<!-- MHonArc v2.4.4 --> <!--X-Subject: Re: [MUD-Dev] string parsing --> <!--X-From-R13: "Tryvk O. Qebrf" <sryvkNkf1.fvzcyrk.ay> --> <!--X-Date: Thu, 30 Oct 1997 18:44:03 +0000 --> <!--X-Message-Id: 199710301846.TAA27432#xs1,simplex.nl --> <!--X-Content-Type: text/plain --> <!--X-Head-End--> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> <html> <head> <title>MUD-Dev message, Re: [MUD-Dev] string parsing</title> <!-- meta name="robots" content="noindex,nofollow" --> <link rev="made" href="mailto:felix#xs1,simplex.nl"> </head> <body background="/backgrounds/paperback.gif" bgcolor="#ffffff" text="#000000" link="#0000FF" alink="#FF0000" vlink="#006000"> <font size="+4" color="#804040"> <strong><em>MUD-Dev<br>mailing list archive</em></strong> </font> <br> [ <a href="../">Other Periods</a> | <a href="../../">Other mailing lists</a> | <a href="/search.php3">Search</a> ] <br clear=all><hr> <!--X-Body-Begin--> <!--X-User-Header--> <!--X-User-Header-End--> <!--X-TopPNI--> Date: [ <a href="msg00176.html">Previous</a> | <a href="msg00178.html">Next</a> ] Thread: [ <a href="msg00181.html">Previous</a> | <a href="msg00180.html">Next</a> ] Index: [ <A HREF="author.html#00177">Author</A> | <A HREF="#00177">Date</A> | <A HREF="thread.html#00177">Thread</A> ] <!--X-TopPNI-End--> <!--X-MsgBody--> <!--X-Subject-Header-Begin--> <H1>Re: [MUD-Dev] string parsing</H1> <HR> <!--X-Subject-Header-End--> <!--X-Head-of-Message--> <UL> <LI><em>To</em>: <A HREF="mailto:mud-dev#null,net">mud-dev#null,net</A></LI> <LI><em>Subject</em>: Re: [MUD-Dev] string parsing</LI> <LI><em>From</em>: "Felix A. Croes" <<A HREF="mailto:felix#xs1,simplex.nl">felix#xs1,simplex.nl</A>></LI> <LI><em>Date</em>: Thu, 30 Oct 1997 19:46:17 +0100 (MET)</LI> </UL> <!--X-Head-of-Message-End--> <!--X-Head-Body-Sep-Begin--> <HR> <!--X-Head-Body-Sep-End--> <!--X-Body-of-Message--> <PRE> cg#ami-cg,GraySage.Edmonton.AB.CA (Chris Gray) wrote: > [Felix C:] > > :What follows is a description of something I am currently implementing > :for my server. I am providing it here for others to comment on. Also, > :I'd like to hear of other approaches to the same problem. > > In general, I think such a facility is a very good idea. That's why I have > one in my system! I've found it to be useful in a couple of places, such > as "sublanguages" for my online building commands, etc. > > One of my main concerns, however, is efficiency. LPC isn't as fast as > native code for string handling, so anything you do on a per-character > basis is going to be expensive. In my system, I did a number of builtin > (native) functions to perform most of the core of the work. You can > probably do that too. I am writing the entire function as a server builtin, using lazy DFA construction, lazy DPDA construction, with the appropriate amount of caching between calls, etc. >[...] > Some other issues I've bumped into relating to this kind of parsing: >[...] > - the resolution of a noun-phrase string to a MUD-world object can be > context dependent on the verb in the command. E.g. 'pick up the rock' > can resolve to a different rock than 'take the rock from the sack'. > I handle this by not doing the resolution until I am inside the code > for the specific verb. Perhaps you could pass the verb to your > 'find_obj' and 'find_liv' routines, but that doesn't result in very > modular verbs. In this case, `find_obj' should not just deal with "the rock", but with "the rock from the sack" as a single object. I.e. it's a matter of adjusting the grammar. > My current system is less like your proposal than an earlier one I did. > I don't quite remember why I changed! I do recall, however, that I ended > up with a *lot* of rules in the grammar, to handle the various ways that > the player could give a command. I didn't do the lexical stuff, just the > syntactic level. The lexical stuff was hard-coded. Even if you don't remember <why> you changed, do you remember <what> you changed? :) > In your last "give sword to dwarf" example, what would parse_string return > if find_obj couldn't find a sword? An array containing the words of the > noun-phrase, so that higher-level code could properly complain about not > being able to find a sword? My example does not really deal with this possibility at all. It could be extended in several ways: - the function could return such an array, if the object was not found. - the function could return 0 indicating that this parsing is invalid; this could be combined with an additional grammar rule that functions as a catch-all for errors in the input. - assuming that the grammar is unambiguous, the function could deliver feedback to the user at parsing time. Felix Croes </PRE> <!--X-Body-of-Message-End--> <!--X-MsgBody-End--> <!--X-Follow-Ups--> <HR> <ul compact><li><strong>Follow-Ups</strong>: <ul> <li><strong><A NAME="00180" HREF="msg00180.html">Re: [MUD-Dev] string parsing</A></strong> <ul compact><li><em>From:</em> "Jon A. Lambert" <jlsysinc#ix,netcom.com></li></ul> </UL></LI></UL> <!--X-Follow-Ups-End--> <!--X-References--> <!--X-References-End--> <!--X-BotPNI--> <UL> <LI>Prev by Date: <STRONG><A HREF="msg00176.html">Re: [MUD-Dev] string parsing</A></STRONG> </LI> <LI>Next by Date: <STRONG><A HREF="msg00178.html">Re: [MUD-Dev] string parsing</A></STRONG> </LI> <LI>Prev by thread: <STRONG><A HREF="msg00181.html">Skill Listing - Part I</A></STRONG> </LI> <LI>Next by thread: <STRONG><A HREF="msg00180.html">Re: [MUD-Dev] string parsing</A></STRONG> </LI> <LI>Index(es): <UL> <LI><A HREF="index.html#00177"><STRONG>Date</STRONG></A></LI> <LI><A HREF="thread.html#00177"><STRONG>Thread</STRONG></A></LI> </UL> </LI> </UL> <!--X-BotPNI-End--> <!--X-User-Footer--> <!--X-User-Footer-End--> <ul><li>Thread context: <BLOCKQUOTE><UL> <LI><strong><A NAME="00186" HREF="msg00186.html">Poison List - Part I</A></strong>, Jon A. Lambert <a href="mailto:jlsysinc#ix,netcom.com">jlsysinc#ix,netcom.com</a>, Fri 31 Oct 1997, 05:30 GMT <LI><strong><A NAME="00182" HREF="msg00182.html">Skill Listing - Part II</A></strong>, Jon A. Lambert <a href="mailto:jlsysinc#ix,netcom.com">jlsysinc#ix,netcom.com</a>, Fri 31 Oct 1997, 04:23 GMT <UL> <LI><strong><A NAME="00190" HREF="msg00190.html">Re: [MUD-Dev] Skill Listing - Part II</A></strong>, Derrick Jones <a href="mailto:gunther#online1,magnus1.com">gunther#online1,magnus1.com</a>, Fri 31 Oct 1997, 07:23 GMT </LI> </UL> </LI> <LI><strong><A NAME="00181" HREF="msg00181.html">Skill Listing - Part I</A></strong>, Jon A. Lambert <a href="mailto:jlsysinc#ix,netcom.com">jlsysinc#ix,netcom.com</a>, Fri 31 Oct 1997, 04:20 GMT <LI><strong><A NAME="00177" HREF="msg00177.html">Re: [MUD-Dev] string parsing</A></strong>, Felix A. Croes <a href="mailto:felix#xs1,simplex.nl">felix#xs1,simplex.nl</a>, Thu 30 Oct 1997, 18:44 GMT <UL> <LI><strong><A NAME="00180" HREF="msg00180.html">Re: [MUD-Dev] string parsing</A></strong>, Jon A. Lambert <a href="mailto:jlsysinc#ix,netcom.com">jlsysinc#ix,netcom.com</a>, Fri 31 Oct 1997, 01:17 GMT </LI> </UL> <UL> <li><Possible follow-up(s)><br> <LI><strong><A NAME="00187" HREF="msg00187.html">Re: [MUD-Dev] string parsing</A></strong>, Chris Gray <a href="mailto:cg#ami-cg,GraySage.Edmonton.AB.CA">cg#ami-cg,GraySage.Edmonton.AB.CA</a>, Fri 31 Oct 1997, 07:02 GMT </LI> <LI><strong><A NAME="00192" HREF="msg00192.html">Re: [MUD-Dev] string parsing</A></strong>, Felix A. Croes <a href="mailto:felix#xs1,simplex.nl">felix#xs1,simplex.nl</a>, Fri 31 Oct 1997, 12:12 GMT </LI> <LI><strong><A NAME="00193" HREF="msg00193.html">Re: [MUD-Dev] string parsing</A></strong>, Felix A. Croes <a href="mailto:felix#xs1,simplex.nl">felix#xs1,simplex.nl</a>, Fri 31 Oct 1997, 20:06 GMT </LI> </UL> </LI> </UL></BLOCKQUOTE> </ul> <hr> <center> [ <a href="../">Other Periods</a> | <a href="../../">Other mailing lists</a> | <a href="/search.php3">Search</a> ] </center> <hr> </body> </html>