Evaluate function in teststand status expression

Question

Hello,
I can not understand the meaning of function Evaluate() in below sentence,and can not find the explanation in help files,could someone help me ?
Step.DataSource != "Step.Result.PassFail" ? Step.Result.PassFail = Evaluate(Step.DataSource) : False, Step.Result.PassFail ? "Passed" : "Failed" 
Solved!
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Answer 1

As an added point of reference, we use the "Evaluate()" function to to parse Variables in a Step Name for TestStand steps.  This makes our steps very readable and FAST to code in TestStand.
For example our tests to communicate to a device might be to write a value to a value to a specific parameter, such as writing a Setpoint Value.  So the TestStand step name would look like:
[] Writeetpoint(1)=200
    Where Setpoint is the Parameter Name, (1) represents the Instance, and 200 is the value written
However we use the Evaluate() function to parse out variables:
Locals.sParameter = "Setpoint"
Locals.nInstance = 1
Parameters.nValue = 200
[]Write:{L.sParameter}({L.nInstance})={P.nValue}
   (We use a shortened version of L. for Locals., P. for Parameters., etc. because it doesn't take up so much space on the Step Name)
We have a library subsequence (Check for Curly Brackets to be parsed) that parses out any variables that are enclosed in the {} curly brackets.
  Replace "L." with "Locals.", etc. and then parse out the variables in the Pre-Expression, 
and then EVALUATE the variables in the Post-Expression:
Locals.sTemporary ="RunState.Caller.RunState.Caller."& Locals.sVariable,
'If the variable exists, resolve it, if not replace it with '{ERROR}' and continue.
Locals.sTemporary =( PropertyExists(Locals.sTemporary)? Evaluate(Locals.sTemporary)  :"{ERROR}"),
'Put the resolved variable (or error) back in place of its name
Locals.sWorkingString = Locals.sBeforeVar & Locals.sTemporary & Locals.sAfterVar
Also, during runtime, if there happens to be an error in the StepName, we can edit it and continue on using a "Set Step Name" tool.
Mike