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Functions and Expressions
Use HCL Link functions and expressions to create component rules and map rules.
Error handling functions
You can use this function in evaluating the type of error during map execution.
VALID
You can use the VALID function to perform conditional processing based on whether an external interface function executes successfully.

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.
  - CONTAINSERRORS
    The CONTAINSERRORS function tests a valid object to see whether it contains any objects in error.
  - FAIL
    You can use the FAIL function to abort a map based on map or application specific logic.
  - GETXMLERRORMSG
    Use this function on an output card to return an XML validation error message when a map runs against invalid XML input.
  - ISERROR
    The ISERROR function tests an object to see if it is in error.
  - ONERROR
    Use ONERROR in component rules to add user-defined error messages to the data section of the audit log.
  - REJECT
    The REJECT function returns the content of an object in error as a text item.
  - QUIT
    You can use the QUIT function to stop a map at a specific point during map execution.
  - VALID
    You can use the VALID function to perform conditional processing based on whether an external interface function executes successfully.
- 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.
- 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.

VALID

You can use the VALID function to perform conditional processing based on whether an external interface function executes successfully.

The VALID returns the result of the first argument if it is valid; otherwise, returns the second argument.

Syntax:: VALID ( single-text-expressions , single-general-expression )
Meaning:: VALID ( function_that_can_fail , return_value_if_function_fails )
Returns:: A single text expression

VALID returns the result of the evaluation of function_that_can_fail if it is valid. If the function fails, VALID returns return_value_if_function_fails.

The following functions can fail:


DBLOOKUP	GET
DBQUERY	PUT
DDEQUERY	RUN
EXIT

Examples

SomeObject = VALID ( RUN ( "mymap.mmc" , "-OF1 mydata.txt" ) , FAIL ( "My RUN failed!" ) )
If the RUN function returns an error return code, the VALID functions returns none, the map aborts, and the message My RUN failed! is reported under Execution Summary in the execution audit log.

Related functions

DBLOOKUP
DBQUERY
DDEQUERY