Stream: Archive Mirror: Isabelle Users Mailing List

Topic: [isabelle] bug in Isabelle2005


view this post on Zulip Email Gateway (Aug 17 2022 at 13:27):

From: Jeremy Dawson <Jeremy.Dawson@rsise.anu.edu.au>
There seems to be a bug in the processing of inductive definitions in
Isabelle2005

bug = Main +

consts
evens :: "nat set"

inductive "evens"
intrs
evens_0 "0 : evens"
evens_next "n : id evens ==> Suc (Suc n) : evens"
monos id_mono

end

Jeremy

view this post on Zulip Email Gateway (Aug 17 2022 at 13:28):

From: Stefan Berghofer <berghofe@in.tum.de>
Jeremy Dawson wrote:
This problem only affects old theories, for which Isabelle generates
ML files containing the theory extension commands. It seems that
the ML interface of the inductive definition package has been changed,
but the generator for the theory extension code has not been adapted
to these changes. To fix the problem, you have to make the following
modification in the file HOL/thy_syntax.ML:
In function

fun inductive_decl coind =
let
...
fun mk_params ((recs, ipairs), monos) =
let val big_rec_name = space_implode "_" (map (scan_to_id o unenclose) recs)
...
in
";\n\n\
...
\ InductivePackage.add_inductive true " ^
(if coind then "true " else "false ") ^ srec_tms ^
sintrs ^ " " ^ mk_list (no_atts monos) ^ " thy;\n\

replace the line containing (no_atts monos) by

sintrs ^ " " ^ mk_list (no_atts (map (fn s => "Name " ^ s) monos)) ^ " thy;\n\

Note that the old non-Isar theory file format will no longer be supported
in future releases of Isabelle anyway, so porting your theories to the new
format is a good alternative to the above fix.

Greetings,
Stefan

view this post on Zulip Email Gateway (Aug 17 2022 at 13:28):

From: Makarius <makarius@sketis.net>
There is indeed a problem with the ML code generator for 'inductive', but
the above is an old non-Isar theory, which is not really supported any
more.

It is very easy to convert old theories to the current format; ML proof
scripts work as before with the help of use_legacy_bindings. Your theory
then looks like this (ignoring the fact that id_mono may not exist):

theory Scratch
imports Main
begin

consts
evens :: "nat set"

inductive evens
intros
evens_0: "0 : evens"
evens_next: "n : id evens ==> Suc (Suc n) : evens"
monos id_mono

ML {* use_legacy_bindings (the_context ()) *}

end

Note that the above 'bug' is no longer present in the current Isabelle
development version, because the old theory format has been discontinued
altogether.

Makarius

view this post on Zulip Lukas Stevens (Aug 24 2022 at 08:12):

From: Jeremy Dawson <Jeremy.Dawson@rsise.anu.edu.au>

Stefan Berghofer wrote:

Note that the old non-Isar theory file format will no longer be supported
in future releases of Isabelle anyway, so porting your theories to the new
format is a good alternative to the above fix.

Greetings,
Stefan

In converting a non_Isar theory file to Isar format,
what is the equivalent in Isar of the "rules" section of a non-Isar theory?

By the way, what has happened to the Introduction to Isabelle - it seems to have disappeared from the doc directory?

Jeremy


Last updated: Nov 21 2024 at 12:39 UTC