[developers] Trigger rules still being requested

Ann Copestake aac10 at cam.ac.uk
Thu Feb 11 01:05:06 CET 2016


The comment about construction from corpora was really about big 
grammars - i looked at the ERG trigger rules about a year ago, and was a 
bit horrified ...

For small grammars, is it really hopelessly inefficient to just run in 
the mode where all the empty semantics items are added to the chart?  
Does it simply not work if you have no trigger rules?  (I admit not 
having tried this for years.)

However, if not, it seems to me that the extract from a corpus technique 
could work with small grammars assuming you've got a suitable set of 
test sentences before you start to generate.  i.e., you'd parse those 
and accumulate trigger rules automatically from the parsed set, 
repeating as you expand the grammar.  It doesn't matter if the trigger 
rules are very liberal, after all.

Ann

On 10/02/2016 23:14, Emily M. Bender wrote:
> The tdl output is helpful to the extent that it shows people what the 
> value of TRIGGER should
> be, but that's about it.  It's particularly unhelpful when the trigger 
> rules are actually there...  Also,
> learning trigger rules from parsed/treebanked data sounds interesting, 
> but won't help at all
> in the case of starter grammars, which we *do* want to be able to 
> generate.
>
> Emily
>
> On Wed, Feb 10, 2016 at 3:00 PM, Ann Copestake <aac10 at cam.ac.uk 
> <mailto:aac10 at cam.ac.uk>> wrote:
>
>     Hmm - does anyone find the TDL output for the trigger rules
>     helpful? because, having looked at the code, I would prefer to
>     remove that facility completely unless it has support, since it's
>     hardwiring type and feature names into the code.   i.e., I would
>     rather go back to the original behaviour which meant that warning
>     messages were output (if there were no appropriate existing
>     trigger rules) without the TDL being suggested.  I believe oe may
>     feel the same way.
>
>     The trigger rule mechanism is a mess, in fact.  Learning trigger
>     rules from parsed/treebanked data is feasible, but too big a
>     project for me to take on.
>
>     Ann
>
>
>     On 10/02/2016 18:47, Dan Flickinger wrote:
>>
>>     Hi Emily -
>>
>>
>>     I ran into this behavior too when doing the SWB-oriented grammars
>>     for the grammar engineering course I taught with Tom last
>>     quarter.  The culprit turns out to be the function
>>     index-lexicon(), which right at its end cheerfully emits those
>>     warning/advice messages for all semantically empty entries
>>     regardless of whether trigger rules have been defined.  Since the
>>     same shortcoming is repeated in the separate function
>>     reindex-lexicon(), it proved to be easier for me to correct this
>>     by changing the function make-trigger-tdl() which they both call,
>>     so that the global mt::*transfer-triggers* is checked before
>>     emitting the warning for each semantically empty lexical entry. 
>>     Here is the patched version of this function analogous to what I
>>     added to my grammars' user-fns.lsp file:
>>
>>
>>     (defun make-trigger-tdl (empty-semantics-lexical-entries)
>>       (let ((empty-no-trigger-entries
>>          (loop for id in empty-semantics-lexical-entries
>>                unless (or #+:mt
>>                   (gethash id mt::*transfer-triggers*)
>>                   nil)
>>                collect id)))
>>        (loop for x in empty-no-trigger-entries
>>           do
>>         (format t "~%~%~a_gr := generator_rule &
>>     [ CONTEXT.RELS <! [ PRED \"non_existing_rel\" ] !>,
>>       FLAGS.TRIGGER \"~a\" ]."
>>             (string-downcase x)
>>             (string-downcase x)))))
>>
>>
>>     I expect that Ann or Stephan could see a more elegant way to
>>     achieve this effect, but this patch might be a useful temporary
>>     expedient.
>>
>>
>>       Dan
>>
>>
>>     ------------------------------------------------------------------------
>>     *From:* developers-bounces at emmtee.net
>>     <mailto:developers-bounces at emmtee.net>
>>     <developers-bounces at emmtee.net>
>>     <mailto:developers-bounces at emmtee.net> on behalf of Emily M.
>>     Bender <ebender at uw.edu> <mailto:ebender at uw.edu>
>>     *Sent:* Wednesday, February 10, 2016 7:43 AM
>>     *To:* developers
>>     *Subject:* [developers] Trigger rules still being requested
>>     Dear all,
>>
>>     In the Matrix derived grammars, we have the following in  lkb/script:
>>
>>     ;;;
>>     ;;; SSH 2012-03-27 This invokes trigger rules for semantically empty
>>     ;;; lexical entries. The trigger rules themselves should be in
>>     ;;; trigger.mtr in the grammar directory. The documentation on
>>     trigger
>>     ;;; rules: http://moin.delph-in.net/LkbGeneration
>>     <http://moin.delph-in.net/LkbGeneration>
>>     ;;;
>>     ;;; SSH 2013-05-23 The semi.vpm file needs to be loaded *before* the
>>     ;;; trigger.mtr file in lkb/script for correct interaction.
>>     ;;;
>>
>>     (mt:read-transfer-rules
>>      (list
>>       (lkb-pathname (parent-directory) "trigger.mtr"))
>>       "Generation trigger rules"
>>       :filter nil :task :trigger :recurse nil :edges 200 :subsume nil)
>>
>>     ;;;
>>     ;;; Matrix-derived grammars often have stable enough semantic
>>     ;;; representations that the grammar can usefully be tested
>>     ;;; by generating from them.  The function index-for-generator()
>>     ;;; must be called for generation to be enabled.  In grammars with
>>     ;;; small lexica, this takes a trivial amount of time.  If
>>     ;;; generation is not being used regularly, and the indexing
>>     ;;; is taking too long, comment out the following.
>>      index-for-generator()
>>     ;;; can also be run from the expanded LKB top menu, under
>>     ;;; Generate.
>>     ;;;
>>
>>     (index-for-generator)
>>
>>     It is my understanding that (index-for-generator) is what is
>>     behind the messages
>>     suggesting trigger rules for semantically empty lexical entries,
>>     but even though
>>     we call it after loading the trigger rules, we still get messages
>>     such as the following:
>>
>>
>>
>>     Is there something else we're supposed to do so that we only see
>>     those messages
>>     when an entry truly lacks a trigger rule?
>>
>>     Thanks,
>>     Emily
>>
>>     -- 
>>     Emily M. Bender
>>     Professor, Department of Linguistics
>>     Check out CLMS on facebook!
>>     <http://www.facebook.com/uwclma>http://www.facebook.com/uwclma
>
>
>
>
> -- 
> Emily M. Bender
> Professor, Department of Linguistics
> Check out CLMS on facebook! http://www.facebook.com/uwclma

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