[opentheory-users] importer for Isabelle

[Brian Huffman]

I've hardly looked at it since I wrote it. It was never incorporated
into the Isabelle codebase. I suppose it would probably work with the
latest Isabelle, because it uses only the low-level proof kernel api,
which doesn't change much any more.

I'll have to look around to see where I have a copy of the source
code; that was a couple of computers ago. Did you want to try to do
something with it?

- Brian


On Sat, May 23, 2015 at 5:13 AM, Ramana Kumar <ramana at member.fsf.org> wrote:
> Hi Brian,
>
> What's the status of your OpenTheory importer? Does it work with the
> latest Isabelle? Was it incorporated into the main code base?
>
> Cheers,
> Ramana
>
> On 15 April 2011 at 17:34, Brian Huffman <brianh at cs.pdx.edu> wrote:
>> On Thu, Apr 14, 2011 at 7:03 PM, Joe Hurd <joe at gilith.com> wrote:
>>> Hi Brian,
>>>
>>> That is really great work! Am I right in thinking you can import the
>>> parser-1.5 article binding all the input symbols and axioms to
>>> existing ones in Isabelle? I would have guessed that Isabelle type
>>> classes would have managed to get in the way at some point, but
>>> perhaps this would only be for converting Isabelle proofs to
>>> OpenTheory format?
>>
>> Yes, each of the input constants of the article is mapped to a
>> pre-existing Isabelle constant. Some of these existing Isabelle
>> constants happen to be overloaded, but that doesn't cause any
>> problems. This mapping of constant names does not even need to be
>> one-to-one; for example, I imagine that "Number.Natural.+" and
>> "Number.Integer.+" would map to the same overloaded "plus" constant in
>> Isabelle.
>>
>> Of course, exporting proofs from Isabelle is a completely different story.
>>
>>> You mentioned that you prove a lot of theorems that the OpenTheory
>>> article relies on, but it seems you could reduce this by processing a
>>> set of OpenTheory packages that don't make any definitions. When I was
>>> designing the standard theory library I tried to isolate packages that
>>> made definitions and have them export just a minimal theorem interface
>>> - most of the theorems are proved in packages that make no definitions
>>> and so can be safely run to populate the [opentheory] set of theorems.
>>
>> Your idea of keeping definitions in separate, minimal modules is a
>> good design. I'm sure I could have greatly reduced the number of
>> [opentheory] lemmas that I needed by finding the right additional
>> article files to import; I was just too lazy to figure out how the
>> packages were organized.
>>
>>>> The importer should also extend these tables whenever it defines a new
>>>> constant or type, but I haven't implemented this yet. Another nice
>>>> feature would be a way for users to influence how the importer chooses
>>>> names for newly-defined constants and types. Right now it takes the
>>>> names directly from the strings in the article file, which isn't so
>>>> nice for names like "HOLLight._dest_rec" (Isabelle's parser can't
>>>> handle names that start with underscores).
>>>
>>> You should find that constants and type operators with names like this
>>> are never exported from a theory (i.e., never appear in exported
>>> theorems), so it's perfectly safe to normalize their names to
>>> something more acceptable to Isabelle. They are `local definitions'
>>> that are used only in proofs.
>>
>> Actually, it seems like it would be safe to rename *any* constant
>> (whether exported or not) to any name that I want in Isabelle, as long
>> as the importer keeps track of the name mapping so that later imports
>> can use the same names.
>>
>> I suppose I should write an "import_name" function that converts from
>> OpenTheory names to Isabelle-friendly ones. It would be nice to
>> parameterize this by a list of user-specified exceptions to the
>> mapping, so you could say something like, "import this article, but
>> when you define constant 'foo', call it 'bar' instead."
>>
>>>> Once I clean up the code, I'm not sure what I should do with it... I
>>>> suppose I could add it to the Isabelle repo, but I'm not sure if I
>>>> want to advertise to Munich crowd that I've been doing all this work
>>>> that is unrelated to finishing my thesis :)
>>>
>>> I would very much like to see it live on in some fashion - my hope is
>>> that more and more theories will be converted to OpenTheory packages,
>>> and your code could be used to import them into Isabelle in a
>>> principled way.
>>
>> I suppose I'll add it to the Isabelle distribution at some point,
>> maybe after I finish writing my thesis. In the meantime, I guess I can
>> post the code to the list, so it will be archived and people can try
>> it out.
>>
>> - Brian
>>
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