Path: csiph.com!usenet.pasdenom.info!aioe.org!.POSTED!not-for-mail From: "Rod Pemberton" Newsgroups: comp.lang.forth Subject: Re: CASE mis-understanding? Date: Sun, 16 Feb 2014 07:46:28 -0500 Organization: Aioe.org NNTP Server Lines: 61 Message-ID: References: <52e7b833$0$24947$e4fe514c@dreader36.news.xs4all.nl> <52e7c363$0$24916$e4fe514c@dreader36.news.xs4all.nl> <66e2b3ae-f7c4-494a-bf1b-0a710763d8f2@googlegroups.com> <2b99e79c-6aef-402c-8667-322d3f24509e@googlegroups.com> <6bced7b9-403d-489d-bb7e-92b481249d1b@googlegroups.com> <1193tk4cxc2yq.1382doevi4pif.dlg@40tude.net> <49ef5d79-6888-4918-bdbf-3b0f0641fff9@googlegroups.com> <7a1bded8-8d24-4ea1-acf2-afaf912181a3@googlegroups.com> <302fb35a-1bfe-40fb-ae2e-b237a8db9bdd@googlegroups.com> NNTP-Posting-Host: CNsg4fVcCsvs3UaOgZtQCw.user.speranza.aioe.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit X-Complaints-To: abuse@aioe.org User-Agent: Opera Mail/12.16 (Linux) X-Notice: Filtered by postfilter v. 0.8.2 Xref: csiph.com comp.lang.forth:28483 On Sat, 15 Feb 2014 19:52:21 -0500, wrote: > I didn't bother responding to Rod's post previously, because it is all > nonsense --- it is not possible to have the control-stack be the same as > the return-stack. Is isn't *possible*? ... You can't return from a Forth word in the middle of existing control-flow. The control-flow sequence must be completed first. (This is where an understanding of structured code, especially in C, would help you.) Therefore, there is no conflict. I.e., it is *possible* to use the return-stack as the control-flow stack. It would seem to me that a conflict issue between control-flow and user data on the data stack is more likely. The user uses the data stack far more frequently than the return-stack. The only real issue with using the return-stack for control-flow is that data must be moved to it from the data stack and back. > The ANS-Forth document (3.2.3.2.) says that the > control-stack may or may not be the same as the data stack. ... > Rod doesn't really know anything about Forth --- total ignorance is > demonstrated in statements such as: "If the control-flow stuff is on > the return-stack, 'it doesn't conflict with the user's data on the > data-stack.' " How would it conflict? > Elizabeth Rather is apparently okay with responding to nonsense, or just > doesn't recognize nonsense because she doesn't know any more about Forth > than Rod does (all she knows is what is in "Starting Forth"). I've implemented a Forth interpreter in C at first, now mostly in Forth. So, I know far more than many Forth people do about Forth. Of course, there are people who are far better versed at this than I am. Admittedly, I'm not fond of the language or experienced much in it, other than implementing the Forth system words in Forth. But, coding them is still coding quite a bit of Forth ... Much of it was coded from scratch, some from existing common definitions, some the result of Forth optimizers, and some of it converted to Forth from Forth in C, and also from C not remotely expressed as anything like Forth. It seems unlikely to me that there are more than a few people around here who can convert C to Forth, or the reverse, as I demonstrated in a reply to Julian Noble many years ago. I'm not saying my interpreter is perfect. All I know is that it seems to work correctly (when I don't mess things up). It passes the tests I coded. It passes Hayes core for the words that are implemented. ANS compliance wasn't even attempted ... It is mainly fig-Forth based. Now, you can attribute that to my skill, or perhaps to the excellence of the Forth standards ... Either way, things are (mostly) working as expected. It's not a completed project, yet. Rod Pemberton