[Attempto] Assign unique variables problem

[Norbert E. Fuchs]

On 27 Sep 2012, at 13:46 , Kaarel Kaljurand <kaljurand at gmail.com> wrote:

> 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".

As Kaarel wrote, "two fields F1 and F2" in English is understood as (field F1 and field F2), while in ACE it is understood as (two fields F1 and F2). Recall that a variable always refers to the immediately preceding noun phrase.

Actually, you can use NP coordination – also called conjunctive plural – instead of VP coordination writing

  W1 contains a field F1 and a field F2.

to achieve what you want.

Regards.

   --- nef