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Functions and Expressions
Use HCL Link functions and expressions to create component rules and map rules.
XML functions
There are several XML functions that you can call from component rules and map rules to process input XML data.
XPATHEX
The XPATHEX function queries the XML input by using the XMLLIB library, and logs function processing in the directory where the map runs.

Functions and Expressions
Use HCL Link functions and expressions to create component rules and map rules.
- Expressions and evaluations
  The documentation provided here describes HCL Link functions and expressions. Functions and expressions are used to create component rules and map rules.
- Using functions
  A function is an expression that generates an output by performing a certain operation on one or more inputs.
- Syntax of a function
  The following is an example of a function:
- Function argument syntax
  Arguments typically have some restrictions on the expression used for that argument.
- Character-set encoding functions
  Functions that use the HCL Link EXIT architecture convert data to the native character set of the platform as part of the function call.
- General functions
  There are several general functions you can call from map rule to process input.
- Bidirectional functions
  Bidirectional languages such as Arabic and Hebrew are languages in which the text is presented to the user ordered from right to left, but numbers and Latin alphabetic strings within the text are presented left to right.
- Bit manipulation and testing functions
  You can use this function to manipulate and to test a bit in a binary number.
- Cache functions
  Use cache functions to specify a value for each of the cache variables defined for a flow, and additionally, to alter an already specified value for a cache variable.
- Conversion functions
  You can use this function to convert an expression from one datatype to another datatype.
- Date/time functions
  You can use this function to perform various operations on date and time.
- Error handling functions
  You can use this function in evaluating the type of error during map execution.
- External interface functions
  You can use this function to retrieve data from a database from within in a map rule.
- Flow functions
  Use Flow functions to specify a value for each of the flow variables defined for a flow, and additionally, to alter an already specified value for a flow variable.
- Inspection functions
  You can use this function to test and inspect the object.
- Logical functions
  Logical functions provide a way to use logical conditions to display one of several values.
- Lookup and reference functions
  These function search operates by scanning the appropriate set of items in sequence, attempting to match the logical condition.
- Math and statistics functions
  Precede all MATHLIB functions with mathlib->
- Text functions
  These functions are used to convert the text item in a map rule.
- XML functions
  There are several XML functions that you can call from component rules and map rules to process input XML data.
  - VALIDATE
    The VALIDATE function validates the XML input by using the XMLLIB library.
  - VALIDATEEX
    The VALIDATEEX function validates the XML input, and logs the function processing in the directory where the map runs by using the XMLLIB library.
  - XVALIDATE
    The XVALIDATE function validates the XML input.
  - XPATH functions
    The XPATH function queries the XML input.
  - XPATHEX
    The XPATHEX function queries the XML input by using the XMLLIB library, and logs function processing in the directory where the map runs.
  - XSLT functions
    The XSLT function applies an XSLT transformation.
  - XSLTEX
    The XSLTEX function applies an XSLT transformation to the XML input, and logs the function processing in the directory where the map runs by using the XMLLIB library.
- Custom functions
  From the Type Designer or Map Designer, you can create custom functions to call external libraries.
- Date and time format strings
  You can use the listed format strings for numbers, dates and times in functions such as the CURRENTDATETIME, FROMNUMBER, TONUMBER, FROMDATETIME, and TODATETIME.
- Number format strings
  You can create custom number formats by using the given format strings.
- RUN function return codes
  The RUN function return codes and messages might result when using the RUN function.
- Character set codes for CPACKAGE, CSERIESTOTEXT, and CTEXT
  The second argument of the CPACKAGE, CSERIESTOTEXT, and CTEXT functions specifies the character set of the output of the function. The value of the second argument (the character set of the object content), must be a valid character set code.

XPATHEX

The XPATHEX function queries the XML input by using the XMLLIB library, and logs function processing in the directory where the map runs.

This function queries the XML input, provided as a text stream or URL, by using the specified XPath expression and context. The XPATHEX function returns the result of the evaluation and generates the specified trace log file in the directory where the map runs.

Syntax:: XPATHEX (single-text-expression, single-text-expression, single-text-expression, tracelog)
Meaning:: XPATHEX (xml_url_or_xml_fragment, xpath_expression, context_expression, trace_file_name.extension)
Returns:: A single text item

Example

xmllib->XPATHEX( "ipo.in.xml", "./order//item[1]/shipDate", "/ipo:purchaseOrders ", "xpathlog.txt")
Returns the content of the shipDate element from the ipo.in.xml file and generates a trace log of function processing.