[Ur] puzzled about unification error

[Adam Chlipala]

The issue is that a tuple has a record type, while a general expression 
enclosed in parentheses needn't. [Theme.tabbed] requires a record 
argument.  One fix would be to do:
     {A = blah}
instead of:
     (blah)

On 03/27/2017 12:31 PM, Marko Schütz Schmuck wrote:
> When I use the "course" example from upo/examples and I use as
> function main
>
> val main =
>      Theme.tabbed "Course Home Page"
>                ((Some "Forum",
>                  GlobalForum.ui),
>                 (Some "Users",
>                  EditUsers.ui))
>
> urweb compiles it. But when I cut it down a little more to
>
> val main =
>      Theme.tabbed "Course Home Page"
>                ((Some "Users",
>                  EditUsers.ui))
>
> urweb reports unification failure: