new-tag placement in COPY rules

[Kevin Brubeck Unhammer]

In the Divvun grammar checker project, we have input

"<jierpmálaš>"
"jierpmálaš" A Sg Nom &syn-super-part2

and want to write a rule like

COPY (Superl &SUGGEST) TARGET (A &syn-super-part2) IF (NOT 0 (&SUGGEST));

where the expected output is

"<jierpmálaš>"
"jierpmálaš" A Superl &SUGGEST Sg Nom &syn-super-part2

What are the heuristics for placement of the new tags here? I can't seem
to make them go anywhere except at the end; e.g. the actual output of
the above rule is

"<jierpmálaš>"
"jierpmálaš" A Sg Nom &syn-super-part2
"jierpmálaš" A Sg Nom &syn-super-part2 Superl &SUGGEST COPY:4

Is there a simple way to control tag placement? I know it's possible to
do

COPY (Superl Sg Nom &SUGGEST) EXCEPT (Sg Nom) TARGET (A &syn-super-part2) IF (NOT 0 (&SUGGEST));

and get

"<jierpmálaš>"
"jierpmálaš" A Sg Nom &syn-super-part2
"jierpmálaš" A &syn-super-part2 Superl Sg Nom &SUGGEST COPY:4

which is pretty much what I want. I don't care about the &-tags, but the
other tags go into an FST where order matters. But with two numbers and
seven cases we have to have 14 COPY rules. Add possessive tags and so
on, and it quickly turns unmaintainable.


I notice that the docs for SUBSTITUTE do specify insertion point ("at the
last removed tag"), so a better workaround might be

COPY (&SUGGEST) TARGET (A &syn-super-part2) IF (NOT 0 (&SUGGEST));
SUBSTITUTE (A) (A Superl) TARGET (A &syn-super-part2 &SUGGEST) IF (NOT 0 (Superl));

but then the rule writer has to juggle a lot of "marker tags" in order
to avoid adding the Superl to irrelevant readings or getting loops.

I know it's not trivial to make heuristics for tag placement here, but
it seems like it could be possible to have a heuristic similar to the
SUBSTITUTE heuristic one, like

place <extra tags> after the last removed tag from <extra tags>,
otherwise at the end of the reading

so that you could write

COPY (A Superl &SUGGEST) EXCEPT (A) TARGET (A &syn-super-part2) IF (NOT 0 (&SUGGEST));

(On the other hand, if people depend on the current behaviour, perhaps new
rule options BEFORE/AFTER <tag> might be a better solution …)


--

Kevin Brubeck Unhammer

[Tino Didriksen]

Replied inline...

On 9 June 2017 at 12:44, Kevin Brubeck Unhammer <aper...@unhammer.mm.st> wrote:

I know it's not trivial to make heuristics for tag placement here, but
it seems like it could be possible to have a heuristic similar to the
SUBSTITUTE heuristic one, like

  place <extra tags> after the last removed tag from <extra tags>,
  otherwise at the end of the reading

so that you could write

  COPY (A Superl &SUGGEST) EXCEPT (A) TARGET (A &syn-super-part2) IF (NOT 0 (&SUGGEST));

(On the other hand, if people depend on the current behaviour, perhaps new
rule options BEFORE/AFTER <tag> might be a better solution …)

Using the except tag could work, but like Substitute it'd really be more of a hack.

I am vastly more in favour of Before/After as insertion point - this could also be extended to Substitute. Given we have the keywords we might as well make use of them.

-- Tino Didriksen

[Kevin Brubeck Unhammer]

Tino Didriksen <ma...@tinodidriksen.com> čálii:

I'd be very happy with that solution :) Keywords are more explicit and
easier to reason about.

[Tino Didriksen]

Implemented in svn and latest nightly. ADD/MAP/COPY now takes BEFORE|AFTER before the target. E.g.

ADD (x) BEFORE (y z) (n) ;

COPY (x) EXCEPT (y) AFTER (z) (n) ;

-- Tino Didriksen

[Kevin Brubeck Unhammer]

Tino Didriksen <ma...@tinodidriksen.com> čálii:

> Implemented in svn and latest nightly. ADD/MAP/COPY now takes BEFORE|AFTER before the target. E.g.
>
> ADD (x) BEFORE (y z) (n) ;
>
> COPY (x) EXCEPT (y) AFTER (z) (n) ;

That look like exactly what we want, nice!