Shell Programming and Scripting

I am trying to use a pattern-list match in korn shell using a variable and it always seems to regard the pattern-list as a literal:

Using the directory names explicitly in the pattern-list works fine:
ls @(test|test1)/test.txt

and returns:
test/test.txt

Trying to use a variable for this purpose fails:
export patternList=test\|test1
ls @(${patternList})/text.txt

and returns:
@(test|test1)/text.txt: No such file or directory

I tried to interpret the way paths are dealt with in the ksh man page, but failed to understand it properly which is probably why I don't understand why this doesn't work. Can someone tell me how to make this work or why it does not work?

It does not work because shell performes substitution only onetime. (Why - it is another question and I do not know it.)
Than means the variable is substituted to it's value in first review of the comand by the shell and second time the shell does not process the file name substitution which is required to evaluate (maybe, better to say: expand) the @(test|test).
To correct that the 'eval' command works:

Code:

> ls @(test|test1)/test.txt
test1/test.txt  test/test.txt
> cat @(test|test1)/test.txt
another test file in test1 dir <<<
proba
> var=test\|test1
> echo $var
test|test1
> eval cat @($var)/test.txt
another test file in test1 dir <<<
proba

Perfect, works like a champ. Thanks for the quick reply.