World: r3wp
[Parse] Discussion of PARSE dialect
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Maxim 16-Jun-2009 [3920] | yes it goes one past the end. it does not stop AT the end. |
BrianH 16-Jun-2009 [3921] | end has no length, so to end and thru end mean the same thing. |
PeterWood 16-Jun-2009 [3922] | I guess you could answer that end is past the end of the input. But the behavior seems inconsistent: >> parse "123456789" [thru "8" "9" end ] == true >> parse "123456789" [thru "9" end] == true >> parse "123456789" [thru end] == false |
Maxim 16-Jun-2009 [3923] | but brian, skipping past the end, still puts you at the end of the series, but the parser know you tried to go beyond the end... ITs the thru wich is failing, cause it knows you are trying to go beyond the end. |
PeterWood 16-Jun-2009 [3924] | It's different in R3 :-) >> parse "123456789" [thru end] == true |
Maxim 16-Jun-2009 [3925] | thru consumes the end word, and then detects that, as a result, it would put you beyond the end. really, its quite logical. but in practically, thru shouldn't complain.... cause as you say, in this specific context, thru and to really do mean the same end. |
PeterWood 16-Jun-2009 [3926] | I prefer the R3 behaviour. I really hope that it doesn't change. |
BrianH 16-Jun-2009 [3927] | I'll make sure of that, Peter. |
PeterWood 16-Jun-2009 [3928] | Thanks. |
Ladislav 16-Jun-2009 [3929] | yes, Peter, I am sure R3 behaviour is correct |
BrianH 23-Jun-2009 [3930x2] | In R2: >> parse/all { X X XX X X} [(prin 'a) some [(prin 'b) "X" (prin 'c) [(prin 'd) "X" (prin 'e) | (prin 'f) skip (prin 'g)] (prin 'h) | (prin 'i) skip (prin 'j)] (prin 'k)] abijbcdfghbcdfghbijbcdehbijbcdfghbcdfijbik== true In R3: >> parse/all { X X XX X X} [(prin 'a) some [(prin 'b) "X" (prin 'c) [(prin 'd) "X" (prin 'e) | (prin 'f) skip (prin 'g)] (prin 'h) | (prin 'i) skip (prin 'j)] (prin 'k)] abijbcdfghbcdfghbijbcdehbijbcdfghbcdfijk== true In both cases the fij near the end should should be fgh - a bug in PARSE. |
Never mind, I missed that the last X is at the end of the string. No bugs. | |
shadwolf 30-Jun-2009 [3932x2] | the more i try to understand parse the less i understand it |
i want to try to make a tutorial about parse but my knowledge of it is poor so as we have a wiki we could start a project to write a documentation with the goal to make people understand what is the interrest of parse | |
Sunanda 30-Jun-2009 [3934] | Parse question on stackoverflow (unanswered as yet:) http://stackoverflow.com/questions/1060727/rebol-parse-dealing-with-whitespace-and-copy-var |
BrianH 30-Jun-2009 [3935] | Answered :) |
Sunanda 30-Jun-2009 [3936] | Fast! |
shadwolf 30-Jun-2009 [3937] | http://www.rebolfrance.info/articles/allaboutparse documentation to put all what we want to now about parse |
BrianH 30-Jun-2009 [3938] | There's also a lot of documentation about parse's behavior (in theory) at the beginning of the Parse Proposals page on DocBase. |
shadwolf 30-Jun-2009 [3939] | BrianH yea but that's really too light you can't expect people gaining Guru level in parse with so poor documentation ... I want to know all about parse and i want that knowledge to be sahred |
BrianH 30-Jun-2009 [3940x2] | Alas, to know all about parse you have to go to the guru level. To know enough to get by, you don't :) |
Code like that example above with all the (prin) calls can help a lot wiith understanding parse though. | |
Sunanda 30-Jun-2009 [3942] | What would be useful would be a parse cookbook.....HowTo questions with sample answers. That way, we could build up a set of carefully graded examples of putting parse to work. |
shadwolf 30-Jun-2009 [3943x4] | sunanda that's what i have in mind |
but not only ... | |
first you give the basic you say what is parse you eplain how you can use it and then for the very hl part of the documentation you have examples working or not and answers from gurus explaining what you missed in your implementation | |
sunanda look the page i submited if you have any comments | |
Maxim 30-Jun-2009 [3947] | parse is a part of rebol which needs a complete book to be written about it. To go from zero to hero it could easily span 100 or more pages. |
