World: r3wp
[!REBOL3-OLD1]
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Ladislav 23-Apr-2009 [13416x3] | re Functor: * in my opinion it does not make sense to initialize static local variables during function call, since they are static and therefore supposed to persist, so the only time suitable for the initialization seems to be the function creation time * the initialization (IMO) can perfectly serve another purpose: all initialized (during function creation) variables shall be static, while the other variables shall be dynamic IMO |
If the terminology does not look good, then we may probably say "persistent" instead of "static" meaning that the values persist during calls unless explicitely changed | |
...but if we use the term "persistent" instead of "static", what would be used instead of "dynamic"? | |
BrianH 23-Apr-2009 [13419] | Dynamic. Local variable capture is half the point of the function, so making the set-words in the body persistent too is a must. |
Anton 23-Apr-2009 [13420x2] | So a functor, with no variables initialized would basically not be a functor. You could evolve a functor with many static variables gradually towards a normal function with no static variables. |
(with Ladislav's initialization idea.) | |
BrianH 23-Apr-2009 [13422] | Ladislav, the reason we are asking about how people use %user.r is so that we make sure that alternate facilities exist to do what people did with %user.r, but safely. The old behavior of %user.r will be going away in R3 for security reasons. However, we have your uses covered by our plans: - Preferences will be handled by the new %user.r -You can include your must-use functions in a module. |
Ladislav 23-Apr-2009 [13423] | making the set-words in the body persistent is a must - let me disagree with this. I think, that the INIT block is a must, since the function cannot initialize the static variables as noted above. OTOH, every variable not initialized during the function creation time should be automatically dynamic, since it does not make much sense to have it uninitialized when using it as static |
BrianH 23-Apr-2009 [13424] | Back to FUNCTOR, that and FUNCT are most often going to be used where the user will only specify the body, not the init or spec. |
Ladislav 23-Apr-2009 [13425] | FUNCT sounds perfectly logical and usable as is, but I really cannot imagine the usage of a persistent value that cannot be initialized at function creation time |
BrianH 23-Apr-2009 [13426] | They could be initialized at first call. We already have facilities to do what you describe. |
Ladislav 23-Apr-2009 [13427] | it simply does not make sense to me |
Anton 23-Apr-2009 [13428] | (You mean *specifically* initialized, with the initialization block; they could be initialized to NONE..) |
Ladislav 23-Apr-2009 [13429] | aha, during first call - how does the user find out which call is the first one? |
BrianH 23-Apr-2009 [13430] | VALUE? |
Anton 23-Apr-2009 [13431] | I agree with Ladislav, using conditional code (eg. using VALUE?) is kind of ugly. |
BrianH 23-Apr-2009 [13432] | Actually, we are going to make a DEFAULT function, but that is one-value-at-a-time until DO/next works. |
Ladislav 23-Apr-2009 [13433] | ...the VALUE? looks inefficient and (IMO) not the proper way. Why should I check always something, that can be done properly just once? |
BrianH 23-Apr-2009 [13434] | Remember that the user won't be specifying the init block most of the time, just the body. Internal code would specify the init. |
Anton 23-Apr-2009 [13435] | You mean the init block would be built automatically from the body block? |
BrianH 23-Apr-2009 [13436] | FUNCT and FUNCTOR are for defining handlers, though FUNCT is also used a lot in mezzanine code. The user would only specify the body block. |
Ladislav 23-Apr-2009 [13437x2] | when I used a static local variable, I always initialized it at the function creation time using my Lfunc. I am sure I wouldn't touch a function with static locals not having proper initialization. |
, but YMMV | |
BrianH 23-Apr-2009 [13439] | We can initialize them to NONE if you like, but having them be unset was deemed more valuable from a debugging standpoint. |
Ladislav 23-Apr-2009 [13440] | well, I do not like NONE (debugging purposes) either |
Anton 23-Apr-2009 [13441] | I see no fault with Ladislav's proposed init block. |
