World: r3wp
[Parse] Discussion of PARSE dialect
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Pekr 19-Jul-2006 [1376x2] | I now can create simply a func, which will accept mark name, and do some code-block accordingly - sql query, simple replace of value, whatever (well, it will not work for cases like img tags, so it is not as flexible as full html parser in temple for e.g., but hey, it is meant being simple) |
... but should not be simpler, so I wonder - so far, as you can see, mark-x is not finished, so it is ignored. How to catch this case properly and eventually generate error, send email, write to log, whatever? | |
Anton 19-Jul-2006 [1378x2] | I did that recently for COMLib. Look for build-comlib-website.r in the files section of the COMLib website. |
(my end tags are simpler though) | |
Pekr 19-Jul-2006 [1380x2] | ok, will look into. Is that much complicated than mine is? :-) |
this one works better for me: parse/all template [ some [ thru "<!--[" copy mark to "]-->" "]-->" start: copy text to "<!--/[" end: "<!--/[" [mark "]-->" (print text) | (print ["not found end of: " mark]) :start] | skip ] ] | |
Maarten 19-Jul-2006 [1382] | Petr.... you just reinvented erebol, rsp, .... build-markup? |
Volker 19-Jul-2006 [1383] | But it does the job, as far as i read. |
Pekr 19-Jul-2006 [1384x5] | Maarten - not reinvented - rsp, iirc, mixes code of rebol with html, which I don't want to allow |
template has to be displayable as gfx man does it, with temporary text, images, whatever .... I am just supposed to get correct data in there .... | |
Maarten - now looking into build-markup - sorry, it is just strange was of doing things .... noone will place rebol code into template, that will not work ... btw - the code is 'done? What happens if someone uploads template with its own code? I want presentation and code separation. | |
I looked into rsp some time ago, and I liked it, especially as it was complete, with session support etc., but later on I found shlik.org being unavailable ... | |
Maarten - is RSP still available anywhere for download? erebol.com nor shlik.org do work .... | |
Chris 19-Jul-2006 [1389] | Petr, I have a copy with some notes here: http://www.ross-gill.com/techniques/rsp/ |
Ladislav 31-Aug-2006 [1390] | I think, that Tim Peters knew what he wrote here: http://mail.python.org/pipermail/python-dev/1999-December/001770.html |
JaimeVargas 31-Aug-2006 [1391] | Very nice comments. But comparing a parser with a regex is a bit unfair ;-) |
BrianH 31-Aug-2006 [1392x2] | Yeah, for either :) Still, Peters seems to think that REBOL parse rule blocks are closures, for various reasons that are clear from context. |
They aren't, though something like parse closures has been suggested during the latest round of enhancement proposals. | |
Volker 31-Aug-2006 [1394] | They are quite like smalltalk-closures. Without locals, but locals are not his point. (he may miss them for recursion). |
BrianH 31-Aug-2006 [1395] | Hey, locals and arguments (practically the same thing in REBOL) are the most important difference between closures and plain blocks. The difference is significant but Peters' background with Smalltalk made him miss it - Smalltalk "blocks" look like REBOL blocks but act like functions. |
Volker 31-Aug-2006 [1396x4] | No, the main point is, easy definitions of code and referencing the original context. Rebol-blocks do that. |
You can have closures without any arguments. | |
The highlights he mentions is: lexically-scoped, code and data, freely mix computations in | |
That scoping is the difference between a closure and doing a "string" here. | |
BrianH 31-Aug-2006 [1400] | REBOL blocks don't reference a context, but they may contain words that reference a context. Still, this distinction makes no difference to the argument that Peters was making - REBOL text processing is more powerful than regex and easier to use. It would be easier to replicate REBOL-style parsing in Python using closures and generators anyway (Peters' real subject), since that is the closest Python gets to Icon-style backtracking. |
Volker 31-Aug-2006 [1401x3] | its not important what references the context, but that a variable can find one. |
result := a > b ifTrue:[ 'greater' ] ifFalse:[ 'less' ] | |
There are two closures here. Rebol could do it the same way. | |
Ladislav 31-Aug-2006 [1404] | besides, Tim was a REBOL 1.x user |
