World: r3wp

regular expressions are *very* powerful, as long as you *don't* compare 
them with Parse :-)

I've also been confronted with UNIX users who are disappointed that 
there is no regexp implementation in REBOL. :-) they find it hard 
to believe that there might be something superior to it

It'd be fun to compare parse and REs.....

Maybe a shootout between experts in both.   Both sides could learn 
a lot.

do you think you can do everything allowed in regexp in rebol's parse?

No....I suspect they each have core abilities they excel and other 
things they can only do with ugly workarounds, if at all.
It'd be interesting to see experts bringing out the best in both.

There was some talk about that on the ML a few years back. Joel and 
Ladislav had some great exchanges IIRC. Parse and RegEx are different 
tools. I can see the power of RegExs, but they aren't for the faint 
of heart when you start doing complex things. A RegEx can be very 
concise, and can be very handy for simple pattern matching.

http://www.compkarori.com/vanilla/display/PARSE-Versus-Regexs

Thanks Ladislav!

Is it possible to use "<" ">" and so on in parse rules? (not in string 
parse).

What are you trying to parse ?

I think the answer is no, but I am not sure of the question yet. 
Please give an example input.

I'm trying to parse something as simple as 1 < 2.

hm it's possible with any-word! ...

but that does not help me very much

Yes, I'm not having much luck here.

Probably it's something like Oldes' comma problem. :/

>> lt: to lit-word! first [ < ]
== '<
>> parse [1 < 2] [number! lt number!]
== true

great, thanks!

actually not great, but working :)

Unfortunately, there's probably no similar trick that can be used 
with comma, poor Oldes

replace/all str "," comma " ; :))

you cannot use this in a dialect!

before i load the string! But not too reliable, if you have "," in 
strings.

and I'm not such a poor:-) I am using double  parenthesis in my dialect 
instead of using commas (it's ugly, but it's working)

how does some sample code look?

I still think it's a shame, that we cannot load strings with commas, 
so we cannot forexample parse javascript or actionscript

my code looks like doSomeFunction(("a" add b) 1)

i think that is hard to do perfectly. for example "\"", how to parse 
that?

in actionscript it's doSomeFunction("a" add b, 1)

doSomeFunction("a" add b # 1)
doSomeFunction("a" add b . 1)
?

I know it woud be possible to improve my dialect, but I'm not going 
to do it in near future, I'm already used to write it this way:)

I think it's quite logical to close it in parenthesis than using 
chars like #

But chars like # are easier to search/replace. But i dont defend 
my solution, yours looks ok.
Do you write your dialect-code in rebol-blocks or in a string?

And for the Rebolek: I use in RSWF this:

slash: to-lit-word first [/]
	dslash: to-lit-word "//"
	rShift: to-lit-word ">>"
	UrShift: to-lit-word ">>>"
	_bigger: to-lit-word ">"
	_less: to-lit-word "<"
	_noteql: to-lit-word "<>"
	_lesseql: to-lit-word "<="
	_biggeql: to-lit-word ">="

and then:

'* (term-op: [ins-act #{0C}])
				| slash  (term-op: [ins-act #{0D}])	;Divide
				| dslash (term-op: [ins-act #{3F}])	;Modulo
				| rShift (term-op: [ins-act #{64}])	;RShift
				| UrShift (term-op: [ins-act #{65}]);UnsignedRShift
				| lShift (term-op: [ins-act #{63}])	;lShift
				| '| (term-op: [ins-act #{61}])	;bitwise OR
				| ['|| | 'or] (term-op: [ins-act #{11}]);OR
				| ['& | 'band] (term-op: [ins-act #{60}])	;bitwise AND
				| 'and (term-op: [ins-act #{10}])	;AND

Thanks Oldes, that should help me

Volker: blocks

it's much more easier as you can use Rebol's datatypes

i thought about something like "js-load string" which would do the 
comma-conversion. But if your dialect works, no need for extra work.

maybe fixing REBOL should be better? If "." can work without problem, 
why not "," ?

interesting question why it is left out. but you would have other 
problems too, although not that often. like "\"". in rebol that is 
"\" " . in javascript "^""

Volker this is some special case, you can replace that before parsing 
string, but you cannot replace all commas in action script, some 
of them may be parts of string

Does anybody have an script to parse BNFs?

BHF's specification..

I think Bretty Handley did. Check codeconscious.

I think this should print 5 and return 'true. But it does not.

>> parse [1 2 3 4 5][any number! set val number! (print val)]
== false

Help please? :)

>> parse [1 2 3 4 5][any [set val number!] (if value? 'val [print 
val])]
5
== true

What you did was consume the five numbers, then try to set val to 
a sixth one.