Bug! Rebol's parsing of urls is incorrect.

== url!

== url!

== url!

== url! My email client correctly leaves out the exclamation mark "!", period ".", question mark "?" and comma "," but Rebol treats all of them as part of the URL, which is clearly incorrect. Andrew Martin ICQ: 26227169 http://members.nbci.com/AndrewMartin/

There is a difference between a legal, parsed URL and REBOL's detection of datatypes. REBOL parses pretty much anything that starts with text: followed by something else as a url! datatype. That does not mean that all of them are necessarily legal URLs. In fact, whether a URL is legal or not depends completely on the scheme. For instance the first component after (scheme):// does not necessarily have to be a host name. Just take file://a,b,c! as an example. This is completely legal, yet your email client might incorrectly stop after the "a". REBOL's scanner has no knowledge of schemes and their particular rules for URL wellformedness, because otherwise it would be impossible to add user-defined schemes with their own URL schemes. It would also prevent you from doing some types of dynamic URL generation/manipulation at the series level. The actual URL parsing and check for wellformedness is done much later, when you try to open a port with a URL. Individual schemes have their own parsers. There is one universal parser (decode-url), which is what most schemes use to parse URLs. It knows about the most common URL formats, including username/password, hostname, ports directory and file parts. The same concept applies to scanning vs. parsing of emails. -- Holger Kruse [holger--rebol--com]

-- Ryan Cole Programmer Analyst www.iesco-dms.com 707-468-5400 I am enough of an artist to draw freely upon my imagination. Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world. -Einstein

== http://www.rebol.com!

== url!

== http://www.rebol.com! 'load was where I first noticed the problem. Andrew Martin ICQ: 26227169 http://members.nbci.com/AndrewMartin/

around

I suspect that even if you had such a validating parser rule in the scheme it would not make any difference to the way Rebol scans the url! datatype - for the reason that Holger pointed out. Thus it would not help using the load/next function either. You may be better off writing your own parser. By doing so you are adding crucial knowledge to the solution that Rebol doesn't have - that being that your input is actually plain text - not a Rebol loadable dialect. Also, I recall a warning that Larry gave some time back about using load - it puts the words in system/words thus using up a finite resource. So if I were to load this email I'm writing (apart from the errors) I would have words like "also", "recall", "warning" and "larry" in system/words. I do use load for loading tag names and attributes in my html manipulation scripts, but I calm myself with the knowledge that the number of tag names is probably finite. Plain text though is coming from a much larger domain of possibilities. That said, having a validating parser rule as part of each scheme does seem appropriate. It would allow you to make your own parser and know that it will not need modification as more schemes are added. Brett.

it would not make any difference to the way Rebol scans the url! datatype - for the reason that Holger pointed out. Thus it would not help using the load/next function either. That's right. I found out the problem in the first place by using 'load/next. It would be nice though if the scanner checked the scheme name and "dived into" a parser rule in the appropriate scheme.

crucial knowledge to the solution that Rebol doesn't have - that being that your input is actually plain text - not a Rebol loadable dialect. It's the best kind of dialect, plain text with rebol values interspersed. :-)

it puts the words in system/words thus using up a finite resource. So if I were to load this email I'm writing (apart from the errors) I would have words like "also", "recall", "warning" and "larry" in system/words. I do use load for loading tag names and attributes in my html manipulation scripts, but I calm myself with the knowledge that the number of tag names is probably finite. Plain text though is coming from a much larger domain of possibilities. I'll have to check for that. Good point.

seem appropriate. It would allow you to make your own parser and know that it will not need modification as more schemes are added. It'll also mean less duplication of effort on the part of everyone. Thanks Brett. Andrew Martin ICQ: 26227169 http://members.nbci.com/AndrewMartin/

when you try to open a port with a URL. Then it looks like I'll have to build a parser than can check for webformedness and use that to extract absolute URLs and emails from plain text. I was hoping that 'load/next would do the trick for me. Thanks Holger. Andrew Martin ICQ: 26227169 http://members.nbci.com/AndrewMartin/

flexibility on its use? A seperate pickier and slower data validation function could be used to say that something is not ready for the outside world. After all, 'type?'s docs just say "Returns a value's datatype," no mention of validity. What we really need is a validating parser/loader/scanner, one for each scheme. I've been skimming through the schemes and noticed there's some repetition in Rebol's open functions, which could be abstracted out. Also, if a validating parser rule was incorporated into each scheme to check for wellformedness, that would be good. As it stands now, I can't use Rebol's 'load/next function to extract a URL from plain text with punctuation around it. For example extracting the URL from the following: "Rebol's HQ" http://www.rebol.com! requires me to write my own URL parser. Andrew Martin ICQ: 26227169 http://members.nbci.com/AndrewMartin/

around

Sorry if off-topic, but I came too late to the discussion. I remember the case when I wanted to check for the value and if it is an email. Example: ->> eml: to-email "just.a.string" == jut.a.string ->> type? eml == email! ->> email? eml == true ->> Then Elan (IIRC) explained me that even if I have some value marked as certain datatype, it doesn't mean it has to be actullly valid email adress for e.g. But even RT is/was using email? some-value to show outside world how it is easy to check for email values. But as you can see, it has not to be always true.Maybe the 'load is the way? ->> email? load "just.a.string" == false ->> email? load "[just--a--string]" == true ->> -pekr-

Actually those open functions you are seeing are not defined separately for each scheme. They are defined for the root protocol, and most schemes inherit them at object (scheme) creation time. -- Holger Kruse [holger--rebol--com]

Correct me if I am wrong, but REBOL copies functions when cloning an object (to bind them to the new context). So each handler has a copy of the same function. I think Andrew is suggesting to use delegation instead. Regards, Gabriele. -- Gabriele Santilli <[giesse--writeme--com]> - Amigan - REBOL programmer Amiga Group Italia sez. L'Aquila -- http://www.amyresource.it/AGI/

for each scheme. They are defined for the root protocol, and most schemes inherit them at object (scheme) creation time. Gabriele wrote:

object (to bind them to the new context). So each handler has a copy of the same function. That's right. It's particularly obvious as a result of: mold system

Actually, I wasn't, but delegation sounds like a good idea. The area of copying functions in a object is a "painful" area in Rebol. I'd really like to put a path in an object like: o: make object! [f: func [] []] oo: make o [] and see that the result of: probe oo would be something like: make object! [f: o/f] Andrew Martin ICQ: 26227169 http://members.nbci.com/AndrewMartin/