Data Types and Type Conversion
The expression language internally deals with the following types (and returns values of these types):
Type | Description |
Null | Null value means "no value". This value may be written to the Data Table cell only if field is nullable. |
Object | This is a super-type of all types. If some function is declared to return an Object, it may return value of any type, depending on the input parameters. |
Number | This is a super-type of all numeric types. If some function is declared to accept a number, it may accept Integer, Long, Float or Double. In addition, all other objects will be converted to numbers on a best effort basis. |
Integer | 32-bit signed integer number. |
Long | 64-bit signed integer number. |
Float | A floating point number. |
Double | A double-precision floating point number. |
String | String of any length. Strings may also contain binary data. |
Boolean | TRUE or FALSE |
Color | An 8-bit RGB color value. |
Date | A timestamp that includes both date and time parts. May be consumed by date/time processing functions. |
Data Table | A Data Table. |
All types have their analogs among Data Table field types.
 | Expressions which evaluate to a Float or Double numeric type follow the IEEE_754 standard for arithmetic. For example, the expression |
Type Conversion
The expression language processing engine does its best to perform all necessary type conversion and evaluate an expression to get some result. For example, if a numeric argument is passed to a function that accepts strings, the number is auto-converted to its string representation. Another example: if a floating point number is added to an integer number the resulting value is also a floating point number. This helps avoid rounding errors.
If proper type conversion is not possible, the evaluation of an expression fails with an error.
The explicit type conversion is performed by using type conversion functions.
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