[developers] Bug in interactive unification

[Stephan Oepen]

further toward perfection in the LKB interfaces :-).

guy, can you try asking for the type display by typing in |1| (including
the vertical bars).  i suspect the prompt windows just uses the lisp read()
function, which will interpret a string of digits as a number, rather than
as a symbol.  in TDL parsing, however, all (unquoted) type names are
interpreted as symbols.  the |...| syntax will force symbol interpretation.
 this would be easy to fix, and likely applies in other input routines that
prompt for type or grammar entity names.

regarding LUI communication, i am inclined to suggest that this is a bug in
the #D[...] reader ... woodley, how could you not agree?

cheers, oe

ps: i had originally drafted this message  yesterday; i suspect the LKB
input fix that john has in mind is likely along the lines above?


On Fri, 13 Nov 2020 at 12:36 Guy Emerson <gete2 at cam.ac.uk> wrote:

> Hi John, Woodley, and Stephan,
>
> Thank you all for your fast responses!  This has been really helpful.
>
> I have come across two further small bugs, both to do with type names
> consisting entirely of numeric characters.  Such names are allowed
> internally in the LKB, and in terms of unification, they seem to behave
> exactly as I expect them to.  I couldn't find documentation suggesting that
> numeric characters should be treated differently.  However:
>
> (1) in the View>Expanded type pop-up window, a string of numeric
> characters gives the message "Not defined - try again.", even if the type
> is defined.  (When the pop-up window shows a drop-down instead of a text
> box, such types appear in the list.)
>
> (2) Displaying such a type causes LUI to crash.  For example, a type named
> "1" causes a crash, with the following in the log file (where the value of
> RESULT is 1):
>
> process_complete_command(): `
> avm 3 #D[null-with-push-1-here RESULT: #D[1 REST: NULL]]
> "null-with-push-1-here - expanded"
>  '
>
> Type of dag was not a symbol or string (type 2)
>
>
> Best,
> Guy
>
>
> Am Mi., 11. Nov. 2020 um 21:52 Uhr schrieb Stephan Oepen <oe at ifi.uio.no>:
>
>> hi john:
>>
>> > Aha, the constraint object in your LUI log has unbalanced brackets.
>> Guessing which bracket is wrong, I've changed another LKB robust unifier
>> function, and attach a new version of the file debug-unify2-patch.lsp
>>
>> many thanks for the quick diagnostics and fixes!  i looked over both
>> your patches, and they seem like just the right fix to two genuine
>> bugs that have been lurking (for the past sixteen or so years :-) in
>> the interactive unifier behind the LUI drag-and-drop interface.  i
>> have just picked them up (and added my own fix for the LUI display of
>> atomic dags) and committed these changes to both the LOGON and FOS
>> repositories.
>>
>> best wishes, oe
>>
>
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