3.3. Behavior package

3.3. Behavior package
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3.3.1. Control Structures

Kermeta provides basic control structures : block, conditional branch, loop, and exception handling. Here there an excerpt of the Meta-model describing control structures. Each basic control structures derives from the Expression concept.

Figure 3.9. Control structure

3.3.2. Variables

Figure 3.10. Use of variables

3.3.3. Call Expressions

Figure 3.11. use of exceptions

3.3.3.1. CallSuperOperation

In the following example, the type of super[ParentClass](element) is CallSuperOperation :

class ParentClass {
    operation op(element : Integer) : Integer is do
        result := element + 1
    end

}

class ChildClass inherits ParentClass {
    method op(element : Integer) : Integer is do
        result := super[ParentClass](element)
    end
}

3.3.3.2. CallVariable

The type of callvar , below, is CallVariable:

var myvar : Integer
var callvar : Integer init 4
// 
myvar := callvar

A special case, when calling a lambda expression : the type of lf in the assignment of res, is CallVariable.

var lf : <Integer->Integer>
var res : Integerlf := function  { i : Integer | i.plus(1) }
// The type of lf, below, is CallVariable
res := lf(4)

3.3.3.3. CallResult

The type of result is CallResult

operation op() : Integer is do
    result := 61
end

3.3.3.4. CallFeature and SelfExpression

The type of self is a SelfExpression!
The type of attr in the body of the operation myoperation is CallFeature (a callfeature on self ), and so is the type of myoperation(4) (a callfeature on a ).

class A {
    attribute attr : Integer
    operation myoperation(param : Integer) : Integer is do
        result := self.attr + param
    end
}
class B {
    operation anotheroperation() : Integer is do
        var a : A
        result := a.myoperation(4)
    end
}

3.3.4. Assignment

Figure 3.12. Kermeta assignment expression

In the following example, thetarget is of type CallExpression and thevalue is of type Expression .

var num : Numeric
var thetarget : Integer
var thevalue : Integer
// assignment : thetarget->target, thevalue->value
thetarget := thevalue
// casting : a is casted into the type of num which is Numeric.
num ?= a

3.3.5. Literals

Figure 3.13. Kermeta Literal Expression

var i : Integer
i := 5    // 5 is a IntegerLiteral
var s : String 
s := "I am a string" // "I am a string" is a StringLiteral

3.3.6. Lambda Expression

Figure 3.14. Kermeta lambda expressions

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