World: r3wp
[Core] Discuss core issues
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Maxim 19-Sep-2010 [18233] | statement: skip post -2 change find statement 'fixed 'changed ? |
Ladislav 19-Sep-2010 [18234x5] | >> forall (in a 'b) [print a/b/1] 1 2 3 4 5 Looks more than sufficient for me. |
The above is R3, though | |
The evaluation of these "partially evaluated arguments" has changed this way | |
Nevertheless, I do not like the header of the FORALL function, since the WORD argument is actually used to supply two values to the function, which is not a KISS strategy | |
(if this "two in one" method were that good, why it is not used by FOREACH, etc.?) | |
Maxim 19-Sep-2010 [18239] | cause that's how they differ? |
Ladislav 19-Sep-2010 [18240x2] | Cetera censeo, the "two in one" argument passing method is improper, and should not be used |
#1653 | |
Maxim 19-Sep-2010 [18242x3] | would we be just using forall word word [print word/1] all the time ? |
woudn't | |
<arghh> wouldn't | |
Ladislav 19-Sep-2010 [18245x3] | all the time ? |
isn't it more frequent, that you actually do: my-word: [1 2 3] forall my-word [do something...] ? That should properly look this way: forall my-word [1 2 3] [do something...] | |
Not using FORALL, I actually do not mind, I just wanted to point out what is wrong about it | |
Henrik 19-Sep-2010 [18248] | this is one of the reasons I don't use FORALL very often, but resort to repeat i length? <something> |
Maxim 19-Sep-2010 [18249] | when I have used forall (and its really rare, cause until is much better, usually) I never use litteral data directly, its always some data which is already setup elsewhere. |
Ladislav 19-Sep-2010 [18250x5] | I am pretty sure, that *if* FORALL was defined properly from the start, everybody would perceive a change to the "two in one argument passing method" inappropriate. But, since it is a backward compatibility issue, you do not see what is wrong about it. Nevertheless: the WORD argument is an independent word, which is used to "define" a local in the BODY argument, that is why it actually does not make sense to use it as a "series container" on entry |
(where it is "nonlocal") | |
To make it absurd, even REPEAT could be modified to use the "two in one argument passing method". Would you find it proper? | |
...and if not, why? | |
...and I don't think, that an argument "because that is how REPEAT differs from FORALL" makes any sense as an argument | |
Maxim 19-Sep-2010 [18255x2] | well repeat already uses 2 arguments. |
ah sorry... read your statement the wrong way. | |
Ladislav 19-Sep-2010 [18257x3] | In my opinion, different functions are defined not because we like to have different functions, but because they do different things for us |
Assuming (hypothetically), that FORALL did not use the "two in one" method, the Graham's example would look as follows: forall b a/b [print a/b/1] , which is preferable, since it clearly suggests, that the word 'b in the BODY is actually not the same word as in a 'b | |
Aha, it seems, that I noticed one more strangeness in this. Why actually the expression: forall (in a 'b) [print a/b/1] prints what it does in R3? | |
Graham 19-Sep-2010 [18260] | the reason I use 'forall is so I can remove elements of a series as I traverse it. so forall series [ if series/1 = something [ remove series ]] which 'foreach doesn't allow because you don't have a reference to where you are in the series |
Maxim 19-Sep-2010 [18261x3] | use remove-each its MUCH faster. |
using your example it becoms. remove-each [if series/1 = something] | |
actually... its: remove-each [series/1 = something] | |
Henrik 19-Sep-2010 [18264] | remove-each is indeed much faster and it's a native. |
Maxim 19-Sep-2010 [18265] | argh... I'm reallly tire. |
Graham 19-Sep-2010 [18266] | Only because Carl made it native! |
Maxim 19-Sep-2010 [18267x2] | remove-each item series [item = something] |
not just because its native... its in the way it actually manages the removal... it only re-creates the series once, when its done. using other methods, you are tampering with the series at each change, and it has to copy the series over and over. | |
Graham 19-Sep-2010 [18269x2] | remove-each mistake maxs-mistakes [ true ] ? |
Is that the syntax? :) | |
Maxim 19-Sep-2010 [18271] | yep |
Steeve 19-Sep-2010 [18272] | Maxim about remove-each, what do you mean by: - "it only re-creates the series once, when its done". |
Maxim 19-Sep-2010 [18273] | what I have been explained is that it makes a new series and only copies when remove is false. then replaces the pointer within the series to the new one. |
Ladislav 19-Sep-2010 [18274x2] | Steeve, removal of one object from a block is an O(n) operation, where n is the length of the series. That would make a naive implementation O(n ** 2), while REMOVE-EACH is just O(n) |
...but, actually, no re-creation of series happens anyway | |
Maxim 19-Sep-2010 [18276x3] | ah yes.. true.. it just copies over itself. |
Ladislav, one question I've always wondered and I'm sure you know. | |
does CLEAR only set the soft size of a series or does it actually truncate the internal buffer of a series? | |
Ladislav 19-Sep-2010 [18279x3] | the former |
CLEAR is just O(1) | |
although,maybe, that in some cases, the GC is able to reassign a smaller part of memory to the series, but I doubt it | |
Steeve 19-Sep-2010 [18282] | Are you sure about that ? I don't tink remove-each create any temporary buffer. when I compare the footprint of foreach and remove-each, they are the same (which means nothing, because i don't see why foreach need to create so much temporary blocks) |
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