[Attempto] Assign unique variables problem

[Kaarel Kaljurand]

Hi,

On Thu, Sep 27, 2012 at 12:56 PM, Pierre-Alexandre Voye
<ontologiae at gmail.com> wrote:
>
> I need to express something which refers to variable I defined, and it seems
> impossible.
>
> User creates a webpage W1. W1 contains two fields F1 and F2. F1's name is
> "Login". F2's name is "password". W1 contains a button B1. B1's name is
> "Connexion".
> If WebUser clicks on B1 and F1 is not empty then Ocsigen calls Login's
> service.
>
> It fails with an error :
>
> value="Redefined variable: F1"
>     repair="Assign unique variables."

this is a tricky case, e.g. I needed to look at the syntax tree to
figure out what's wrong...
(Note that the syntax tree is calculated before reference resolution
takes place, so in this case it is present although no DRS results.)

You probably expect that "two fields F1 and F2" is parsed as

    (two fields) (F1 and F2)

but the actual parse tree is

    (two fields F1) and (F2)

i.e. "F1" is a plural NP. As a result you must refer to it in a plural
context, e.g.:

    F1 _are_ not empty

As always, the solution is to write simpler (possibly more verbose)
sentences, in this case replace the NP coordination with VP
coordination:

    W1 contains a field F1 and contains a field F2.

Of course, in this case the parser could maybe return a better error
message, e.g. "trying to redefine a plural variable as singular".

Best regards,
Kaarel