Functions

Use functions when you are concatenating strings, formatting strings, counting records in a collection, and setting default values on a control. All functions begin with $_.

Supported functions include:

$_concat(param1, ...) : string
Converts and concatenates all parameters to a single string:
```
 $_concat("StartDate: ", $LeaveRequests.StartDate, " - EndDate: ",
        $LeaveRequests.EndDate) 
```
You must provide at least one parameter. If you provide only one parameter, it is converted to a string and returned by the function.
$_now() : date Returns the current date and time as dateTime.

$_format.date(date value, format option) : string Returns the formatted string of a date value. Parameters include:

date value – date typed value.
format option – valid values are: short, medium, long

Examples:

 //returns for example "1 January 2012" if the date is 2012-01-01 and format option is
        long   
$_format.date($LeaveRequests.StartDate, long)

//returns for example "1 Jan 2012" if the date is 2012-01-01 and format option is
        medium   
$_format.date($LeaveReuqests.StarDate, medium)

The phone's region setting is used to format the date.

$_format.datetime(date value, format option) : string
Returns the formatted string of a date and time value and supports these parameters:
- date value – date typed value.
- format option – valid values are: short, medium, long.
Example:
```
 //long format of today's date and time, result: "1 January 2012 11:55"
$_format.datetime($_now(), long)   
```
The phone's region setting is used to format the date and time
$_date(year, month, day) : date
Creates a date typed value from parameters and supports these parameters:
- year – year value as int or float.
- month – month value as int or float.
- day – day value as int or float.
Example:
```
//returns "Since 1 January 2012" (UK locale was set on the phone) $_concat("Since", 
$_format.date($_date($_year($_now(), 1, 1)), long))
```
$_count(binding_id) : int
Returns the number of entries in a collection:
```
//returns Leave Requests (6)
$_concat("Leave Requests (", $_count($LeaveRequests), ")")
```
$_isNull(value) : int Checks whether the parameter is a null value or nonexistent. Returns false or true.
$_isNotNull(value) : int Checks whether the parameter value is null. Returns true if the parameter value is not a null value, or false otherwise.
$_isEmpty(value) : int
The function returns true if:
- Its parameter is a null value.
- The referred variable or data field of a BO in its parameter does not exist.
- The referred variable or data field of a BO exists, but its value is either an empty string ('') or an NSData instance with zero length.
Otherwise, this function returns false.
$_isNotEmpty(value) : int Returns true for values for which $_isEmpty returns false.
$_isExisting(value) : int The function returns true if its parameter refers to an existing variable or data field of a BO; false otherwise. The function also returns true when the referred variable or data field of a BO is null, or empty string, because the parameter refers to an existing object.
$_isNotExisting(value) : int Returns true for values for which $_isExisting returns false).
$_year(date value) : int
Returns the year as an int from a date value:
```
 //Returns the current year   
$_year($_now())   
```