World: r3wp
[!REBOL3 Proposals] For discussion of feature proposals
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BrianH 20-Jan-2011 [750] | I am trying to determine whether it would be acceptable to replace == with =? in decimal code where exact comparison is needed. Otherwise we would need to switch to prefix form if this proposal goes through, which math people don't necessarily like, or come up with operators for the equiv line. |
Andreas 20-Jan-2011 [751] | If we keep the mapping of strict-equal? to == then == would loose the added decimal precision under the new proposal. |
BrianH 20-Jan-2011 [752] | Andreas, do you like the new wording? |
Andreas 20-Jan-2011 [753] | To be honest, no. |
Ladislav 20-Jan-2011 [754] | Hmm, I would prefer the current state, then: - == is what I would use frequently, while I would not want to use =? in place of it, because of the difference - the change would require quite a lot of work, and where is a guarantee, that a new idea does not occur in a couple of weeks again? |
BrianH 20-Jan-2011 [755] | The long wording is for precision, and because these tickets serve as documentation of the issues for future reference. |
Andreas 20-Jan-2011 [756x4] | I don't want to define what the comparison dimensions are in this ticket. Leave that to an external document. |
That only hides the important issue. | |
Also, it is wrong: "equal? ... ignores case-aliasing of words". | |
equal? also ignores every other aliasing. | |
BrianH 20-Jan-2011 [760] | I changed that. |
Andreas 20-Jan-2011 [761x3] | Still wrong. |
>> a: 42 == 42 >> alias 'a "b" == b >> equal? 'a 'b == true | |
Ladislav, thanks. Seems the better option then would be to map == and !== to strict-equiv? and strict-not-equiv?. | |
BrianH 20-Jan-2011 [764] | I don't want to emphasize the aliasing thing or otherwise the ticket would need editing if/when ALIAS goes away. Still, good point. |
Andreas 20-Jan-2011 [765] | Then don't emphasize it. It is one comparison dimension that currently exists. |
BrianH 20-Jan-2011 [766] | That reminds me, need to check whether there is a ticket to remove ALIAS. |
Andreas 20-Jan-2011 [767x3] | No, there is not. |
Ignores datatypes, bindings, case, aliasing. should be sufficient | |
Also, get rid of the *NOT* mentions in the main body. If at all, mention that in a remark at the end of the ticket. | |
BrianH 20-Jan-2011 [770x2] | Good idea. |
Done. | |
Ladislav 20-Jan-2011 [772] | BTW, Same? is still less strict than my Identical? (even for decimals) |
BrianH 20-Jan-2011 [773] | Interesting. How does that happen? I thought SAME? just did a bit-for-bit comparison. |
Ladislav 20-Jan-2011 [774] | yes, but the NEW-LINE? bit is ignored |
Andreas 20-Jan-2011 [775x2] | Heh :) awesome. |
Ok, ticket's good. Thanks Brian. | |
BrianH 20-Jan-2011 [777] | That's funny :) |
Andreas 20-Jan-2011 [778] | (Maybe add a blank linke before the - EQUAL? item.)( |
BrianH 20-Jan-2011 [779] | I didn't even know there was a newline bit, though it seems obvious in retrospect. It would be lost in the transfer of the value to the stack frame for the function call I bet, because stack frames and value slots of contexts don't keep track of newlines. You'd have to pass in a reference to the block the value is stored in, I'm guessing. |
Ladislav 20-Jan-2011 [780] | wrong |
BrianH 20-Jan-2011 [781] | Even more interesting. Say more. |
Ladislav 20-Jan-2011 [782] | written in http://www.rebol.net/wiki/Identity#The_new-line_attribute |
BrianH 20-Jan-2011 [783] | I used to think that newlines in blocks were hidden values in the block itself. It makes sense to just have it be a bit in a value slot. |
Andreas 20-Jan-2011 [784x2] | It is a value bit. |
>> a: copy [1 2 3] == [1 2 3] >> new-line next a on == [ 2 3 ] >> b: copy [] == [] >> append b first a == [1] >> append b second a == [1 2 ] >> append b third a == [1 2 3 ] | |
BrianH 20-Jan-2011 [786x2] | Guess it's in all value slots, not just the ones in block types, and just ignored when inapplicable. |
At least that makes the value slot easier to implement. Good choice. | |
Ladislav 20-Jan-2011 [788] | Well, it is not ideal this way, for two reasons: - it does not affect all possible line break positions in a block (there are n + 1 such positions in a block of length n, as can be easily figured) - it "pollutes" the values, affecting their identity, e.g. |
Andreas 20-Jan-2011 [789] | Well, the latter is probably why same? does not respect this bit, no :) ? |
BrianH 20-Jan-2011 [790] | It also makes the "immediate values aren't modifiable" argument a little more iffy. |
Ladislav 20-Jan-2011 [791x3] | But the differences are real, that is like putting our head into the sand pretending there is no danger nearby |
{It also makes the "immediate values aren't modifiable" argument a little more iffy.} - I do not use the notion of "immediate values", neverheless, it does not, I would say | |
(the NEW-LINE attribute is immutable) | |
BrianH 20-Jan-2011 [794] | It's mutable with the NEW-LINE function :) |
Ladislav 20-Jan-2011 [795x3] | No, see my article |
It is exactly as mutable as the sign of an integer is, when using the Negate function | |
(not at all) | |
BrianH 20-Jan-2011 [798x2] | Immediate values are a bit iffy concept in REBOL anyways, so it's probably for the best that you don't use the notion. Nonetheless, there is a documentary typeset in R3 called immediate!, which includes the values that are fully stored within a value slot, rather than referencing memory elsewhere. |
That is what I meant by "immediate values". | |
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