I have been going through certain requirements in my current project which helped me to find variables with parameters.
if($1 = <value1>, expression1, if($1 = <value2>, expression2.......))))
Note : We can also use multiple parameters of different data types and can be referred with $1, $2.....,$n.
Steps to create:
-> Create a variable in settings-> variable overview
-> Add a variable in the variable overview editor
-> In the definition area create if conditions with above syntax.
->$(variablename(parameter 1, parameter2...parameter3...parametern))
PFA qvw file which contains a variable with a single parameter : The first value calculates Savings and the second value calculates Savings%.
Note: Although this feature is powerful , the variable editor shows "error" or "underlines" in red which is a bug in Qlikview, please check the variable in a text box or in an expression for its validity.