oldk1331 wrote:
>
> (56) -> PositiveInteger has KONVERT(INFORM)
>
> (56) false
> Type:
> Boolean
> (57) -> queue([1,2,3])::INFORM
>
> Cannot convert the value from type Queue(PositiveInteger) to
> InputForm .
>
> (57) -> queue([1,2,-3])::INFORM
>
> (57) (($elt (Queue (Integer)) construct) (construct 1 2 - 3))
> Type:
> InputForm
>
>
> Similar for NNI.
>
> This is clearly a bug. Should we just add KONVERT(INFORM)
> to the EXPORTS of PositiveInteger, or there is a deeper reason
> and requires a different fix.
Well, apparently InputForm was done for specific purpose
(creating functions for plotting) and most other parts
were unimplemented. So no deep reason for absence
of convertion for PositiveInteger. OTOH there is related
issue: should convertion make effort to preserve types?
If no than very simple fix should work. If we want to
preserve types, than several existing convertions would
need changes. The issue of types came, because
preserving types is needed for equality 'x = interpret(x::INFORM)'.
Currently I think that we should weaken this requirement
and instead of 'x::INFORM' have 'atType(x::INFORM)' in
the equality (otherwise all (or most) convertions need
to perform equivalent of 'atType').
--
Waldek Hebisch
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