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World: r3wp

[Core] Discuss core issues

Andreas
14-Jul-2010
[17441]
Brian: would you mind describing a single _semantic_ aspect of the 
the DED's model?
BrianH
14-Jul-2010
[17442]
1 represents an "integer".
Andreas
14-Jul-2010
[17443]
What is semantic about that?
Ladislav
14-Jul-2010
[17444]
So what we need is a function that does a better job of serializing 
the in-memory data model, and probably a new syntax to represent 
it.

 - actually not, as I have no problem to demonstrate, since the goal 
 of script preprocessing (which is the subject of this discussion) 
 can be reasonably achieved using the LOAD and SAVE/ALL pair.
Andreas
14-Jul-2010
[17445]
1 is syntax for the "integer!" type, no semantics involved. The whole 
point of _data_ is that it has no semantics but a syntactic structure. 
That may not be REBOL's standard terms, but computer science instead.
BrianH
14-Jul-2010
[17446x2]
Ladislav, script preprocessing doesn't require the whole range of 
in-memory data structures, just a subset. What I am talking about 
is outside of that subset.
Andreas, the integer! type is a semantic concept. As is nested blocks.
Andreas
14-Jul-2010
[17448]
a syntactic category is per definition no semantic concept. but that's 
really getting off-topic here.
Steeve
14-Jul-2010
[17449]
semantic battle
Andreas
14-Jul-2010
[17450]
We are only concernce with this subset of data structures and we 
see that LOAD + SAVE in sequence does not adequately preserve even 
those.
Ladislav
14-Jul-2010
[17451]
Steeve, that is exactly a false impression, the original topic is 
about REBOL syntax preservation, all semantic detours are off-topic
Andreas
14-Jul-2010
[17452]
And the argument is that a pair of functions with the names of LOAD 
and SAVE which pretty much cry *duality* is to be considered harmful 
if they willingly violate their implied duality.
Steeve
14-Jul-2010
[17453]
but you both use a different semantic to argue around your subject
BrianH
14-Jul-2010
[17454x2]
Taking the decimal! type as an example, the DED syntax (what LOAD 
can handle) can accept a wider range of decimals than can be represented 
in-memory. Those that can't be represented directly in memory are 
approximated. Since those approxiimations tend to happen in the 16th 
to 17th digits, they can be "undone" by ignoring those digits in 
the "friendly" output.
If you want to consider LOAD and SAVE not being a duality to be harmful, 
go ahead, considerations like that are a matter of opinion.
Andreas
14-Jul-2010
[17456]
This "unapproximation" is simply broken then.
BrianH
14-Jul-2010
[17457x2]
Yes, Andreas, that is what I have been saying.
But they are still useful, even if they are limited.
Andreas
14-Jul-2010
[17459]
They are not limited, they are broken.
Ladislav
14-Jul-2010
[17460]
Right, since it "unapproximates" all values, i.e. values, that aren't 
"approximated". Therefore, it either can be called a "broken unapproximation", 
or, more precisely, no unapproximation at all,since it actually is 
not "unapproximation"
BrianH
14-Jul-2010
[17461]
Reapproximation for MOLD, no approximation for MOLD/all, approximation 
depends on the digits for LOAD, at least for decimals.
Ladislav
14-Jul-2010
[17462]
Well, is that worh any discussion? The transformation clearly transforms 
values so, that after being transformed, additional error is introduced.
BrianH
14-Jul-2010
[17463x2]
Maxim, we can't extend the existing serialized form to represent 
everything in memory, because binding, cycles and DAGs aren't representable 
without some kind of reference index. So even rebin wouldn't do, 
we'd need something like RIF.
Ladislav, it was just an example to illustrate that the abstract 
REBOL that is accepted by LOAD doesn't exactly represent the real 
REBOL in memory. But it does represent enough to do source processing 
by a preprocessor.
Andreas
14-Jul-2010
[17465x3]
If you want to consider LOAD and SAVE not being a duality to be harmful, 
go ahead, considerations like that are a matter of opinion.
Ha, at least we got to the point. This opinion was all this discussion 
was originally about.
As a matter of fact, LOAD and SAVE/all form a far better duality 
as far as REBOL source is concerned. So Ladislav and I argued that 
making /all the default for SAVE would be a sensible thing to do.
BrianH
14-Jul-2010
[17468]
The problem with that is that opinions vary. This has been happening 
a lot lately. Just the other day, Sunanda claimed in CureCode that 
assignments were unsafe. I couldn't even answer a statement like 
that without it turning into a flame war.
Andreas
14-Jul-2010
[17469x2]
Sure, that's why we are discussing it at all. Besides getting mightily 
side-tracked in semantic debates that do mostly not pertain to this 
issue, to only argument against this suggestion I heard was that 
SAVE should behave symmetrically to MOLD, not dually to LOAD.
A nice result of this side-tracking is that I now consider mold completely 
broken for decimals, as it applies a hack that maybe once was appropriate 
for single precision floats, but certainly no longer is for double 
precision floats.
BrianH
14-Jul-2010
[17471]
SAVE and MOLD are explicitly designed to be newbie-friendly - that 
includes being able to have MOLD generate the value 0.1, which is 
not representable by the (misnamed) decimal! type in memory. And 
#[] syntax has been judged to not be newbie-friendly, or at least 
an ugly thing that only power users do. If you want to reverse that 
decision, fine, but it's unlikely.
Andreas
14-Jul-2010
[17472]
Once again, 0.1 is not the point here. That's the result of a flawed 
pretty-printer.
BrianH
14-Jul-2010
[17473]
>> mold/all 0.1
== "0.10000000000000001"

