World: r3wp
[!REBOL3]
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Pekr 19-Apr-2010 [2063] | also - is following operation what is expected? >> lx: lx or #{8000} == #{80000000000003FE} >> to-integer lx == -9223372036854774786 Whereas I would expect OR being performed on the lowest bytes! >> #{8000} or #{03FE} == #{83FE} >> #{8000} or #{03FE} == #{83FE} |
Maxim 19-Apr-2010 [2064] | just like strings return chars. |
Pekr 19-Apr-2010 [2065x2] | I find binary handling, along with inability to join binary resuls severyl broken |
Max - this is imo wrong ... how is that usefull? I did not ask it return integer ... imo /index should still return original type | |
Maxim 19-Apr-2010 [2067x3] | binary is a string of bytes, so that it returns 8 bit integers to me is VERY usefull. |
what you say is equal to: a: [1 2 3 4 5 6] a/3 == [3] | |
binary is a series, and indexes return, like all other series, the element which constitutes it at the index you give it. | |
Pekr 19-Apr-2010 [2070] | OK, I can accept that ... but is R3 OR operation, performing OR on the higher bytes correct? |
BrianH 19-Apr-2010 [2071] | If you are concerned about alignment, manage it yourself. The behavior is extremely consistent, so that such management is easy. |
Pekr 19-Apr-2010 [2072x2] | Brian: how is that supposed to be easy? The way it is, I have to count on the internal representation binary size - here 64 bits ... |
I am asking binary 1024 to be ORred with binary #{8000}, the result is imo crap :-) | |
BrianH 19-Apr-2010 [2074] | Yes, but that 64 bits is a known, consistent quantity. Very predicatble. |
Pekr 19-Apr-2010 [2075x2] | but the result is imo wrong anyway, no? |
This is correct: >> (to-binary 1022) or (to-binary 32768) == #{00000000000083FE} | |
BrianH 19-Apr-2010 [2077x2] | No, binaries are right-padded. You should have been ORing with a binary of the proper sixe. R3 was nice enough to add the 0s that you didn't provide. It's just your assmption that was off :( |
sixe -> size | |
Pekr 19-Apr-2010 [2079x5] | no, it is not ... |
>> to-integer #{8000} == 32768 | |
What assumption are you talking about? If you were right, then above binary should be paddedd too ... | |
I was orring original converted 1022 with 32768 and got a crap ... | |
If I should care about internal representation of binary, then it is not usable datatype for me. How are my operations supposed to be fast? | |
BrianH 19-Apr-2010 [2084] | TO-INTEGER and TO-BINARY integer left-pad. OR and AND don't pad at all (in theory), they just make up for your error in not providing the whole binary. It is like blocks and none. |
Pekr 19-Apr-2010 [2085] | can't you see that? Following iperations are imo compatible, and should provide me with identical results ... >> (to-binary 1022) or (to-binary 3278) == #{0000000000000FFE} >> (to-binary 1022) or #{8000} == #{80000000000003FE} >> to-integer #{8000} == 32768 |
BrianH 19-Apr-2010 [2086] | You were assuming padding, when there is no way to pad those operations without breaking someone's assumptions. If you are doing binary conversions and working with binary values you are assumed to know what you're doing. |
Pekr 19-Apr-2010 [2087x2] | simply put, in second case, 1022 is not orred with 32768 |
No, OR/AND should be applied from the right side, not from the left side .... | |
Maxim 19-Apr-2010 [2089] | pekr, there are things in Computer science which just are. Just like there are things in maths, which just have to be accepted. R3 isn't inventing much of anything here, its actually much closer to normal boolean algebra than R2 ever was... FINALLY. in binary algebra, normally, things are right padded when sizes don't match... that's just how the maths behind it where defined long ago. binary manipulation is an advanced topic, and you can't assume anything. |
BrianH 19-Apr-2010 [2090] | Simply put, you are assuming that TO-BINARY and TO-INTEGER are reversable when you don't provide the whole binary equivalent of the integer. There is no reason that this would be true. |
Pekr 19-Apr-2010 [2091x2] | non reversable operations are evil ... can't remember the case, but we already had such discussion in regards to some R2 area .... |
