Stream: Archive Mirror: Isabelle Users Mailing List

Topic: [isabelle] Delete code_const declaration in sub-target

Email Gateway (Aug 19 2022 at 11:45):

From: Andreas Lochbihler <andreas.lochbihler@inf.ethz.ch>
I have set up the code generator with code_const and code_type to use the type and
operations from the SML standard basis library, namely the Word16 structure.
Unfortunately, PolyML does not provide this optional structure, so I would like to
configure the Eval target of the code generator such that the code generator forgets about
these configurations from the super-target SML and uses the Isabelle code equations for
evaluation. How can I delete a code_const / code_type declaration in a sub-target? None of
the following seems worked:

1. code_type ... (Eval "")
   raises Match in code_printer.ML upon export_code

2. code_type ... (Eval -)
   (inspired by the Haskell code_instance example in the code generator tutorial)
   gives an outer syntax error at -

3. code_type ... (Eval "-")
   raises Match in code_printer.ML upon value [code]

Andreas

Email Gateway (Aug 19 2022 at 11:46):

From: Florian Haftmann <florian.haftmann@informatik.tu-muenchen.de>
Hi Andreas,

Indeed. I will consider multi-inheritance for code targets, but not in
the near future. In the meanwhile maybe it's best to clone the target
setup from Heap_Monad.thy for a target SML_word_imp.

Hope this helps,
Florian
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Email Gateway (Aug 19 2022 at 11:55):

From: Florian Haftmann <florian.haftmann@informatik.tu-muenchen.de>
Hi Andreas,

How can I delete a code_const / code_type
the short answer is: that is not possible – it's the ancient issue that
monotonicity does not go well along with deletions.

Concerning your problem, I would recommend to setup a separate target
e.g. »SML_word« derived from »SML« (see Imperative-HOL for examples).
This is IMHO even the cleaner approach, because target setup for »SML«
should not rely on anything not in PolyML.

Hope this helps,
Florian
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Email Gateway (Aug 19 2022 at 12:01):

From: Andreas Lochbihler <andreas.lochbihler@inf.ethz.ch>
Hi Florian,

Thanks for the suggestion with a separate sub-target. Before I go that way, I would like
to double check that I understand the implications. AFAIK the targets in the code
generator are arranged in an inheritance tree, i.e., one cannot "merge" different setups.
So, if I introduce such a target SML_word, then I won't be able to use the Imperative_HOL
variant SML_imp. Right?

Best,
Andreas

Last updated: Nov 21 2024 at 12:39 UTC