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World: r3wp

[!REBOL3]

Andreas
25-Mar-2010
[1827]
The third choice, making it an option at object creation time, won't 
work. We can't add refinements to MAKE.

As I mentioned before, this third choice is perfectly viable by introducing 
an additional datatype: object! vs context!, for example.
Ladislav
25-Mar-2010
[1828x6]
Yes, Andreas, my point of view is the same. This solution is clean 
and working.
(Why "cripple" all these contexts so, that Bind has to do unsolicited 
work?)
Especially when, as demonstrated, the acceptance of #1543 does not 
solve all the issues. (neither the acceptance of #1544 can)
Another variant, even simpler, may be to not use a different datatype, 
just use another syntax variant for Mold and Mold/all, if the context 
does not contain 'self - variant syntaxes for other datatypes are 
supported even now, as far as I know.
I mean syntax like: #[context ...]
(which is "free" currently)
BrianH
25-Mar-2010
[1834x5]
Not really, at least not for datatypes that depend on binding, like 
objects, functions and closures. REBOL's definitional binding model 
(I used to call it "applicative binding") makes that syntax not really 
work properly. Bindings are not restored by the MOLD/all serialized 
LOAD syntax. Regardless of whether there is a hidden 'self field 
or not, you need to create it with MAKE syntax in order to get the 
bindings restored properly.
Another datatype would work with MAKE syntax though. But it doesn't 
handle the most common case: People who need the 'self binding sometimes 
with a context, and don't need it other times with *the same context*. 
For that you need a BIND option.
One thing you shouldn't do with a programming language is assume 
that the programmer doesn't know what they want to do, so you try 
to second-guess them. That is always the worst approach because the 
programmer will always end up having to work around your guesses 
so that they can do what they actually want to do, *which only they 
can know for sure*.


It's a bad sign when the language designer talks about guessing what 
the programmer wants to do. It is much better to make a consistent, 
sensible default, then provide alternate behavior as explicitly chosen 
options. It is incredibly presumptuous for you to say that the programmer 
"didn't really want to do that", and then do something else. It is 
much better to make the behavior consistent *and documented* then 
assume the programmer *knows* what they want to do and has told you 
so.


It is not the job of a programming language or library to do what 
the programmer "wants" to do. It is the job of the programmer to 
determine what they want to do, and the job of the tool to do what 
the programmer *says* to do. And if the programmer makes a mistake, 
the tool should be as helpful as it can by throwing errors where 
it is unequivocally wrong, giving enough information to the programmer 
so they can figure out whether where they went wrong, and to behave 
consistently and predictably. Because (short of bugs) the tool is 
never at fault if it does what it's told to do. It might not be the 
right tool for the job though, but that means another tool should 
be used.
Programmers are a self-selecting lot, most of the time. It's not 
like they're end users. They should be treated as if they know what 
they're doing.
:Why 

cripple" all these contexts so, that Bind has to do unsolicited work?" 
- The behavior of BIND is documented, so it is presumptuous of you 
to say that its behavior is "unsolicited" when it is behaving as 
it is documented to behave. It is much better to use the word "unwanted" 
here. It is clear that *you* don't want BIND to do the 'self unhiding 
trick, and if there's no way to turn that off then it is a problem 
for you, as a user of the programming language. So there should be 
an option, and maybe your preferred behavior should be the default.


However, you as a language designer (this is a different you, btw) 
has to consider what other users want to do, and that won't necessarily 
be consistent with what you (as a user) would want to do. So you 
(the designer) make tradeoffs, balance concerns, look for the most 
common behavior, make sensible choices, and try not to mess up. And 
then finalize the behavior in a tool that only does what it's told 
to do, and document that tool's behavior (at least on the surface). 
Then you (as a user) can know that the tool is going to respond the 
way it is documented to do when you tell it to do something - for 
a tool, this is what it means to do what it is supposed to do :)
Steeve
25-Mar-2010
[1839]
Besides, The 'self problem has easy workarounds. just by  passing 
the wrapping context in another variable than self.
And you don't mess your code or make it slower because of that.
Lot of fuss for nothing, to my mind :)
BrianH
25-Mar-2010
[1840x2]
So does the self-not-bound problem have a workaround: BIND?. The 
question is which behavior is more common: Referring to outer contexts, 
or referring to the local context by reference? In the case of scripts, 
modules and objects it is more common to wnat to refer to the local 
script, module or object context by reference, and the outer context 
references are rare enough to make them use the workaround. In the 
case of loop or function contexts, referring to the local context 
by reference is rare, but the outer contexts are referred to all 
the time, so it makes sense to use the BIND? workaround for local 
and not override self.
And once the context is created and extends beyond the function of 
its initial creation, there is no standard for which is more common. 
Best to let the programmer decide.
Steeve
25-Mar-2010
[1842]
Perhaps more logical to do so. But as I said, I can deal with this 
problem with no overhead.

