Re: [Gambas-user] static const?
Fabián Flores Vadell ha scritto: 2010/4/13 Jussi Lahtinenjussi.lahti...@gmail.com: Just in case: REPEAT b = TabStrip3.Count ' In fact, this does nothing usefull INC a UNTIL a TabStrip3.Count OR TabStrip3[a].Caption = IdCaption This doesn't make same functionality. I can't resist to add my mis-contribute... Back to the beginning: a CONST declaration is something that uses no memory, so it can not have instances, and hence it can not be STATIC. The C language, in facts, does not even have CONSTs - it goes with #define. So, it would be correct to forbid STATIC when declaring CONSTs. On the other hand, a CONST is always static, because the effective data it describes reside in a memory outside the program - they reside in the compiler memory. About the cycles WHILE, FOR, REPEAT and so on, I think the statements BREAK and CONTINUE are very useful (I would add a third statement: RESTART): they permit a finer control and many times they are clearer than complex tests. . Your example only has two test, against COUNT and the CAPTION. What kind of test would you write if the conditions were 15? Perhaps concatenated (I mean, some test are only meaningful when other conditions are met). Finally, your last lines of code do not work: PRIVATE FUNCTION ScanTab(IdCaption AS String) AS Byte DIM a AS Byte = 0 WHILE (a TabStrip1.Count - 1) AND (TabStrip1[a].Text IdCaption) INC a WEND RETURN IF(TabStrip1[a].Caption = IdCaption, a, -1) END Suppose you have a tabstrip with three tabs, and last, Tabstrip1[2] has the caption we want. In the first cycle, we test Tabstrip1[0]: does not match, and a turns 1 In the secon cycle, we test tabstrip1[1]: does not match and a turns 2 The third cycle does not get executed - a is 2, which is not less than 3-1 (it is equal). Moreover, your algorithm does a double test on caption, which could be avoided. Doing an additional test is not an important thing if the test is quick and the routine is called not too much often. What if the routine is called millions time, or the test is more heavy? About not using RETURN or BREAK inside cycles, we must think at different kind of cycles. The WHILE and alike, where no variables are directly involved in the cycle declaration, never have problems - the semantic of the declaration does not imply anything about variable allocation. In the FOR cycles instead, other languages can do strange things, both on allocation and code optimization, so it is effectively a bad idea to fiddle with the loop control variable; in other languages this is not stressed the same way (basic, for example), but actually is, at least, ugly. It seems to me that you have said that an exception would be the FOR EACH cycle... why? Regards, Doriano -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
Re: [Gambas-user] Showing the Form's Gui
Ricardo: Could you post a example of your open forms method? I'm very interested on it. It sound like something I have searching for a long time. Gracias Jorge 2010/4/13 Ricardo Díaz Martín oceanosoftlapa...@gmail.com If It can help to someone, this is I always do: When I'm going to open a form, I always call my own OpenForm(FormName as String, Parameters as String) sub. This sub is not inside the form I'm going to open. It's a public sub that's is inside a utilities module. OpenForm() sub create new object with the form (f.e. FRMMain) and put its reference inside a public collection called OpenedForms. Before to show form to the user, I show other form with a progress bar and a label showing Loading... and I'm going executing SQL, show/hid controls, etc... with no show anything. If there are a fixed steps to data load, I updated progress bar and when load process finish I show the form. I use this in all my apps (since lot of years when I never eared about gambas and I was programing in VB, Access, Java, etc...) and for me is the best option. For sure there is a lot of ways to do this. Regards, Ricardo Díaz 2010/4/13 Doriano Blengino doriano.bleng...@fastwebnet.it Fabien Bodard ha scritto: 2010/4/13 Doriano Blengino doriano.bleng...@fastwebnet.it: Fabien Bodard ha scritto: just remember to put a flag to say when the data are loaded ! What would be the reason for this flag? if the form is showed and the data not accessible ? Really, there could be a problem if the user clicks a button 50 ms after the button (and the whole form) is visible. A remote possibility, and application-dependent. But I know users enough to imagine that someone could do it... :-) Reducing the interval of the one-shot timer can help, but does not solve (interval=0 could?). The better way is to disable actions the user could do with invalid data (application dependent: who says that the form is intended to receive clicks?), and perhaps add a nice label stating Loading data, please wait... and so on. Anyway, the flag is the worse solution. Supposing you use a flag, and the user clicks or types too fast, what would you do? A Message.Info(You clicked too fast. Go to have a coffee and come back later.)? :-) Better to disable some controls, so the user is informed before; in addition, controls are already global variables which carry informations with them. Well, this is my opinion - I hate to duplicate informations around, but someone else on this list, time ago, said never use the GUI to store information. The problem with global (or class) variables is that you can forget them more easily than some property of a visible control. Regards, Doriano -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
Re: [Gambas-user] Showing the Form's Gui
