Weird "case" statement behavior (at least to me...), can someone please explain this to me?

Hello all,

Today I ran into a problem which toke me a long time to find the cause. It is with the "case" statement. First I show you something that is very simple and that does work:

testString = "one"
case( testString
    ( "one"
        printf("it is 1!\n")
    )
    ( "two"
        printf("it is 2!\n")
    )
    ( t
        printf("it is something else!\n")
    )
)

testString = "two"
case( testString
    ( "one"
        printf("it is 1!\n")
    )
    ( "two"
        printf("it is 2!\n")
    )
    ( t
        printf("it is something else!\n")
    )
)

testString = "bla"
case( testString
    ( "one"
        printf("it is 1!\n")
    )
    ( "two"
        printf("it is 2!\n")
    )
    ( t
        printf("it is something else!\n")
    )
)

When you run this code (just copy-past into CIW...) the output of the case statements is as you would expect:

it is 1!
it is 2!
it is something else!

However, if you specify a variable like so:

testOptions = list( "one" "two" )

And replace the "case" statement with this:

case( testString
    ( nthelem( 1 testOptions )
        printf("it is 1!\n")
    )
    ( nthelem( 2 testOptions )
        printf("it is 2!\n")
    )
    ( t
        printf("it is something else!\n")
    )
)

The output is not what I expected:

it is something else!
it is something else!
it is something else!

Testing the "nthelem" part shows no problem, it perfectly outputs the right string (or whatever you put in the list).

If you do the same with a "cond" statement (using the "nthelem" statement), it works perfectly fine.

My question: what is happening here? Why is the result what it is, and not what I was expecting?

Thanks in advance.

With kind regards,

Sjoerd