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World: r3wp

[!REBOL3]

BrianH
3-Mar-2010
[1166x2]
We want that behavior and much code depends on it. You can add the 
none explicitly if you need that value.
And CONSTRUCT doesn't evaluate anything, so safety is not an issue.
Paul
3-Mar-2010
[1168x2]
Still we need to check it and we could simply have another switch 
that could fix construct to be even more superior.
construct/as-is
BrianH
3-Mar-2010
[1170]
We have that option, except it's called /only.
Paul
3-Mar-2010
[1171x2]
that doesn't work for this issue
>> a: construct/only [c: d: 1]
== make object! [
    c: 1
    d: 1
]
BrianH
3-Mar-2010
[1173]
Chained assignments aren't an issue, they are an intended feature.
Paul
3-Mar-2010
[1174]
I understand that but we need a feature in which they are NOT.
BrianH
3-Mar-2010
[1175]
>> construct/only [a: b:]
== make object! [
    a: none
    b: none
]
Paul
3-Mar-2010
[1176]
that is still a chained assignment
BrianH
3-Mar-2010
[1177]
But that's not a problem.
Paul
3-Mar-2010
[1178x4]
Ok, it doesn't seem your following me, so let's forget about construct.
We need a function that does not evaluate or do chain assignment.
But let's you access the elements as if they are an object and can 
already exist in a block style spec that can be passed to context.
So it would be similiar to construct except without the chain assignment.
BrianH
3-Mar-2010
[1182]
CONTEXT does chained assignment too, btw.
Paul
3-Mar-2010
[1183]
Yes, so does almost everything in REBOL since day 1.  Surely your 
not thinking I just stumbled upon that discovery.
BrianH
3-Mar-2010
[1184]
Do you need to access the elements as if they are in an object, or 
elements that are actually in an object?
Paul
3-Mar-2010
[1185]
I'm just seeing room for improvement here to make REBOL even more 
safe.
BrianH
3-Mar-2010
[1186]
But there are no safety issues with chained assignment.
Paul
3-Mar-2010
[1187x5]
I could simply just use a block if I want to access elements but 
that isn't ideal for conversion to an object when I decide I want 
that flexibility.
Not so my friend.
That is where your wrong.
Ideally you would use a construct for assignments of values passed 
via cgi.
While those items are string values it could still potentially be 
exploited in my opinion.
BrianH
3-Mar-2010
[1192]
It sounds like you need a PARSE wrapper.
Paul
3-Mar-2010
[1193x2]
Or we just make sure that such assignment is not chained -       
       ;-)
bbl
BrianH
3-Mar-2010
[1195x4]
If the CGI data is parsed properly it should never generate anything 
other than pairs. If it ever generates chained assignments that is 
an error in your parse rules, not CONSTRUCT.
By "pairs" I mean name-value pairs, not pair! values.
On the other hand, you can APPEND to objects and maps in R3, so you 
don't need the block at all.
And appending to objects doesn't chain assignments.
Paul
3-Mar-2010
[1199x3]
I'll create my own function.
problem solved.
is this really a valid email?

 >> email? load "carl@.com"
== true
BrianH
3-Mar-2010
[1202]
It doesn't check whether the email address is valid, just that the 
syntax is valid.
Paul
3-Mar-2010
[1203]
I could suppose that syntax is valid if I worked my ISP was a root 
server.
Gregg
4-Mar-2010
[1204]
Paul, creating your own func is the way to go for that. And emails 
can be very complex. REBOL doesn't try to validate against the true 
grammar, it just looks for @.
Steeve
4-Mar-2010
[1205]
actually the smallest valid email in Rebol is 1 char + @
>> type? 1@
== email!
Gregg
4-Mar-2010
[1206]
:-)
Sunanda
4-Mar-2010
[1207]
cc#1509 -- Thanks Brian for consolidating a whole handful of bug 
reports [and/or misunderstandings].
That should help focus the core RT crew into clarifying / fixing.
Cyphre
4-Mar-2010
[1208]
Paul, I usually test email entry using simmilar code to this:
if any [
    not email? try [email: first load/next cgi/email]
    all [
		not read join dns:// email/host
		not read rejoin [dns:// "smtp." email/host]
		not read rejoin [dns:// "pop." email/host]
		not read rejoin [dns:// "mail." email/host]
		not read rejoin [dns:// "www." email/host]
		...
	] 
][
	print "email is not valid or your email server is unavailable"
]


Worked well in most cases for me but I bet others might have more 
sophisticated solutions.
BrianH
4-Mar-2010
[1209]
Thanks, Sunanda, never would have figured it out without your help.
Gabriele
4-Mar-2010
[1210]
Sunanda, you're still seeing this the wrong way. ATTEMPT never returns 
an error. the "error" you are talking about happens outside of ATTEMPT, 
so it can't guard against it.
Andreas
4-Mar-2010
[1211x5]
Yes, Gabriele, that's how things are currently implemented.
The question is, should the error occur inside the attempt instead?
I think that RETURN, EXIT and BREAK, CONTINUE should be only available 
in their respective contexts (functions, and loops). CATCH/THROW 
will need special treatment. QUIT, Q, HALT can be left as is.
I am well aware that this would be a significant change in semantics.
Brian claims that "most of the code we call in REBOL is non-local, 
meaning not directly nested in blocks". I on the other hand think 
that for the specific functions under consideration (RETURN, EXIT, 
BREAK, CONTINUE) this is mostly not the case.