Here's a handy toolbar button to have when testing out code: the Formula Language Evaluator.
Type/paste the code you want to test into the dialog, and it presents the results (as best it can) in another text box.
Put the following code behind a toolbar button:
result := @Eval ( @Prompt ( [OkCancelEdit]; "Formula evaluator"; "Enter the formula to evaluate:"; "" ) );
@Prompt([Ok]; "Results window"; @Text(@Implode(result; " ~ " )))
Note that this code displays text lists with a tilde character (~) as a separator between items for functions such as @UserRoles or @DBColumn.