Gabriele 1-Sep-2006 [1405] | didn't parse come with 2.0? |
Ladislav 1-Sep-2006 [1406] | it did, so it looks, that Tim is still silently watching REBOL |
Gabriele 2-Sep-2006 [1407] | most probably he didn't leave as soon as we think :) i think i remember him on the list in 2.0 times too. |
Ladislav 2-Sep-2006 [1408] | seems you are right |
Oldes 15-Sep-2006 [1409] | Maybe someone find it usefull: remove-tags: func[html /except allowed-tags /local new x tag name tagchars][ new: make string! length? html tagchars: charset [#"a" - #"z" #"A" - #"Z"] parse/all html [ any [ copy x to {<} copy tag thru {>} ( if not none? x [insert tail new x] if all [ except parse tag ["<" opt #"/" copy name some tagchars to end] find allowed-tags name ][ insert tail new tag ] ) ] copy x to end (if not none? x [insert tail new x]) ] new ] |
Geomol 24-Sep-2006 [1410] | Wouldn't it be nice, if the /case refinement for parse also worked with words, when parsing blocks? >> parse [aBc] ['abc] == true >> parse/case [aBc] ['abc] == true It should work like when parsing strings, I think! >> parse "aBc" ["abc"] == true >> parse/case "aBc" ["abc"] == false |
JaimeVargas 24-Sep-2006 [1411] | Why? words are not case sensitive by definition. |
Geomol 25-Sep-2006 [1412] | I would like the functionality, when parsing things like TeX. There the greek letter gamma is called gamma, and the same in capital is called Gamma. Now I have to invent the word capgamma or something. |
Gabriele 25-Sep-2006 [1413] | >> parse ["Gamma"] ["gamma"] == true >> parse/case ["Gamma"] ["gamma"] == false |
Gregg 25-Sep-2006 [1414] | If it were a safe and easy thing to change, I can see some value in it as an option but, since words--and REBOL--are case insensitive, I'm inclined to live with things as they are, and use string parsing if case sensitivity is needed. I think it's Oldes or Rebolek that sometimes requests the ability to parse non-loadable strings, using percentage values as an example. I think loading percentages would be awesome, but then there are other values we might want to load as well; where do you draw the line? I'm waiting to see what R3 holds with custom datatypes and such. |
Oldes 25-Sep-2006 [1415] | Yes, it's me who is calling to add posibility to load anything what is now throwing invalid datatype error. |
Gregg 25-Sep-2006 [1416x2] | And didn't you suggest that values throwing errors could be coerced to string! or another type? e.g. add an /any refinement to load, and any value in the string that can't be loaded would become a string (or maybe you could say you want them to be tags for easy identification). |
I'm not sure how custom datatype lexing would work, unless it did something similar, calling custom lexers when running up against values the standard lexer doesn't understand. I can't remember how Gabriele's custom type mezz code works either; need to look at that. | |
Oldes 25-Sep-2006 [1418x3] | I think, load/next can be used to handle invalid datatypes now: >> b: {1 2 3 'x' ,} == "1 2 3 'x' ," >> while [v: load/next b not empty? second v][probe v b: v/2] [1 " 2 3 'x' ,"] [2 " 3 'x' ,"] [3 " 'x' ,"] ['x' " ,"] ** Syntax Error: Invalid word -- , ** Near: (line 1) , Just add some hadler to convert the invalid datatype to something else what is loadable and then parse as a block |
But such a preloader will slow down:( | |
I would like to know if string based parsing witch would handle all curent rebol datatypes can be faster or same fast as block parsing | |
Geomol 25-Sep-2006 [1421] | Gabriele, yes it works with strings. But I have words! Thing is, I parse the string input from the user and produce words in an internal format. Then I parse those words for the final output, which can be different formats. I would expect parse/case to be case-sensitive, when parsing words, but parse/case is only for strings, therefore my suggestion. |
Gabriele 25-Sep-2006 [1422] | what i'd suggest is - if case is important, don't make them into words :) |
Geomol 25-Sep-2006 [1423] | :D But it makes so much sense to work with words. |
Gabriele 26-Sep-2006 [1424] | sure, but you can only have 8k or them (unless you make sure they never end up in system/words), so if you also counted case... |
Maxim 26-Sep-2006 [1425] | another way to counter the word limit is to use #issue datatype. |
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