From wetblu!uunet!andrew.cmu.edu!yh0a+ Tue May 15 13:33:53 1990 Return-Path: Received: by marob.masa.com (/\=-/\ Smail3.1.18.1 #18.7) id ; Tue, 15 May 90 13:33 EDT Received: by wetblu.hollander.com (/\=-/\ Smail3.1.16.1 #16.12) id ; Tue, 15 May 90 13:20 EDT Received: from cbmvax.UUCP by uunet.uu.net (5.61/1.14) with UUCP id AA12994; Tue, 15 May 90 11:50:57 -0400 Received: by cbmvax.cbm.commodore.com (5.57/UUCP-Project/Commodore Jan 13 1990) id AA17974; Tue, 15 May 90 11:33:39 EDT Received: by snark.uu.net (smail2.3) id AA14224; 15 May 90 10:32:21 EDT (Tue) Received: from PO2.ANDREW.CMU.EDU by uunet.uu.net (5.61/1.14) with SMTP id AA09549; Mon, 14 May 90 19:23:53 -0400 Received: by po2.andrew.cmu.edu (5.54/3.15) id for lojban-list%snark@uunet.uu.net; Mon, 14 May 90 19:24:55 EDT Received: via switchmail; Mon, 14 May 90 19:24:51 -0400 (EDT) Received: from po3.andrew.cmu.edu via qmail ID ; Mon, 14 May 90 16:19:06 -0400 (EDT) Received: from pcs2.andrew.cmu.edu via qmail ID ; Mon, 14 May 90 16:14:38 -0400 (EDT) Received: from pcs2.andrew.cmu.edu via qmail ID ; Mon, 14 May 90 16:14:34 -0400 (EDT) Received: from mms.0.1.401.MacMail.0.5.CUILIB.3.45.SNAP.NOT.LINKED.pcs2.andrew.cmu.edu.rt.r3 via MS.5.6.pcs2.andrew.cmu.edu.rt_r3; Mon, 14 May 90 16:14:32 -0400 (EDT) Message-Id: Date: Mon, 14 May 90 16:14:32 -0400 (EDT) From: Yary Richard Phillip Hluchan To: lojban-list@snark Subject: Some things about lojban Status: RO I received the level 0 mailings about half a year ago. I read them over, took some notes, and wanted to post some observations- unfortunatly I couldn't find this lists address, and now that I have it, I've lost my notes! (In fact, I don't even have the level 0 mailing in front of me. gismu are the basic words, that fit inside the places defined by the lujvo, right? This is from memroy) The mailing mentioned that there was some trouble with representing mathematical concepts, but there was no description of the current method. Could you mail me a copy of the math grammar? One big problem that I remember- and it would take a lot of work to fix- is lojban's use of the postfix grammar. If I remember correctly, the reason postfix was chosen was to make machine interpretation easier, since most machines used a stack-based architechture. However, today's machines don't need to store data structures on a stack; stacks can be used but they're no easier to represent than a binary tree, an array, or a DAG. (In fact, I suspect it would be better to represent a block of lojban text as a list of trees, with the lujvo at the root of each tree... just a hunch). If it is necessary to store the text as a stack, it would be simple to parse from prefix to postfix. Using the arguments above, there's no clear reason to prefer either prefix or postfix notation. So why go through all the work of rewriting textbooks, etc to go with prefix? Human comprehension: with the current setup, a person has to keep track of up to five gismu before hearing how they fit together (the lujvo). Since most people have a short-term memory of about seven items, people won't notice this as a problem. With more complicated structures, there are times when people go near the limit of their short term memory. Putting the lujvo first gives the reader a framework in which to place the subsequent gismu. Since the reader is now able to chunk the incoming words together, s/he can understand the information easier. Furthermore, putting the lujvo first might help a parsers error detection. If a lujvo is left out from a postfix stream, the parser will not be able to detect the error until it reaches the next (not left out) lujvo. With prefix notation, the parser could immediatly see that it had at least one gismu too many and flag it. I am not too sure of the language and place structures, though, so this may be wrong. It would take a bit of work to convert from postfix to prefix, but I think the long-term comprehension benefits would be worth the effort. What do you think? I am sorry that I don't have the grammar rules here, with some concrete examples I'm sure I could make a more convincing argument.