Many values that developers usually write out in decimal aren't representable 
in memory. Welcome to the wonders of IEEE754.
Andreas
14-Jul-2010
[17474x2]
Funny, what platform?
>> mold/all 0.1
== "0.1"
BrianH
14-Jul-2010
[17476]
Andreas, you are not getting that the whole point of MOLD and SAVE 
is to be a pretty-printer.
Ladislav
14-Jul-2010
[17477]
Windows
Andreas
14-Jul-2010
[17478]
What is FORM supposed to be then?
BrianH
14-Jul-2010
[17479]
A pretty-printer for users rather than developers.
Steeve
14-Jul-2010
[17480]
;-) Someone should start to write our chronicles. When I will be 
an old hag, I would be fun to read our old debates.
BrianH
14-Jul-2010
[17481]
Andreas, please use R3 when talking about MOLD/all for decimals - 
it's broken on R2.
Andreas
14-Jul-2010
[17482x2]
Fair enough. So your take is that LOAD/SAVE forms no duality because 
of MOLD is supposed to do "developer pretty printing" but for absolute 
newbie developers, not for developers familiar with e.g. #[] syntax.
>> mold/all 0.1
== "0.1"
Ladislav
14-Jul-2010
[17484]
the whole point of MOLD and SAVE is to be a pretty-printer

 - looks true for MOLD, but SAVE does not print, so this does not 
 apply in any reasonable sense
Andreas
14-Jul-2010
[17485]
Well, that's the SAVE should be symmetric to MOLD argument. It's 
a fair point; just one I personally disagree with.
BrianH
14-Jul-2010
[17486x2]
MOLD doesn't priint either. Very few pretty-printers print. It's 
a jargon term.
For that matter, PRINT doesn't really print either :)
Steeve
14-Jul-2010
[17488]
btw, we are not really here
Ladislav
14-Jul-2010
[17489]
As I said, I can actually live with it, but, what I am unable to 
live with is, that this gotcha is nowhere documented, and it is a 
gotcha par excellence, as demonstrated
BrianH
14-Jul-2010
[17490]
Andreas, which platform are you using? That is a serious platform-specific 
bug you are demonstrating there, and should be reported.