 1.0. This function accepts an optional boolean parameter that is false by default. If true, the random number generator for this function is first seeded with a source of randomness before generating the return value. A typical implementation may seed the random number generator with the current system time in milliseconds when random(true) is invoked, and it may apply a linear congruential formula to generate return values on successive invocations of the function.

Example:

random()