Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!hc!lanl!opus!ted From: ted@nmsu.edu (Ted Dunning) Newsgroups: comp.lang.prolog Subject: Re: ProYACC??? (was: Pro4th???) Message-ID: Date: 26 Jul 89 17:27:38 GMT References: <12746@well.UUCP> <3526@csd4.milw.wisc.edu> Sender: news@nmsu.edu Organization: NMSU Computer Science Lines: 55 In-reply-to: markh@csd4.milw.wisc.edu's message of 25 Jul 89 23:43:20 GMT In article <3526@csd4.milw.wisc.edu> markh@csd4.milw.wisc.edu (Mark William Hopkins) writes: Path: opus!lanl!hc!ames!mailrus!csd4.milw.wisc.edu!markh From: markh@csd4.milw.wisc.edu (Mark William Hopkins) Newsgroups: comp.lang.prolog Keywords: forth, forlog, foobar Date: 25 Jul 89 23:43:20 GMT References: <12746@well.UUCP> Sender: news@csd4.milw.wisc.edu Reply-To: markh@csd4.milw.wisc.edu (Mark William Hopkins) Organization: University of Wisconsin-Milwaukee Lines: 29 ... about writing a forth in prolog Yes it could! Here's an outline: (1) Set up a LR(1) parser generator in Prolog. (2) Create a YACC-like front end, using Prolog's existing grammar notation and your parser generator. (3) Write a Forth compiler using the YACC-like parser generator (choose your favorite target language for efficiency) (4) Use the compiler to compile the said Forth program into the target language and (5) Run the executable code. ... more drivel. this posting demonstrates lamentable ignorance of both prolog and forth. in particular, 1) lr(1) parser generators don't have much more power than the currently ubiquitous dcg systems. the only real disadvantage of lr(1) is the ability to use left-recursion. 2) forth doesn't even have a real parser or compiler, just a tokenizer that directly dispatches to the definition of each word. the compilation is generally done by directly threading code, but occasionally an compiler word actually does something very minor like depositing the address of a literal handler into the code stream. 3) simulating forth which a list for the stack is going to abominably slow. we are talking 2 or more orders of magnitude disadvantage. i don't want to discourage posters in general, but please check with the real world before you post. -- ted@nmsu.edu This is the most beatiful place in the world. Edward Abbey, Desert Solitaire