[Agda] agda halting problem
Andreas Abel
andreas.abel at ifi.lmu.de
Thu Jul 5 20:57:00 CEST 2012
Termination checking happens only after type-checking. This is a design
flaw, and a long standing issue to be fixed.
http://code.google.com/p/agda/issues/detail?id=42
It is in the back of my mind and should be implemented during the next
major overhaul of the termination checker.
Cheers,
Andreas
On 05.07.12 7:50 PM, Dan Doel wrote:
> On Thu, Jul 5, 2012 at 12:07 PM, Daniel Peebles<pumpkingod at gmail.com> wrote:
>> I don't think there's an easy way to check. Not-obviously-terminating
>> definitions will get marked in pink if typechecking completes, but if you go
>> and use one directly in a type somewhere and the definition really doesn't
>> terminate on the input in the type, then the typechecker won't terminate. So
>> if you use possibly non-terminating functions in types, you might want to
>> split up your file to make sure nothing that would normally be pink is
>> hanging your typechecker.
>
> Although I don't run into this often, it is kind of unfortunate. Have
> any of the implementors considered a flag that would make type
> checking fail if a type contains something rejected by the termination
> checker? Is that even possible at present (i.e. are type and
> termination checking interleaved)?
>
> -- Dan
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--
Andreas Abel <>< Du bist der geliebte Mensch.
Theoretical Computer Science, University of Munich
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andreas.abel at ifi.lmu.de
http://www2.tcs.ifi.lmu.de/~abel/
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