World: r3wp
[Parse] Discussion of PARSE dialect
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Maxim 12-Oct-2009 [4469] | yeah, maybe its just really hard to implement based on the parse algorythm... so not worth the time to implement. |
BrianH 12-Oct-2009 [4470] | Plus, it makes the code flow really tricky to understand. You aren't doing your later maintainer of your code any favors (even if it's you). |
Pekr 12-Oct-2009 [4471] | I am not sure why "to end" attempted several times does not fail? Simply put - if you put any rule, it consumes the input, so I would expect, that once at the end of th input = the rule was matches, second call of "to end" should fail, no? It does not correspond to "to "abc"", which called consecutively would try to find ANOTHER match for "abc", not just the same. I don't see a reason, why "to end" should have an exception. It should imo definitely cause termination. |
BrianH 12-Oct-2009 [4472x3] | Because you can't through the end, not even with THRU END. And once you reach the end, END always succeeds. |
And TO "abc" will also continue to succeed, matching the same "abc" every time. THRU "abc" skips past the "abc" like you say. | |
you can't -> you can't go | |
Pekr 13-Oct-2009 [4475] | Are parse enhancements over, or do we get some other? |
BrianH 13-Oct-2009 [4476] | Well, a89 isn't out yet (when last I checked). Beyond that, it depends on how Carl reacts to the recent blog on the parse plans. |
Pekr 13-Oct-2009 [4477] | So according to his doc, we should get BREAK/RETURN and DO? |
BrianH 13-Oct-2009 [4478] | We don't need BREAK/return anymore, but he can reuse the code he used to implement the RETURN paren operation. I hope we get DO, but Carl was iffy since few were puushing for it. Gabriele's been silent, which is weird since it was his idea. |
Pekr 13-Oct-2009 [4479x2] | Carl should not judge upon his own usage of some features ... |
But generally - the level of feedback is lower and lower. We need to get R3 into beta with requested features in few months, as we are starting to loose ppl being interested ... | |
BrianH 13-Oct-2009 [4481x2] | Um, yeah, but he should about OF (as ALL). What he wanted to do with OF was important. |
The level of feedback? It's been a discussion. When it comes to PARSE, the discussion has pretty-much resolved itself., | |
Pekr 13-Oct-2009 [4483] | Yes, that one might be missed. Dunno why he wants to remove it. Also LIMIT would be nice to have ... |
BrianH 13-Oct-2009 [4484] | He is wary of adding it because he knows how difficult it would be to implement it. LIMIT too :( |
Pekr 13-Oct-2009 [4485x2] | well, otoh we lived without OF for so long. I think it can be done in a conventional (recent) way :-) I think that Carl should dedicate few more days to finish parse and move on to Extensions :-) |
... because that is the way to release host code ... | |
BrianH 13-Oct-2009 [4487x4] | The conventional way has exponential overhead. |
All PARSE needs is a few final decisions. I expect that it won't be too difficult to do the rest, at least the rest that won't be put off. | |
The DO operation was proposed 5 years ago, before R3's change in the behavior of DO/next. The new DO/next is much better suited to the parse workarounds than the old DO/next was. We can thus do without the DO operation if need be. | |
The BREAK/return proposal was proposed before Carl added the RETURN paren option, which makes BREAK/return unnecessary. | |
Pekr 13-Oct-2009 [4491] | OK, so we are almost done with parse, right? (As I don't expect Carl changing his mind about the deferred proposals, at least not for 3.0) |
BrianH 13-Oct-2009 [4492] | The only still-missing proposals that aren't easy or efficient to work around are OF and REVERSE. They will be missed if not included. Unfortunately, the same reasons why they will be hard to work arond if missing, are the reasons why they would be difficult to implement :( |