BrianH 23-Apr-2009 [13442] | So far FUNCTOR hasn't really been used, so now is the time to change it if we are going to do so. The variable capture is a must though, since it will be used where the spec can't be specified by the user. |
Anton 23-Apr-2009 [13443] | Oh, now I see what you meant about handlers. |
Ladislav 23-Apr-2009 [13444x3] | yes, that can be used, but I suggest the uninitialized variables to be captured as dynamic, while the initialized be captured as static |
does that make sense? | |
(I mean for your planned use) | |
BrianH 23-Apr-2009 [13447x2] | In general R3 is moving towards specifying handlers as code blocks passed to FUNCT or FUNCTOR with standard specs specified internally. This is their reason for existence. |
BBL, have a meeting :) | |
Anton 23-Apr-2009 [13449x2] | So how would a user, when specifying a handler, which becomes the functor body, specify that a given variable is to be static, and that another variable is to be dynamic? |
If FUNCTOR scans the given body block and treats all variables the same, then that control is lost by the user. Are we happy to lose that control? Maybe FUNCTOR should have the initialization block like Ladislav suggests, and a more specific "handler-func" function be created for the specific handler use Brian is talking about? | |
Ladislav 23-Apr-2009 [13451] | if you are asking me, then the static variables may be captured from the INIT block, all other from the body, but it looks, that BrianH intended to have all variables static in a Functor, except for the variables from the SPEC block |
Anton 23-Apr-2009 [13452x2] | Why couldn't the init block be inside the body block, in first position? |
(.... maybe not such a good idea..) | |
Ladislav 23-Apr-2009 [13454] | yes, then it might be better to use the same approach as the MAKE funtion in R3 seems to use |
Anton 23-Apr-2009 [13455] | I need to sleep on that... |
[unknown: 5] 23-Apr-2009 [13456] | Ladislav, great to see you back!!! Now, tell us where have you been and why gone so long? |
BrianH 23-Apr-2009 [13457x4] | One thing to remember is that these function-building functions will be called a lot, so fast-and-simple is better than complex. |
Ladislav, strangely enough there are also persistent words defined for the words in the spec, if they are set with set-words in the body. You can access them through self. It's just that the spec takes binding priority, so direct access to the words in the spec will be bound to the spec. There are many potential advantages to this, but the main reason this was done was speed. | |
FUNCT works well, but is too slow and has too much overhead. We already had to make one error go away to remove the screen for spec words overhead (see bug#717), but it still has the overhead of a temporary object which we haven't removed yet (see bug#544). If you had FUNCTOR work the way you say, you would have to somehow distinguish words in the persistant object (as specified with init) from words that should be made into locals, which would add back the same overhead that the change referred to in bug#717 got rid of, as REBOL code. This would make FUNCTOR have much less performance than the equivalent code: CONTEXT [var1: 'blah ... SET 'func1 FUNC [...] [...]] | |
In general we are trying to deal with the problem in R2 where many functions were optimized away in high-performance code, so they end up being a waste of space. Many former mezzanines are now native, and many others are changed to make their overall usage more efficient. It's a balance. | |
Steeve 23-Apr-2009 [13461] | Currently, i have a crash when i start the chat with r3-a48 under Vista. Obviously, i can't see what is the bug, And when i try with the previous version i got (a42) i got this error: --- Note: checking for new messages *** RebDev Error: server connection failed, is server down? (server-failed) ** Script error: cause-error-here has no value ** Where: error if unless request-serve if check-msgs check-new make context do catch applier do try chat ** Near: error result We have no way to return in a safe situation and can't guess what is the bug indeed. Is Carl aware of that problem, i didn't see anything related to a crash of a48 when starting the chat ? |
BrianH 23-Apr-2009 [13462x2] | try again |
It works for me. Does this happen every time? | |
Steeve 23-Apr-2009 [13464x2] | Not anymore, but it was like that during 1 hour at least |
damit, i tried during one hour and just when you say: try again, it works.... | |
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