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Overview

GELLO code will be used to calculate the value of 'Total Cost'. It will retrieve the values from 'Number' and 'Cost' and return the result of one multiplied by the other. Click on the RHS in the pane next to IsCalculated for the 'Total Cost'. Then click on  on the far right hand side of this pane, which is now a white background colour.

1. The first bit of GELLO code is nearly always this:prefilled and sets the context

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   let o:observation = parameter[1]Context CEN_Apple_v1::ArchetypeRoot

   
   

2. Now let's set up a local variable to hold the value for instances of the archetype where 'Cost' is entered. Add the following code:

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   letLet Costcost: Integer = if o.isdefined() then o.find_observation('1.2').value_asPQ().value else 0.0 endiftemplate.Apple.Cost.value.oclAsType(PQ).value

   
   

3. Same again for 'Number' - a bit simpler as it is already a number:

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   letLet Numbernumber: Integer = if o.isdefined() then o.find_observation('1.3').value_asReal() else 0.0 endif template.Apple.Number.value.oclAsType(Integer)

   
   

4. Test this code if you like by stepping through it with the Step button Image Removedcompile button.Image Added
   
   

5. Next thing is to do the algorithm line that produces the result:
    

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   letLet Resultresult_Real: IntegerReal = Costcost * Numbernumber

   
   

6. But 'Total Cost' is a Physical Quantity*, so the result needs to be returned in this form. This line of code just declares what needs to be returned by the GELLO v. 1 expression:

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   Factory.PhysicalQuantity (Result,--- PQ{value = result_Real, unit = '$')}

   
   

   
   
   

7. Running So the whole bit of GELLO code in the MO Gello Editor (which in turn is embedded in the MO Template Editor) looks like:
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   And the thing running in Preview Archetype:
    
   
   
   
8. Don't forget to save the archetype!!