Passing functions into variable arguments

[#1]

I am using variables with arguments to hold my expressions which are used through my application. I pass the variable the respective field to be calculated which works just fine. However, I cannot find a way to pass a function via the argument into the expression without error.

Working example (in simple terms, where Num is the field that holds values):

Normal expression: sum(Num)

Variable for expression: vCalcSum = sum($1)

Called in expression: =$(vCalcSum(Num))

Problem example;  I cannot find a way to pass a function to the same variable, in this case using if():

Normal expression: sum(if(Type=1,Num,0))

Variable for expression (same as above): vCalcSum = sum($1)

Called in expression: =$(vCalcSum(if(Type=1,Num,0)))

I have tried using $ expansion on the inner logic to no avail and am stuck. Thoughts, ideas, tricks??? Thanks!

[Gysbert_Wassenaar]

Try set analysis:  $(vCalcSum(  {<Type={1}>} Num  ))

[#3]

Thanks. For the simple if() in my example I can use set analysis, but I guess I was looking for a more comprehensive solution that would work for any type of function. Maybe a better example would have been:

if(Type=1,Num,Num*2)

But then again, maybe I'm overthinking this!