Path: utzoo!utgpu!watserv1!watmath!att!att!pacbell.com!ucsd!usc!zaphod.mps.ohio-state.edu!lavaca.uh.edu!menudo.uh.edu!sugar!ficc!peter From: peter@ficc.ferranti.com (Peter da Silva) Newsgroups: comp.lang.misc Subject: Re: Re^6: Some things that pointer-less languages can't do efficiently Message-ID: <35S67X@xds13.ferranti.com> Date: 30 Oct 90 21:06:40 GMT References: <26739:Oct1023:44:2690@kramden.acf.nyu.edu> <65450@lanl.gov> <420@data.UUCP> <422@data.UUCP> Reply-To: peter@ficc.ferranti.com (Peter da Silva) Organization: Xenix Support, FICC Lines: 57 In article <422@data.UUCP> kend@data.UUCP (Ken Dickey) writes: > The definition of "pointer" comes from an extensive body of literature > on computation. You should use a term with a meaning closer to what > you wish to express rather than redefining a term with an established > meaning. CS is already full of overdefined terms. Fine. You want to play name games. THe question at hand is "what is a pointer", or "what is it that makes pointers dangerous". To answer this question you have to ask "what is a pointer" in terms of what we want to know about them. If you think the fact that a pointer points at a machine address (an implementation detail) is significant, then is Sabre-C a pointerless language? If so, what is significantly different between it and conventional C implementations? > In the context of computer programming languages, "token" has a > meaning in the context of syntax. I did not know you were speaking of > networks. What is the meaning of "pointer" in the context of network? No, the term "token" has a meaning in the larger world of CS: a token is an opaque object that refers to another object. In the context of compilers it's a small easily-handled object that refers to a string of characters. In the context of a network it's a logical object that's passed between machines on the network to indicate which machine has the right to pass a message on. (in the context of a network, I guess "xds13.ferranti.com" is a pointer) > I am arguing whether "pointers" are available as a source language > concept. So am I. Warning... skip the next few exchanges if quibbles about irrelevent analogies bore you. > If I have a "house", it is defined in terms of roof, walls, > etc. I speak of being in a particular room, etc. A house may be (but > does not have to be) constructed partially from "boards". I do not > talk about going from room to room in a house by speaking about > boards. Fine, but for some reason you're denying that an apartment is a house because it doesn't have 4 walls of its own. > Boards are not a "house-level" concept. Why do you insist on > redefining board to be a unit of room traversal? You're completely misinterpreting me if you think that. I don't care what the underlying implementation does. It doesn't have to have machine addresses in the implementation anywhere... look at the UNIX file system: a link (either symbolic or hard) is a pointer, but there are no CPU addresses involved at all. Hell, a symbolic link can point into another address space! > [Seriously, let's take the language bashing off-line] Huh? Who's language-bashing? -- Peter da Silva. `-_-' +1 713 274 5180. 'U` peter@ferranti.com