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Functions and Expressions
Use HCL Link functions and expressions to create component rules and map rules.
Logical functions
Logical functions provide a way to use logical conditions to display one of several values.
EITHER
The EITHER function returns the result of the first argument that does not evaluate to "none".

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.
  - ALL
    The ALL function evaluates a series of conditions and returns "true" if they all evaluate to "true"; otherwise returns "false".
  - BINDABS
    Use this function in a component rule for the implementation of binding and iterative evaluation.
  - EITHER
    The EITHER function returns the result of the first argument that does not evaluate to "none".
  - IF
    You can use the IF function for conditional logic.
  - ISALPHA
    You can use ISALPHA when you need to know whether a text string is all alphabetic characters.
  - ISLOWER
    The ISLOWER function tests a text object to see if it contains all lowercase alphabetic characters.
  - ISNUMBER
    The ISNUMBER function tests a text object to determine whether it contains all numeric characters.
  - ISUPPER
    The ISUPPER function tests a text object to determine whether it contains all uppercase alphabetic characters.
  - NOT
    Use the NOT function to test a condition and have it return the inverse of its "true" or "false" result. For example, you want the function to return "true" if the condition results in "false".
  - OR
    Use the OR function to test whether one of a series of conditions is true.
  - WHEN
    You can use the WHEN function in a component rule to test for the validity of one object based on another object.
- 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.

EITHER

The EITHER function returns the result of the first argument that does not evaluate to "none".

Syntax:: EITHER (single-general-expression { , single-general-expression } )
Meaning:: EITHER ( try_this { , if_none_try_this } )
Returns:: A single object

The EITHER return methods work in the following ways:

Returns...: When...
try_this: try_this does not evaluate to "none"
if_none_try_this: try_this evaluates to "none"
the next if_none_try_this: the first if_none_try_this evaluates to "none"

Examples

EITHER ( OrderDate Field , CURRENTDATE ( ) )
If OrderDate Field does not evaluate to "none", it is returned. If OrderDate Field evaluates to "none", the current system date (using CURRENTDATE) is returned.
EITHER ( LOOKUP (PriorityCd:Msg , CustID:Msg = "93X" ) , 8 )
This example returns the result of the LOOKUP if that result does not evaluate to "none"; otherwise, it returns the second argument of 8.
EITHER (IF (SomeCode = "C" , CustomerID:Input) , IF (SomeCode = "S" , SupplierID:Input) , IF (SomeCode = "O" , Reference#:Input) , "####" )
If SomeCode is C and CustomerID:Input has a value, EITHER returns the value of CustomerID. Otherwise, if SomeCode is S and CustomerID:Input has a value, EITHER returns the value of SupplierID. Otherwise, if SomeCode is O and Reference#:Input has a value, EITHER returns the value of Reference#. If none of those conditions result in a value, EITHER returns "####".
You can use EITHER when you want a default value when an expression evaluates to "none" and the expression might cause common arguments to produce an unintended result. For example, use:
EITHER (LOOKUP (PriorityCd:Msg , CustID:Msg = "93X") , 8)

-instead of-

IF (PRESENT (LOOKUP (PriorityCd:Msg , CustID:Msg = "93X" ) ), LOOKUP ( PriorityCd:Msg , CustID:Msg = "93X" ) , 8 )