Syntax question for ArcGIS ICalculator object

Question

This is a silly question, but I have this code snippet that I can't figure out:

'Define a calculator for NewArea field
    pCalculator = New Calculator
    With pCalculator
        .Cursor = pCursor
        .PreExpression = "Dim dbarea as double" & vbCrLf _
                       & "Dim pArea as IArea" & vbCrLf _
                       & "Set pArea = [Shape]" & vbCrLf _
                       & "dbArea = pArea.area"
        .Expression = "dbArea"
        .Field = "NewArea"
    End With

    'Calculate the field values of NewArea field
    pCalculator.Calculate()

What is pCalculator calculating here? What is [Shape] in this context? I'm migrating this old VBA code to Python, and I'm stuck at this segment. Thanks in advance.

A more general question, what is the significance of the square brackets in the pre-expression? Are they placeholders for the expression?

Answer 1

All this is doing is calculating the area of each feature. You can easily do the same thing with the Python version of the parser with !shape.area!. See the documentation.