Assume that I have a parameter variable "bar" and I have three database fields labeled "bar1", "bar2", "bar3", all under a stored procedure called "bar":

-Database Fields
  -foo
    -bar1
    -bar2
    -bar3
-Parameter Fields
  -bar

I want to create a formula field such that I can call each field without using a select/switch/if statements (because the parameter bar is dynamic) by using a parameter variable nested in a database field variable:

{foo.{bar}}

But when I do this, Crystal Reports tells me:
"The function identifier "}" is unknown"

Currently, I am implementing it by using switch condition:

select {?Breakdown By}
    case "Project Name":  {IssueOverview.Project Name}
    case "Reporter":  {IssueOverview.Reporter}
    case "Assignee": {IssueOverview.Assignee}
    case "Type": {IssueOverview.Type}
    case "Priority": {IssueOverview.Priority}
    case "Status": {IssueOverview.Status}
    case "Satisfaction": {IssueOverview.Satisfaction}

"?Breakdown By" is a static list with those possible values. The reason why I wanted to use nested variables is because it would reduce maintenance. Such a statement above could be reduced to:

{IssueOverview{?Breakdown By}}

That way every time the "?Breakdown By" parameter is changed, I won't have to modify this formula as well. And further down the road, "?Breakdown By" will be dynamic as it may change frequently.