OCLOperators whentrue
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When you have an immutable OCL expression, you always return a value - and then the [[Documentation:OCLOperators casetruefalse|OCLOperators_caseTrueFalse]] is good. However, when using the MDriven Action-Language that allows updates of objects, another construct is introduced to compact things even more: | |||
boolean.whentrue(dothis):boolean | |||
The return is always the '''arg0'''. | |||
=== '''Example:''' === | |||
let x=SomeObject.SomeEnum in ( | |||
(x=#Enum1).whentrue(SomeObject.DoYourThing1); | |||
(x=#Enum2).whentrue(SomeObject.DoYourThing2); | |||
(x=#Enum3).whentrue(SomeObject.DoYourThing3) | |||
) | |||
'''''Fun fact:''''' "whentrue" and logical "and" are implemented the same - the logical "and" only evaluates arg1 of arg0 is true (lazy evaluation) and "whentrue" does the same thing, but always returns arg0. | |||
This means that a convoluted but equivalent construct can be: | |||
let x=SomeObject.SomeEnum in ( | let x=SomeObject.SomeEnum in ( | ||
(x=#Enum1) | (x=#Enum1) and (SomeObject.DoYourThing1;true); | ||
(x=#Enum2) | (x=#Enum2) and (SomeObject.DoYourThing2;true); | ||
(x=#Enum3) | (x=#Enum3) and (SomeObject.DoYourThing3;true) | ||
) | ) | ||
[[Category:OCLOperators]] | |||
{{Edited|July|12|2025}} | |||
Latest revision as of 04:56, 11 February 2025
This page was created by Hans.karlsen@mdriven.net on 2021-12-04. Last edited by Stephanie@mdriven.net on 2025-02-11.
When you have an immutable OCL expression, you always return a value - and then the OCLOperators_caseTrueFalse is good. However, when using the MDriven Action-Language that allows updates of objects, another construct is introduced to compact things even more:
boolean.whentrue(dothis):boolean
The return is always the arg0.
Example:
let x=SomeObject.SomeEnum in ( (x=#Enum1).whentrue(SomeObject.DoYourThing1); (x=#Enum2).whentrue(SomeObject.DoYourThing2); (x=#Enum3).whentrue(SomeObject.DoYourThing3) )
Fun fact: "whentrue" and logical "and" are implemented the same - the logical "and" only evaluates arg1 of arg0 is true (lazy evaluation) and "whentrue" does the same thing, but always returns arg0.
This means that a convoluted but equivalent construct can be:
let x=SomeObject.SomeEnum in ( (x=#Enum1) and (SomeObject.DoYourThing1;true); (x=#Enum2) and (SomeObject.DoYourThing2;true); (x=#Enum3) and (SomeObject.DoYourThing3;true) )