Pekr 13-Oct-2009 [4493] | btw - what is the outcome of so called - complementing? Will we get it enhanced, so that we can use it even with Unicode? I noticed Carl said that complements could be enhanced .... |
BrianH 13-Oct-2009 [4494x2] | I expect that PARSE release features will be done in a89 - the rest will be bug fixes. |
One of the bitset! bugs was fixed in a88, but complementing is yet to come. It will probably be the using a bit for a flag method. | |
Pekr 13-Oct-2009 [4496] | Shouldn't be such enhancement part of the proposal doc? (just in order to have it documented :-) |
BrianH 13-Oct-2009 [4497] | Yes, it should. Care to add it? |
Pekr 13-Oct-2009 [4498] | I can add it, just not sure I would describe it precisely :-) |
Pekr 14-Oct-2009 [4499] | Carl asks about the usability of Until proposal - if not answered/defined, it will not be part of 3.0 - http://www.rebol.net/r3blogs/0271.html |
BrianH 14-Oct-2009 [4500] | Did an initial answer, but Ladislav really needs to expand on it. |
Pekr 14-Oct-2009 [4501x3] | hmmm ....http://www.rebol.net/r3blogs/0272.html |
Interesting how Carl asks for naming convention opinion, there was no single vote for 'loop, yet such word was chosen ;-) http://www.rebol.net/r3blogs/0273.html | |
We have one hour to decide, if we want 'loop being renamed to 'while .... | |
Graham 14-Oct-2009 [4504] | Tim Berners-Lee is quoted today to say that he can't think of a good reason to keep the // in http://, and that if he did it again, he would have done without them. I wonder if he spoke to people who write parsers .... |
Gabriele 15-Oct-2009 [4505x2] | the reason for the // is to allow relative paths like: //www.rebol.com/ where the scheme is the same as the base url. Nobody has ever used this; also, it could have been achieved by using :www.rebol.com/ instead... so, yeah, it was not really a good idea. I also don't think ftp:file.txt (meaning, change scheme, but keep host and path) has ever been used and not sure it's supported by software. so in practice http:www.rebol.com/ would have worked. |
it has to be said, that the www subdomain is also a silly habit. | |
Pekr 15-Oct-2009 [4507] | As for parse docs - why is 'then not being among the keywords? Isn't it a keyword? |
BrianH 15-Oct-2009 [4508] | It's an operator, like |, and mentioned in that section near the top. |
Pekr 15-Oct-2009 [4509] | isn't AND operator too for e.g.? |
Chris 17-Oct-2009 [4510] | First pass at converting my AltXML to R3: http://www.ross-gill.com/r/r3xml.r -- almost a literal translation, doesn't yet utilise new parse features... |
Pekr 17-Oct-2009 [4511x2] | The DO keyword was added to A91 - Gabriele should be happy now :-) http://www.rebol.net/r3blogs/0276.html |
http://www.rebol.net/r3blogs/0277.html- Trouble renaming BREAK to ACCEPT in following case: some [break | "b"] .... where it returns FALSE. Carl seems to suggest, that unless that case is solved, it can't be renamed ... | |
Maxim 17-Oct-2009 [4513] | gave my two cents on the blog... hehehe |
Pekr 17-Oct-2009 [4514] | Max - we are close to finish parse. It is clear Carl will move to other priorities. Sorry to hunt you here or there, but any chance you get your Extensions short doc done? No doc = no callback probably :-) |
Maxim 17-Oct-2009 [4515] | I really want to do it... but I'm so deep into parsing right now I don't want to loose the few GB of information in my brain's cache. I'm writing self-modifying parse rules and its pretty nightmarish. although it works. |
Gabriele 17-Oct-2009 [4516] | Ah, 6 years of wait finally over. Now, if we could get those changes ported to R2... |
Maxim 17-Oct-2009 [4517] | hehehe you finally got your DO ;-) |
Henrik 17-Oct-2009 [4518] | Do we have a list of PARSE changes that are no longer compatible with R2? I think that would be important in porting parse scripts from R2 to R3. |
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