World: r3wp
[Core] Discuss core issues
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[unknown: 5] 31-Mar-2009 [13345x2] | The also function should be used as the last line of your function. |
I gotta run for a bit but will be back in about an hour or sooner. | |
Geomol 31-Mar-2009 [13347x3] | Yes, I understand that. What I don't understand, is how you call these functions, and what does on with the data, you get returned from your function. Do you have code examples online, I can look at? |
what *goes* on ... | |
Using ALSO returns some data. If your code look like this: mp3-data: load-mp3-function and that load-mp3-function ends with an ALSO, setting the local var to none, you still have a full copy in mp3-data. Actually you end up having 2 copies for some time, until the garbage collector frees the local version. Later in your code, you need to set mp3-data to none to free to memory (which the garbage collector does). Now, is this how you use ALSO and why you need it? | |
Izkata 31-Mar-2009 [13350x5] | Most of mine are for conciseness - for example, when no data needs to be returned: Client: first wait Listen Data: also (copy Client) (close Client) |
but, like before, say that happened in a function | |
Process: func [Client][ ..do stuff.. return also (copy Client) (close Client) ] Client: first wait Listen Logfile/add Process Client | |
I'll look for some actual code I'm using soon | |
Pread: func [URL /local Port][ Port: open/binary URL Port/timeout: 3 * 60 return also (copy Port) (close Port) ] | |
Geomol 31-Mar-2009 [13355x2] | What happens, if the connection fails? |
Does my version work the same as yours beside the timeout? newPread: func [URL] [read/binary URL] And can the timeout be set somewhere in the system object? | |
[unknown: 5] 31-Mar-2009 [13357] | f: has [file][file: read %somefile also copy/part file 30 file: none] |
Geomol 31-Mar-2009 [13358x2] | My guess is, that your version using ALSO use the double memory, that mine does (because of the copy). |
Paul: f: does [copy/part read %somefile 30] | |
[unknown: 5] 31-Mar-2009 [13360] | John, yes true but what if you want to do several things with the local in the function? Are you going to copy it every time? |
Geomol 31-Mar-2009 [13361] | Then do: f: has [file] [file: copy/part read %somefile 30 comment "do something with the file" return file] |
[unknown: 5] 31-Mar-2009 [13362x2] | Yeah my example used copy so that might defeat it. |
f: has [q][q: [] append q read %blah remove/part q 20 also q q: none] | |
Geomol 31-Mar-2009 [13364x3] | That doesn't work. your local q holds data after returning from F. (maybe an error) |
>> f: has [q] [q: [] append q "kdfjkd" also q q: none] >> a: f == ["kdfjkd"] >> a == ["kdfjkd"] >> source f f: func [/local q][q: ["kdfjkd"] append q "kdfjkd" also q q: none] | |
It seems, q has data in the end. | |
[unknown: 5] 31-Mar-2009 [13367] | I didn't try it :-) |
Geomol 31-Mar-2009 [13368] | My opinion right now is, that ALSO sucks big time! :-) Maybe someone can convince me otherwise. |
[unknown: 5] 31-Mar-2009 [13369] | I couldn't but I see the difference using it. |
Geomol 31-Mar-2009 [13370x2] | It seems hard to use, it often result in using twice the memory, that people expect. And it might even lead to pad program structure. |
pad -> bad | |
Izkata 31-Mar-2009 [13372] | newPread: func [URL] [read/binary URL] ; I only want the large timeout in this function, not in other 'read calls f: has [file] [file: copy/part read %somefile 30 comment "do something with the file" return file] ; I'm also going for readability, otherwise I would have done something like this with the original code |
[unknown: 5] 31-Mar-2009 [13373x2] | John, actually the piece I think I was showing you the first time is what I meant. The series in the second one is actually desired behavior. |
f: func [/local q][q: "blahblahblahblahblah" also q q: none] | |
Geomol 31-Mar-2009 [13375x2] | Is this expected behaviour? >> f: func [/local q][q: "blahblahblahblahblah" also q q: none] >> a: f == "blahblahblahblahblah" >> source f f: func [/local q][q: "blahblahblahblahblah" also q q: none] >> insert a "hmm" == "blahblahblahblahblah" >> source f f: func [/local q][q: "hmmblahblahblahblahblah" also q q: none] >> a: none == none >> source f f: func [/local q][q: "hmmblahblahblahblahblah" also q q: none] |
Izkata, you got a point with your Pread. But it's not a secure function, because it may crash. Let me see, how I would make such a function... | |
[unknown: 5] 31-Mar-2009 [13377x2] | Works for me John |
>> a: f: has [q][q: "blahblahblahblahblah" also q q: none] >> a == "blahblahblahblahblah" | |
Geomol 31-Mar-2009 [13379] | Now do: source f |
[unknown: 5] 31-Mar-2009 [13380x2] | >> f == "blahblahblahblahblah" >> a: f == "blahblahblahblahblah" >> source f f: func [/local q][q: "blahblahblahblahblah" also q q: none] |
what is wrong with it? | |
Geomol 31-Mar-2009 [13382] | So what does your q: none at the end do? It doesn't release any memory. |
[unknown: 5] 31-Mar-2009 [13383] | I believe it does. I believe that q will be freed. |
Geomol 31-Mar-2009 [13384] | You can see, it doesn't this way: >> f: func [/local q][q: "blahblahblahblahblah" also q q: none] >> a: f == "blahblahblahblahblah" >> insert a "more blahblahblahblah" == "blahblahblahblahblah" >> source f f: func [/local q][q: "more blahblahblahblahblahblahblahblahblah" also q q: none] Look at the source of f. Notice the "more blahblah...." |
[unknown: 5] 31-Mar-2009 [13385x5] | Oh, I see. |
then what about this: | |
a: f: has [q][q: copy "blahblahblahblahblah" also q q: none] | |
That last one I forgot is no different then the one I showed you earlier. | |
So I don't know in this case. Is q actually set to none or would it be anyway on the return from the function since it used copy? Dunno. | |
TomBon 31-Mar-2009 [13390] | unfortunatly the same story... does anybody knows why a replace on the second and third also changes the first letter? ^JKSE = %5E/KSE and ^IKSE = %5E-KSE but ^MERV = %5EMERV and therefore okay. probe load replace/all mold "^MERV" #^ "%5E" probe load replace/all mold "^JKSE" #^ "%5E" probe load replace/all mold "^IKSE" #^ "%5E" any advise is highly appreciated... tom |
Geomol 31-Mar-2009 [13391] | Paul, in your last example with copy, the q memory is released, and the string after copy remains. So this actually is a version with something gained. Now I have to think, if I would do it this way. |
Izkata 31-Mar-2009 [13392x3] | Tom: it's not the replace that's doing it... >> "^IKSE" == "^-KSE" >> "^MERV" == "^MERV" >> "^JKSE" == "^/KSE" >> "^IKSE" == "^-KSE" |
but I have no actual answer | |
Well, ^I is a control-i.. and in vim, that inserts a tab. ^- is the tab character in Rebol | |
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