Subject: Re: [lojban] More on lojban programatic semantics: Strong typing and inferencing of types

From: "Jorge Llambias" <[email-masked]>
Date: Tue, 16 May 2000 14:45:37 PDT

la brukcr cusku di'e

>So, for example, you can use "poi" to annotate sumti with type
>information, or simply an appropriate selbri for "declaring" variables:
>
>ko jarco la stokuot. poi mekso -- show the "stock-quote", which is a
>mathematical expression

For annotation {noi} is better than {poi}.
{la stokout poi mekso} would be used to restrict the reference to
{la stokuot} which is a mekso, as opposed to any other {la stokuot}
which is something else.

>la stokuot. mekso -- "stock-quote" is a mathematical expr.
>
>la stokuot. namcu -- "stock-quote" is a number.

I think a mekso cannot be a namcu, it's supposed to be an
unevaluated expression, but I may be wrong. The mekso part
of the language has never really been worked out.

>la stokuot. saclu -- "stock-quote" is a rational number

Again, for {saclu} I think it is only the symbolic representation,
not the number that is at stake. You would be saying for example
that {la stokout} is the name of the string of symbols 0.75,
not the number 0.75=3/4

>The diversity of "number" gismu that include units has a nice side
>effect of reducing the kinds of goofs that crashed the recent Mars
>mission: if it's "minli", then it is miles. If it is "mitre", then it is
>meters.

I'm not sure what you mean here. I think it is the other way
around, because the units are included in the gismu, the numbers
(se minli, se mitre) are actually all adimensional.

>Now, of course, this implies a type hierarchy for lojban gismu. Which
>might be a whole kettle of worms (unless it has already been done).

Never done, but there were some attempts and discussions about it.

>Determining that "grake" and "bunda" (grams and pounds) are in one
>category, while "snidu" and "jeftu" (seconds and weeks) are in another
>is straight-forward.

{grake} and {bunde} are not strictly in the same category
(mass and weight, respectively) but anyway something can have
both mass and duration, so you must be talking about se grake,
se snidu. But these are all pure numbers, all in the same category.

>But determining other class hierarchies might be
>more complex. I don't *think* lojban gismu were defined with a specific
>taxonomy in mind (lojbab? JWC?).

Nothing explicit, but some types can be extracted.

>As always, I welcome thoughts and feedback.....

It is an interesting topic. Colin Fine posted some interesting
stuff about this kind of thing a couple of years ago.

co'o mi'e xorxes

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