World: r3wp
[Core] Discuss core issues
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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. |
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