When time will come  to polish Rebol we will manage it, but now there 
are still important missing features or bugs.
Just a matter of priorities.
BrianH
25-Mar-2010
[1843x2]
This is core stuff, which will affect a *lot* of code. It's best 
to resolve this before too much of that code is written.
For instance, if BIND/self (#1544) is implemented, then I will have 
to add the /self option to every usage of BIND in DO, LOAD, IMPORT, 
DO-NEEDS, INTERN and MAKE-MODULE, and perhaps some other places in 
the mezzanine code as well. This is not a problem (really, it isn't) 
but it is better to do this now while the scope of the effects is 
still calculable.
Steeve
25-Mar-2010
[1845]
well, you'll have to touch some internal code and some mezz.
Meaning, No impact for us. 
==> Postponed with no fear :)
BrianH
25-Mar-2010
[1846x2]
No impact for end programmers because there isn't much written in 
R3 yet outside of the mezzanines. But it would impact the GUI code 
as well, so we should get this done before too much of that is written. 
And people are working on that now (mostly Henrik, but still). This 
is a really time-critical change: Whatever we choose, it should go 
into one of the next two R3 releases.
BIND is one of the most core functions in REBOL. Any change to its 
semantics would have big impact, so should be done sooner rather 
than later.
Steeve
25-Mar-2010
[1848]
Ok, I'll put 2 or 3 words in your favor to Carl :)
BrianH
25-Mar-2010
[1849]
I am starting to be in favor of BIND/self, mostly because BIND/no-self 
looks so stupid (I hate the name). YMMV :)
Steeve
25-Mar-2010
[1850]
yep but it means more work and more potential regressions
BrianH
25-Mar-2010
[1851]
Yeah, it's not R2 compatible either (which isn't necessarily a problem, 
but still).
Ladislav
25-Mar-2010
[1852]
Not really, at least not for datatypes that depend on binding, like 
objects, functions and closures. REBOL's definitional binding model 
(I used to call it 

applicative binding") makes that syntax not really work properly. 
Bindings are not restored by the MOLD/all serialized LOAD syntax. 
Regardless of whether there is a hidden 'self field or not, you need 
to create it with MAKE syntax in order to get the bindings restored 
properly." - this is a different, and quite interesting issue. As 
far as I can tell, this objection applies to any LOAD MOLD/ALL combination 
used, though.
BrianH
25-Mar-2010
[1853]
Yup. But it only really affects objects, functions and closures. 
Most types aren't affected by binding issues, and the other main 
type that is - modules - can't be serialized in a restorable form 
at all.
Ladislav
25-Mar-2010
[1854]
People who need the 'self binding sometimes with a context, and don't 
need it other times with *the same context*.

 - this is the issue in a crystal clear form. As far as I am concerned, 
 I need to bind every block supplied to the Bind function to be bound 
 the same way, when the same context is given, because I need the 
 code to behave consistently. Therefore, I dislike the state, when 
 I do not know, what "the same way" is. As opposed to that, you seem 
 to prefer to bind blocks differently, even when they are bound to 
 the same context, which seems to be necessary only in case, when 
 the usual contexts have to contain, as I call it "unsolicited" 'self.
BrianH
25-Mar-2010
[1855]
I only need to bind blocks differently to the same context *when 
I tell it to do so* (aka, when solicited). This is so I can write 
code that expects 'self to be bound without having to check whether 
the object I am binding to has the hidden 'self field. If I had to 
check for that, I would have to do that check with every usage of 
BIND where I had a 'self reference and use different code blocks 
depending on the results of that check. It is much better for BIND 
to just do what I tell it to do.
Ladislav
25-Mar-2010
[1856]
Regarding the Steeve's point: as far as I am concerned, your suggestion 
*is* consistent. (I see it as more consistent, than the current state) 
The only problem with it is, that some users may find it uncomfortable, 
since they do not need to have 'self related to e.g. Repeat, or other 
cycle functions...
BrianH
25-Mar-2010
[1857x2]
Ah, but that's a separate issue than the BIND/self vs. BIND/no-self 
thing. BIND already has the option, internally, accessible by native 
code, to not unhide and bind 'self. And the loop functions can already 
use that option, and should: They shouldn't override  'self bindings 
unless 'self has been overriden with another, unhidden 'self field.
I definitely agree with that one :)
Ladislav
25-Mar-2010
[1859]
People who need the 'self binding sometimes with a context, and don't 
need it other times with *the same context*.
 - please, exclude me from the set of People, then.
BrianH
25-Mar-2010
[1860]
Sure. That's why we have options :)
Steeve
25-Mar-2010
[1861]
too late Ladislav, your "self" is already bound
Ladislav
25-Mar-2010
[1862x2]
LOL
...nevertheless, I need not worry, since there is an option...
BrianH
25-Mar-2010
[1864x3]
And note that the 'self trick only applies to the special hidden 
'self field. And overrides of that field aren't affected: They will 
be bound or not, normally, depending on whether they are themselves 
hidden. And BIND/self shouldn't show a overriden 'self field if it 
is hidden - it should show the original 'self. Does that make sense?
And overrides -> Any overrides
Hidden fields are weird.
Steeve
25-Mar-2010
[1867]
Well Brian, Your words have no self meanings outside this discussion 
either
BrianH
25-Mar-2010
[1868]
Very existential of you: self has no meaning :)
Steeve
25-Mar-2010
[1869x2]
until it's bound to something
to a context for instance
BrianH
25-Mar-2010
[1871]
I feel like that sometimes whenever I'm single.
Steeve
25-Mar-2010
[1872]
too selfish :)
BrianH
25-Mar-2010
[1873x2]
The funny part of all this is that if the "hidden 'self field" is 
mandatory and not modifiable, R3 doesn't necessarily have to have 
a physical field to store it: It could be implicit. It's just a matter 
of whether having the physical field there is more efficient to implement 
than an implicit field (which I suspect it is).
Oh, Ladislav, you're going to hate this worse that THROW not throwing: 
What we call "contexts" in REBOL aren't contextual :)
Steeve
25-Mar-2010
[1875]
well in R2 it is explicit and modifiable
BrianH
25-Mar-2010
[1876]
well in R2 it is explicit and modifiable
 And a security hole because of this.