Message-Id: <m0jxLuV-0001DAC@snark.thyrsus.com>
From: cowan (John Cowan)
Subject: Changes to grammar:  21-28
To: lojban-list
Date: Tue, 9 Jul 91 13:31:36 EDT
Status: RO

Change 21:

*ANNULLED*


Change 22:

CURRENT LANGUAGE:

CU is treated like the elidable terminators, although it does not terminate.

PROPOSED CHANGE:

Make CU optional (handled directly by grammar rules) rather than elidable.
This does not change the grammatical status of any text; it is simply a
change to internal mechanisms in the parser.

RATIONALE:

This change assists correct error recovery in the parser.


Change 23:

CURRENT LANGUAGE:

FAhO is currently an elidable terminator for the end of text.  Text refers
not only to an entire expression, but also to quoted (with LU/LIhU) and
parenthesized (with TO/TOI) material.  In addition, FAhO is allowed at the
end of a very-long-scope sentence group marked with TUhE/TUhU.  In all three
of these cases, the FAhO is redundant to the regular elidable terminator.

PROPOSED CHANGE:

Treat FAhO extra-grammatically as an overriding end of parsable input.
It would no longer be allowed at the end of quoted or parenthesized text.

RATIONALE:

This change assists correct error recovery in the parser.  It is also closer
to the original spirit of FAhO, which was intended to assist mechanical
Lojban users in determining when to terminate input (similar to the RETURN
or ENTER keys in more conventional programs).


Change 24:

*ANNULLED*


Change 25:

CURRENT LANGUAGE:

The flag "pe'o", selma'o PEhO, is currently used to mark forethought mekso
operators.

PROPOSED CHANGE:

Make "pe'o" optional.

RATIONALE:

"pe'o" is not needed to keep the grammar unambiguous, but may still be
helpful as a heuristic to avoid confusing human readers.


Change 26:

CURRENT LANGUAGE:

A time interval specified with ZEhA must be preceded by a time direction
specified with PU.  An interval without a direction looks like an origin
specification and is not allowed.  Space intervals have a similar restriction.

PROPOSED CHANGE:

Allow bare ZEhA as a time interval and bare VIhA, VEhA or VEhA+VIhA as a 
space interval.  Remove origin specifications from the language, and
space interval, with no directions specified.  If a direction is wanted
for the interval, allow it after the interval word.  Remove origin-size
specifications as a special mechanism; origin sizes are set using KI,
just like origin locations.  (A side effect of this change is that FEhE is
always required to mark space interval modifiers.)

RATIONALE:

There is no logical reason why intervals must have a direction.  The sentence
"mi ve'ivi'u xadni" meaning "I small-interval-ly-three-dimensionally am-a-body"
is ungrammatical without this change, but is perfectly sensible.


Change 27:

CURRENT LANGUAGE:

The current use of full mathematical expressions is limited to two areas:
after LI to form sumti, and as quantifiers.  In the latter use, parentheses
must be used around any mekso other than a simple number.

Simple numbers and letteral-strings can also be used in some other places:
with -MOI to form selbri, with -MAI to form utterance ordinals, and with
-ROI to form quantified tenses, and after XI to make subscripts.

PROPOSED CHANGE:

Allow richer expressions after XI and before MOI.  The grammar of XI
is extended to allow XI VEI mex /VEhO/ as a subscript, allowing any
mekso within parentheses (same rule as for quantifiers).

With -MOI, the rule has to be more complex, since simply allowing
any quantifier + MOI produces conflicts.  Instead, we extend the
syntax of ME-conversion so that ME sumti /MEhU/ MOI is a legal kind
of selbri.  Typically the sumti will be either a LI construct, a
"le ni" construct, or some kind of anaphora.

RATIONALE:

We need to be able to say "x sub (n + 1)" for mathematical and scientific
text, as well as being able to talk about the "(n + 1)th occurrence"
of an event.


Change 28:

CURRENT LANGUAGE:

Official doctrine states that the sumti tcita of a bridi constitute nonstandard
places which are co-equal with the regular numbered places.  However, there
is no way to make these places the subject of a description by moving them
into a numbered (specifically, the x1) place.

PROPOSED CHANGE:

Add JAI+tag as the equivalent of a SE conversion.  (JAI is a new selma'o.)
This is usable only on selbri, not in the other places where SE is legal.
The result is that the se tcita sumti comes to occupy the x1 place, and the
original x1 place is moved to a new "x0" place, which can be labelled with
the cmavo "fai" (of selma'o FA).

RATIONALE:

It is currently messy to say "the time of my going to the store"; this
looks like an abstraction, but does not match any existing abstractor.
It can be handled quite neatly with "le jai ca klama be fai mi bei le zarci".
In particular, when a place is meant to be an abstract sumti, and a
concrete sumti appears ("sumti raising"), these JAI-based descriptors
provide sumti access to modal places as well as standard ones.