Literals
Description
A literal is a notation for representing a fixed value in source code. Almost all programming languages have notations for atomic values such as integers, floating-point numbers, and strings, booleans and characters.
Literals are often used to initialize variables, for example, in the following, '1' is an IntegerLiteral which is assigned to a new created variable 'a' of data type Integer. And the three letter string in "cat" is a StringLiteral, which is assigned to a new created variable 's' of data type String.
Integer a = 1;
String s = "cat";
Types
The following types of Literals exists
Simple Data Type
The following table lists all available literals for Simple Data Types:
Data Type | Literal | Sample |
Boolean | {True|False} | Boolean flag = True; |
Integer | Integer number | Integer n = 1; m = n - 1234; |
Float | Floating-point number | Float n = 1.2; m = n + 12.345; |
String | Quoted sequence of characters | String str = "This is a text" str = StringConcatenate(str, " definded as a literal in OTX."); |
ByteField | Sequence of bytes in hex started with a & | ByteField bytes1 = &12 34 56 78 90 AB CD EF ByteField bytes2 = &1234567890ABCDE; // equals &01 23 45 67 89 0A BC DE |
Container Data Type
The following table lists all available literals for Container Data Types:
Data Type | Literal | Sample |
List | List one or more elements in braces seperated with comma | List<Integer> integerList = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; List<List<String>> stringList = { { "Text11", "Text12" }, { "Text21", "Text22", "Text23" }, { "Text31" } }; |
Map | List one or more key value pairs in braces seperated with comma; in each pair of key value, the key connects with the value by the equal sign | Map<String, Integer> myMap1 = { "Key1"=1234, "Key2"=567, "Key3"=89 }; Map<String, List<Integer>> myMap2 = { "Key1"={ 1, 2, 3, 4 }, "Key2"={ 5, 6, 7 }, "Key3"={ 8, 9 } }; |
Complex Data Type
Literals for Complex Data Type have the following syntax:
@DataTypeName:MemberValue1/MemberValue2/../MemberValueN
Where DataTypeName is the name of the related data type and MemberValue the value of the corresponding value. Sample:
// ResultStateLiteral for enumeration value POSITIVE
@ResultState:POSITIVE;
// UserExceptionLiteral to throw an user defined exception
@UserException:"FATAL_ERROR"/"There is a fatal error occured!";
// QuantityLiteral for a value of 1.2 %
@Quantity:1.2/"%"/1;