World: r3wp
[Parse] Discussion of PARSE dialect
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Pekr 15-Sep-2010 [5202] | and - it was not nitpicking on your part - using the correct terminology where possible is important, as it helps to correctly interpret the way in which the language works. It is just lack of knowledge on my part, that I confuse the terms ... exactly because I often don't understand the internals ... |
Izkata 15-Sep-2010 [5203] | start: :end and temp: would just be called set-words and get-words, either within the Parse dialect or the Do dialect (Do dialect being "rebol level") |
Anton 15-Sep-2010 [5204] | To be even more precise; The 'copy word above is also a "regular" rebol word (it just happens, additionally, to be interpreted by PARSE as a keyword in the PARSE dialect). |
Ladislav 15-Sep-2010 [5205] | Re start: and :start e.g. - they are values of different datatypes, but can be seen as just one variable. |
Ladislav 16-Sep-2010 [5206] | http://www.rebol.org/view-script.r?script=use-rule.rupdated. Changes: now it implements both USE-RULE variants as described in http://www.rebol.net/wiki/Parse_Project . |
Ladislav 18-Sep-2010 [5207x6] | Hi, I rewrote http://www.fm.tul.cz/~ladislav/rebol/evaluate.rto contain slightly more comments and to use the USE-RULE function, so that it now became a more complex example of its usage. |
I hope everyone struggling with local variables in PARSE to find this a much more comfortable way. | |
On the other hand, I expect the %evaluate.r to have a value of its own, since it shows how to handle expressions using PARSE, while being able to respect different priority/associativity rules sets. | |
The funny thing about it is, that just one local variable per parse rule was quite sufficient in this case, although the example isn't trivial in my opinion. | |
http://en.wikibooks.org/wiki/REBOL_Programming/Language_Features/Parse#Local_variables_in_parse_rules , a new subsection in the REBOL Programming wikibook. | |
http://en.wikibooks.org/wiki/REBOL_Programming/Language_Features/Parse#Local_variables_in_parse_rules a new section in the REBOL Programming wikibook | |
Janko 18-Sep-2010 [5213] | wowo, most awesome Ladislav! |
Ladislav 18-Sep-2010 [5214x2] | Pekr, knowing that you were interested in the subject as well, I sincerely hope, that you read the wikibook subsection, run the examples, and let me know what you are missing in the doc and in the functionality. |
thanks, Janko | |
Claude 20-Sep-2010 [5216x4] | hi, i would you to parse a string like this {number: 123456 name: abcd message: i like rebol} |
i would like to use parse to do it | |
something like this way parse mystring ["number:" number: "name:" name: "message:" msg:]] | |
a get number, name and msg . is that possible ? and how ? | |
Maxim 20-Sep-2010 [5220] | is the data guaranteed to be rebol compatible? (you can use 'LOAD on it and it will never return an erro) |
Claude 20-Sep-2010 [5221x3] | but mystring is like this {Number : 10017 Name : Disable Message Partner Application: MXS Severity : Info Type : Alarm Event Date-Time : 20/09/10 12:39:43 GMT : Mon Sep 20 10:39:43 2010} |
i start to use => parse mystring [thru "Number :" number: to end] | |
i would like to do => parse mystring [thru "Number :" number: to "Name :" ] but this don't work !!!!] | |
Maxim 20-Sep-2010 [5224x4] | using 'TO or THRU rules is garanteed to make you life a nightmare for arbitrary string parsing, unless its very linear in content. |
isn't there a rebol string parser on rebol.org which has the basic parsing rules to filter out rebol data? | |
with a few search I didn't zero-in on it, but I seem to recall seeing that before. | |
otherwise, you can just do a line by line parsing, filtering out "keywords" at the start and then loading the data after the ":" | |
Claude 20-Sep-2010 [5228x2] | if i can't use parse i will do this |
but it is very strange. i heard that parse is very powerfull. and now i can't use it because if to difficult !!!! | |
Maxim 20-Sep-2010 [5230] | parse is very powerfull and easy to *use* but *mastering* it isn't. |
Janko 20-Sep-2010 [5231] | [thru "Number :" copy number [ to newline | to end ] ] maybe? |
Maxim 20-Sep-2010 [5232x2] | although it is much more approachable than regexp in certain ways. |
here is an overblown example, with lots of extra prints, so you can see it running... it parses your above example text. -------------------------------- rebol [] data: {Number : 10017 Name : Disable Message Partner Application: MXS Severity : Info Type : Alarm Event Date-Time : 20/09/10 12:39:43 GMT : Mon Sep 20 10:39:43 2010} ; rules token: ["Number" | "Name" | "Severity" | "Type" | "Date-Time" | "GMT" | "Application"] space: charset " ^-" spaces: [any space] content: complement charset "^/" ; all but newlines. contents: [some content] ; used as variables in the rules v-token: none v-content: none parse/all data [ some [ ( print "^/0>" ) copy v-token token ( print "1>" probe v-token ) spaces ; ignore ( print "2>" ) ":" ; end of token ( print "3>" ) spaces ; ignore ( print "4>" ) copy v-content contents ;grab all but newline ( print "5>" probe v-content ) [ ; this is important, it ensures that you've got a whole line. [some "^/"] | end ] ( print "6>" ) ( ; do something with your data here ?? v-token ?? v-content ) ] ] probe "." ask "done" | |
Claude 20-Sep-2010 [5234] | thank you i will test it and try to understand too ;-) |
Maxim 20-Sep-2010 [5235] | I made it easy for you to figure out (at least as easy as can be ;-) |
Claude 20-Sep-2010 [5236x2] | Maxim here the result |
0> 1> Number 2> . done | |
Maxim 20-Sep-2010 [5238] | using which rebol? I did run it through and it worked ok on 2.7.7 |
Claude 20-Sep-2010 [5239x2] | it stop at ":" !!! |
2.7.7.4.2 | |
Steeve 20-Sep-2010 [5241] | Much easier with R3. assuming, >> src: {Number : 10017 Name : Disable Message Partner Application: MXS Severity : Info Type : Alarm Event Date-Time : 20/09/10 12:39:43 GMT : Mon Sep 20 10:39:43 2010} then, >> construct parse copy src [return while[and[some #" " #":"] remove[some #" "]| skip]] == make object! [ Number: "10017" Name: "Disable Message Partner" Application: "MXS" Severity: "Info" Type: "Alarm Event" Date-Time: "20/09/10 12:39:43" GMT: "Mon Sep 20 10:39:43 2010" ] |
Claude 20-Sep-2010 [5242x2] | thank you steeve but i need it for a production server to parse log file for nagios |
i would prefer to use rebol 2 | |
Maxim 20-Sep-2010 [5244x4] | claude it might be because of copy/pasting... you are on linux.. did you just copy the code and paste it into the console? |
the best is to copy it to a file and run it. | |
I just (re)tried it and it does work on my system... | |
(windows xp box) | |
Claude 20-Sep-2010 [5248] | well i on linux and on linux altme do work well with ctrl-c !!!!! |
Maxim 20-Sep-2010 [5249x2] | but here we are parsing and any character code has to be loaded properly.. in theory it should work.. but it seems not... add this just before the ":" here: (probe copy/part here 20) it will print what is exactly at that point ... may provide clues as to why the ":" isn't matching... |
note: I just tried to copy/paste the above in my R2 console .. it worked ok.. | |
Claude 20-Sep-2010 [5251] | 0> 1> Number 2> : 10017^/Name . done |
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