[Agda] nullary copattern matching

[Thorsten Altenkirch]

It would be relevant if we allow indexed records and coinductive types as discussed recently.

Thorsten

On 20/03/2018, 23:21, "Agda on behalf of Andreas Abel" <agda-bounces at lists.chalmers.se on behalf of abela at chalmers.se> wrote:

     > What is the syntax for copattern matching on a record with zero fields?
    
    There isn't any yet, although Jesper and I discussed adding it:
    
       record True : Set where
    
       triv : True
       triv .()
    
    The syntax would be a post-fix absurd projection pattern.
    
    Do you have an interesting application for it?  With eta-equality, there 
    is not so much use it seems, since the same can be obtained by
    
       triv = _
    
    Cheers,
    Andreas
    
    On 20.03.2018 23:12, Christian Sattler wrote:
    > What is the syntax for copattern matching on a record with zero fields? 
    > I could not find anything in the documentation. For pattern matching on 
    > a data type with zero constructors, we have syntax for denoting an 
    > impossible case, but what about the analogous situation for copatterns? 
    > Note that C-c C-c will happily produce invalid code ("missing definition").
    > 
    > Christian
    > 
    > 
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