Can anyone help with me with the syntax for using lists to drive an equation?

Example:

I have a list called "Hshape"

In this list:

     Circle

     Rectangle

     Oval

I want my equation to function something like this.

"Feature" = iif ( "Hshape" like Circle, "suppressed", "unsuppressed")

if "Hshape" equals Circle, then suppress "Feature"

I cannot figure out the syntax to accomplish this.

Thanks in advance.