Here is the list of available MQL expressions:
| Literals |
Strings: "Hello World"Booleans: true or falseNumbers: 3, 0.08Lists: ["winter", "spring", "summer", "autumn"]Maps: {"winter" = "cold", "summer" = "warm"}No value: null
|
| Variables | myClass |
| Dotted notation | myClass.isAbstract(), myClass.namespace.name |
| Concatenation | "Hello" + "World" |
| Arithmetical operations | a + b, a * b |
| Comparison operations | name == "Account", size > 2 |
| Logical operations | ! isAbstract, a || b |
| Type checking | myClassifier instanceof uml21.Actor |
| Range access | myString[0], myList[1..4] |
| Default value expression | myProperty.type.name ? "String" |
| Transient links | myClass#targets.iterator() |
| Static field or method access | System.getProperty("myProperty") |
| Constructor call | java.util.Properties.new() |
Parentheses can be used to group expressions:
(a + b) * (2 - c)
The following table shows the precedence assigned to the operators.
The operators in this table are listed in precedence order:
the higher in the table an operator appears, the higher its precedence.
Operators with higher precedence are evaluated before operators with a relatively lower precedence.
Operators on the same line have equal precedence.
When binary operators (operators with two parameters, as + and -)
of equal precedence appear next to each other, they are evaluated in left-to-right order.
| postfix operators | [subStringRange] . (methodParameters) |
| unary operators | +expr -expr ! |
| multiplicative | * / % |
| additive | + - |
| relational | < > <= >= |
| equality | == != |
| logical AND | && |
| logical OR | || |
| numerical range | .. |
Note that the precedence rules are the same as in Java, C or JavaScript, except that MQL has some operators that do not exist in those languages.