Re: [lojban] erasure words

[Robin Lee Powell <rlpowell@digitalkingdom.org>]

On Thu, May 13, 2004 at 10:38:04PM +0100, Zefram wrote:
> Looking at the "sa" debate, it appears that people have come up with
> more than one useful set of semantics for it:

No kidding.

> * erase up to and including the previous instance of the following
> word
> 
> * erase up to and including the previous word of the same selma'o as
> the following word

That's the official interpretation.

> * erase until the next word can legally follow

This is obviously untenable.

> To which I'd like to add another possibility along the same lines:
> 
> * erase up to and including the previous word that is in the same
> category as the following word, using broader categories than selma'o,
> so that "le broda sa la broda" preprocesses to "la broda"

If you would like to produce a list of selma'o that can be considered
equivalent for this purpose, I'd be willing to consider immplementing
that.  I don't *think* there are any cases where LE and LA are not
interchangeable.

> And I came to the conclusion that we've got more useful erase
> operators than we have words assigned to them.  

That's what experimental cmavo are for.

> Perhaps some of the expanded cmavo space should be earmarked for erase
> operators.
>
> Btw, this earmarking is a protocol engineering technique, and I highly
> recommend it.  

Really?  So you think CIDR is bad, then?

> If a Lojban parser sees a cmavo that it doesn't know, being able to
> tell at least whether it is an erase operator would be *very* helpful.

No, it wouldn't.  Not in the least.  The erase operators are all
different selma'o, and are all handled completely independantly.

> I also think part of the "sa" debate is happening because people are
> trying to define it in a very low-level way, operating on words
> without regard for grammar.  Such low-level operators are indeed
> useful, but they're not sufficient for a good preprocessor.

Just for the record, my grammar has no pre-processor, and it uses a
grammatical formalism that is more expressive than LR(n), for any n
(including infinity).

> I'd like to have some higher-level erase operators that parse what has
> gone before and act on that.  These would be used to correct
> higher-level errors: because they require grammatical text they
> couldn't fix grammatical errors, but would be useful when the wrong
> grammatical text has been said.  Operators to think about:
> 
> * erase the sumti currently in progress or just completed
> 
> * erase the bridi currently in progress or just completed

Both of these can be done with sa.

> * erase back to and including the opening delimiter matched by the
> closing delimiter that follows the erase word

How is "lu broda SA_LIKE li'u da" == da better than "lu broda sa lu si
da" == da?

-Robin

-- 
http://www.digitalkingdom.org/~rlpowell/  ***  I'm a *male* Robin.
"Many philosophical problems are caused by such things as the simple
inability to shut up." -- David Stove, liberally paraphrased.
http://www.lojban.org/  ***  loi pimlu na srana .i ti rokci morsi