shadwolf 30-Jun-2009 [3948] | Maxim i agree lets do it :P |
Maxim 30-Jun-2009 [3949] | to me parse is something that is useless until you understand it.... at which point, you are a guru. There is no real middle ground, which is the problem. |
shadwolf 30-Jun-2009 [3950] | but really i have a thousand projects in mind and i'm locked because of my parse low knowlege i can add things to existing parse rules but building a rule or a dialect from scratch is impossible for me |
Pekr 30-Jun-2009 [3951x2] | parse just needs to implement suggested refinements to make it more easy to use ... |
I am able to parse what I need, am far from guru, but I still find parse usefull. I would not be able to write single regexp line .... | |
shadwolf 30-Jun-2009 [3953] | Maxim if people will know how to explain parse in ten years of existance it will be done already but nothing goes against trying and in the end the result can be surprising |
BrianH 30-Jun-2009 [3954] | One of the best ways to learn is to try to figure out enough to teach others :) |
shadwolf 30-Jun-2009 [3955x7] | Pekr if you saw viva-rebol code you could see parse will be usefull for the function click and go part instead of the weak actual solution base on either any [ find ...] ] |
as area-tc is base on parse to draw on screen having a better understanding of parse would lead to the creation of a all purpose ritch text rendering widget using an adapated dialect | |
but i'm amased some years ago rebol was all about eep computing simple by creating dialects addapted to your needs. But in reality parse is so compexe that this aspect of rebol is from far one of the less used .... | |
and in my opinion we are missing really something ... That's the kind of thing carl found so easy to use that he never though about creating a complete documentaton on it | |
at least that's my opinion ... I always delayed this kind of project I was expecting someone to do it But time passed and no complete documentation emerged. | |
i started writing the documentation and organising the plan of the document and how i see things organised. all comments or adding to this document are welcome. | |
I recall the URL: http://www.rebolfrance.info/articles/allaboutparse | |
Graham 30-Jun-2009 [3962] | there is a section on parse in the wikibook .. you could add to that... |
shadwolf 30-Jun-2009 [3963x7] | graham .. wiki is for R3 since R2 and R3 are not the same it's better to not mix them. We can build the documentation prototype on french wiki and then upload it with adaptations to unicode and other R3 parse new things... to R3 wiki. I prefere using french wiki because it's wide open no need to fill a form and log to be granted as a reader and in my mind this have to be the most open wide possible. |
as a writer lol ofcourse ... | |
but yes that will be a need to be on wiki R3 .. but before talking on what is not official can we talk about what is official and already wait for us to use it since so many years ? | |
graham even if from taht wor then you write a book on parse and become billionare I won't be annoyed by that hahaha (if that's the case I and the other writers would gladly appreciate you to send us a plane to ticket to visit you graham :P) | |
any people that want to explain what he understoud from parse should be able to write it somewhere and have other people contribute to it well in my particular case that will end fast lol i'm not a parse guru i'm just a rebol coder willing to understand parse and use it the more often possible in all my projects. | |
i recognise i have been lazy and skipping the pain to understand parse too much time... | |
we can live without parse yes .... but then we have post from Carl saying that the rebol community is coding in rebol like they could code in any other language and skippping the most part of interrest of coding in rebol... and yes i'm not against that remark that's completly true. what interrest me is how can we promote the use of parse and how can we give back to parse use and dialects conception the central place they deserve ? | |
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