From nellardo@concentric.net Wed May 17 16:09:49 2000 Return-Path: Received: (qmail 11982 invoked from network); 17 May 2000 23:09:48 -0000 Received: from unknown (10.1.10.142) by m4.onelist.org with QMQP; 17 May 2000 23:09:48 -0000 Received: from unknown (HELO uhura.concentric.net) (206.173.118.93) by mta3 with SMTP; 17 May 2000 23:09:48 -0000 Received: from marconi.concentric.net (marconi.concentric.net [206.173.118.71]) by uhura.concentric.net (8.9.1a/(98/12/15 5.12)) id TAA20351; Wed, 17 May 2000 19:09:48 -0400 (EDT) [1-800-745-2747 The Concentric Network] Errors-To: Received: from concentric.net ([216.112.226.144]) by marconi.concentric.net (8.9.1a) id TAA25441; Wed, 17 May 2000 19:09:47 -0400 (EDT) Message-ID: <3923246E.F4F73A84@concentric.net> Date: Wed, 17 May 2000 19:12:53 -0400 Reply-To: nellardo@concentric.net Organization: Herds of Wild Buffalo Girls X-Mailer: Mozilla 4.7 (Macintosh; I; PPC) X-Accept-Language: en MIME-Version: 1.0 To: lojban@egroups.com Subject: Re: [lojban] More on lojban programatic semantics: Strong typing and inferencing of types References: <20000516214537.44864.qmail@hotmail.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Brook Conner la xorxes. cusku di'e > 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. Hmmm. You raise an interesting trade-off. Since noi is "incidental", it implies that there isn't another "la stokuot." somewhere that is actually a different kind of "la stokuot." However, most PLs have scoping rules that allow multiple things of the same name - the scoping makes sure the referent of the name is always unambiguous. On the other hand, "poi" implies that the characteristic named is an *essential* aspect of the thing named - this is much closer to the meaning of a type in a PL. > >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. Ehm, I think a namcu is a valid mekso, but I wasn't (yet) talking about type hierarchy - just giving multiple examples. These bridi were meant to be examples of declarations. > >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 My understanding was that naclu (and the other similar gismu) followed a sumti pattern of "x1 is of value x2". So naclu means that x1 is a rational, whose value is given by x2. So in the example above, I would be saying that "la stokuot." is an *unspecified* rational number. X2 is the value. So you could "initialize" a variable at the same time by including x2. > >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. A numerical value in x2 is adimensional, but the things in x1 *are* dimensioned, because the gismu asserts that this is so. Further ,something in x2 could be dimensioned if it was identified earlier as being in a dimension. In this case, either the dimensions have to agree, or there has to be a reasonable conversion. So: la numbr. namcu li pe --- "Number" is a number, whose value is 1 la distens. minli la numbr. -- "Distance" is in miles, the value 1 la triplen. mitre la distens. -- Either an error (la distens. is miles, la triplen. is meters) or conversion of values automatically takes place. la fatsos. grake la distens. -- Definitely an error - "Fatsos" is in grams the value "Distance" _ but distance has been specified to be in miles, and there's no way to convert miles to grams. > It is an interesting topic. Colin Fine posted some interesting > stuff about this kind of thing a couple of years ago. Cool. I'll have to dig in the archives. co'o mi'e brukcr.