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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.
Automatic item format conversions
When an item is assigned an output value, the map designer will automatically convert an item with the same interpretation (either number, text, date, or time) from one presentation to another.

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.
  - Expressions
    An expression is a statement about data objects. Expressions are used in component rules in the schema designer and in map rules in the map designer.
  - Literals
    A literal is a constant value. A literal may be a number or a text string.
  - Data object names
    A data object is referenced in an expression by its name.
  - Evaluating expressions
    Expressions are evaluated based on the context in which data object names, literals, operators, function names and map names appear in the expression, and the data on which it operates. .
  - Operators
    Operators are used for arithmetic functions and text functions on items.
  - Using functions in expressions
    Functions perform a particular action on its input arguments.
  - Map names in expressions
    Map names in expressions that are used in map rules represent calls to functional maps.
  - Expressions that evaluate to NONE
    The following discussion explains how the map designer evaluates an expression when expressions within it evaluate to "none".
  - Evaluated expressions assigned to output items
    When an output item is defined, then it is determined from the result of the evaluated expression.
  - Automatic item format conversions
    When an item is assigned an output value, the map designer will automatically convert an item with the same interpretation (either number, text, date, or time) from one presentation to another.
    - Numeric precision
      The precision of a numeric value is the number of digits that are used to show that value.
- 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.
- 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.

Automatic item format conversions

When an item is assigned an output value, the map designer will automatically convert an item with the same interpretation (either number, text, date, or time) from one presentation to another.

For example, if you want to map an item that is a number and whose presentation is integer to an item that is also a number but whose presentation is decimal, the map designer will automatically convert it.

The map designer fills in missing information in date and time conversions in the following way:

Dates with a year, but no century. The century will be determined using the CenturyDerivation map setting.
Missing part of an output date format. If a portion of the format of an output date cannot be derived from the input date, the missing part will have pound characters (#) in its place. For example, if 09/98 is the date for an input with a format string of MM/YY and that date was mapped to an output date with a format of MM/DD/YY, the output date would be built as 09/##/98.
Missing part of an output time format. If a portion of the format of an output time cannot be derived from the input time, the missing part will have zeroes (0) in its place. For example, if 12:14 is the data for an input with a format string of HH12:MM and that time was mapped to an output time with a format of HH:MM:SS, the output date would be built as 12:14:00.

To convert a number to text, a date or time, or vice versa, you must use a function to perform the conversion. For example, to convert a date to text, use the function DATETOTEXT.