Once again - you are imo wrong. R3 should not allow to enter any other than full binary padded format then! | |
BrianH 19-Apr-2010 [2093] | There's no reason that the operation *would* be reversible. The TO-INTEGER was correcting for an incomplete binary in a DWIM way. If you had provided the whole binary it wouldn't have had to do that. And the TO-BINARY had a whole integer, so it didn't have to correct. |
Pekr 19-Apr-2010 [2094x2] | How is that in Python, they can safely do it? elif l < 0x4000: l |= 0x8000 self.writeStr(chr((l >> 8) & 0xFF)) self.writeStr(chr(l & 0xFF)) The second line is - l: l or #{8000} |
What if I will have 32 or 128 variant of REBOL? Will I have to adjust my expressions, hence change my code? There is no reason to not perform OR/AND on the lowest byte, not the highest byte imo ... | |
Maxim 19-Apr-2010 [2096] | pekr, to-integer is a helper func. its like form, not mold. you shouldn't be using to-integer.. for binary arithmetic. rebol is reversible: >> b: to integer! a == 32000 >> b: to binary! a == #{0000000000007D00} >> a: to integer! b == 32000 |
Pekr 19-Apr-2010 [2097] | I mean 32bit or 128bit |
BrianH 19-Apr-2010 [2098] | It is not that Python was doing it "safely", it was that Python was doing it differently when there is no standard for what to do here. |
Pekr 19-Apr-2010 [2099] | OK, one other areas, where R3 makes things difficult ... |
BrianH 19-Apr-2010 [2100x2] | Pekr, binary operations are assuming that the binary is part of a stream. The "lowest" byte could be megabytes away. |
And I was wrong, the Python in your example was not operating on binaries at all, it was operating on integers that were specified in hex syntax, which is a completely different thing that REBOL has no support for at all. Not the same thing. | |
Pekr 19-Apr-2010 [2102] | binary streams and binary arithmetics are different issue to me ... |
BrianH 19-Apr-2010 [2103] | 0x8000 and #{8000} are completely different concepts. |
Maxim 19-Apr-2010 [2104] | pekr... here I must say, you really do not know what you are talking about. all the binary changes brought to R3 are due to user responses about how fucked up it really was to use binary stuff in R2. really. I had to build binary data-driven TCP servers in R2, for example, and I had to use so many shitty work-arounds and fix up numbers .. it was an ordeal. R3 makes binaries, clean, no hassle and simple. they are a simple series of bytes, nothing more. they are manipulated from the start to the end in that order. that's all there is to it. |
BrianH 19-Apr-2010 [2105] | 0x8000 is an integer specified in a different syntax, one which REBOL has no equivalent to but C does. |
Maxim 19-Apr-2010 [2106] | and 0x8000 will be a different value based on what variable type it is assigned to. 0x8000 can be: #{8000}, #{00008000}, or #{0000000000008000} you can't tell . |
Pekr 19-Apr-2010 [2107x2] | So once again - I can work with two binaries being converted at the SAME time: >> (to-binary 1022) or (to-binary 3278) == #{0000000000000FFE} But I can't work on two binaries stored at different time: >> l: to-binary 1022 == #{00000000000003FE} >> l or #{8000} == #{80000000000003FE} |
Max - please stop this fanboyism. I know why R3 was brought to us, and I know how fucked up R2 binary was. I am glad we are converting to binary as one value, not as separate values, like in R2, that was not usefull. But my above case will make headache to many ppl, I can bet ... | |
Maxim 19-Apr-2010 [2109] | pekr... have you been reading... #{8000} is NOT A NUMBER its a SERIES OF BYTES. you keep refereing to binaries as if they where numbers. THEY ARE NOT |
Pekr 19-Apr-2010 [2110x2] | and 0x8000 will be a different value based on what variable type it is assigned to. ... do you REALLY mean it? 0x8000 is just one value, period ... |
... and you are talking about CERTAIN binary value as of stream of unknown position, hence not having value at all :-) | |
Maxim 19-Apr-2010 [2112] | to-binary 1022 creates a string 16 bytes (64 bits). |
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