Hi Jorge, While we wait to see if Ricardo wants to share his open forms method (I'm also interested to see it), here's some code I have used before (see attachment) where the opening/closing of forms is handled by a module, which I've called RunController. The module is set as the Startup Class (normally that's by default the first Form you declare I think) and must have a Main() method. Right-clicking on the module brings up a context menu where you can click on the Startup Class checkbox. You can see that the RunController module can decide when it opens each form (so you could have some long-running data extraction go on in the background), and handles events raised by the forms (in conjunction with Attach, making sure RunController actually gets the events). One of the first things RunController does is to decide should I first open up the settings form (no Dragons defined yet)? or should I show the main form already (at least one Dragon exists in settings)?: IF theSettings.getDragonCount() = 0 THEN settingsFrm = NEW SettingsForm settingsFrm.Show Object.Attach(settingsFrm, ME, SettingsFrm) ELSE Logger.logMessage(RunController.Main() dragon found, so starting Remote Control, FALSE) remC = NEW RemoteControl remC.Show Object.Attach(remC, ME, Remote) tCop = NEW TrafficCop tCop.show Object.Attach(tCop, ME, Cop) END IF One limitation of my approach is that you need to explicitly declare each form you're going to use up-front, so I'm interested to see if Ricardo's approach avoids that. Regards, Caveat On Wed, 2010-04-14 at 11:59 +0200, Jorge Carrión wrote: Ricardo: Could you post a example of your open forms method? I'm very interested on it. It sound like something I have searching for a long time. Gracias Jorge 2010/4/13 Ricardo Díaz Martín oceanosoftlapa...@gmail.com If It can help to someone, this is I always do: When I'm going to open a form, I always call my own OpenForm(FormName as String, Parameters as String) sub. This sub is not inside the form I'm going to open. It's a public sub that's is inside a utilities module. OpenForm() sub create new object with the form (f.e. FRMMain) and put its reference inside a public collection called OpenedForms. Before to show form to the user, I show other form with a progress bar and a label showing Loading... and I'm going executing SQL, show/hid controls, etc... with no show anything. If there thrownare a fixed steps to data load, I updated progress bar and when load process finish I show the form. I use this in all my apps (since lot of years when I never eared about gambas and I was programing in VB, Access, Java, etc...) and for me is the best option. For sure there is a lot of ways to do this. Regards, Ricardo Díaz 2010/4/13 Doriano Blengino doriano.bleng...@fastwebnet.it Fabien Bodard ha scritto: 2010/4/13 Doriano Blengino doriano.bleng...@fastwebnet.it: Fabien Bodard ha scritto: just remember to put a flag to say when the data are loaded ! What would be the reason for this flag? if the form is showed and the data not accessible ? Really, there could be a problem if the user clicks a button 50 ms after the button (and the whole form) is visible. A remote possibility, and application-dependent. But I know users enough to imagine that someone could do it... :-) Reducing the interval of the one-shot timer can help, but does not solve (interval=0 could?). The better way is to disable actions the user could do with invalid data (application dependent: who says that the form is intended to receive clicks?), and perhaps add a nice label stating Loading data, please wait... and so on. Anyway, the flag is the worse solution. Supposing you use a flag, and the user clicks or types too fast, what would you do? A Message.Info(You clicked too fast. Go to have a coffee and come back later.)? :-) Better to disable some controls, so the user is informed before; in addition, controls are already global variables which carry informations with them. Well, this is my opinion - I hate to duplicate informations around, but someone else on this list, time ago, said never use the GUI to store information. The problem with global (or class) variables is that you can forget them more easily than some property of a visible control. Regards, Doriano -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net
Re: [Gambas-user] static const?
The C language, in facts, does not even have CONSTs - it goes with
#define. So, it would be correct to forbid STATIC when declaring CONSTs.
Surely this is not correct. ANSI C uses const, and C++ also uses the
const keyword.
#define (a preprocessor directive) is a relic from old C, and const is
now recommended use instead.
Also, it would be correct to use static with const, the line below would
be correct use.
static const int daysPerMonth[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
Having said that, The original question was not about C, I think Fabian
was simply asking about the scope of constants in classes (in Gambas)
Regards
Les Hardy
--
Download Intel#174; Parallel Studio Eval
Try the new software tools for yourself. Speed compiling, find bugs
proactively, and fine-tune applications for parallel performance.
See why Intel Parallel Studio got high marks during beta.
http://p.sf.net/sfu/intel-sw-dev
___
Gambas-user mailing list
Gambas-user@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/gambas-user
Re: [Gambas-user] static const?
Les Hardy ha scritto:
The C language, in facts, does not even have CONSTs - it goes with
#define. So, it would be correct to forbid STATIC when declaring CONSTs.
Surely this is not correct. ANSI C uses const, and C++ also uses the
const keyword.
#define (a preprocessor directive) is a relic from old C, and const is
now recommended use instead.
Surely, according to http://www.ericgiguere.com/articles/ansi-c-summary.html
The declaration:
enum colours { RED, BLUE, GREEN };
would declare colours as an enumeration tag representing the integer
constants RED, BLUE and GREEN. These enumeration constants are given
integer values starting at 0 and increasing by 1 with each identifier.
An enumeration constant may be used wherever an integer is expected.
The following is equivalent to the above enumerated type:
#define RED 0
#define BLUE 1
#define GREEN 2
Moreover, from http://tigcc.ticalc.org/doc/keywords.html
_const_
*Makes variable value or pointer parameter unmodifiable.*
When |const| is used with a variable, it uses the following syntax:
const/variable-name/ [ =/value/];
In this case, the |const| modifier allows you to assign an initial
value to a variable that cannot later be changed by the program. For
example,
const my_age = 32;
Any assignments to |'my_age'| will result in a compiler error.
However, such declaration is quite different than using
#define my_age 32
In the first case, the compiler allocates a memory for |'my_age'| and
stores the initial value 32 there, but it will not allow any later
assignment to this variable. But, in the second case, all occurences
of |'my_age'| are simply replaced with 32 by the preprocessor
http://tigcc.ticalc.org/doc/cpp.html, and no memory will be
allocated for it.
You perhaps refer to const modifier, which is different from declaring
a constant, like in
public:
WinEDA_VertexCtrl( wxWindow* parent, const wxString title,
wxBoxSizer* BoxSizer, int units, int
internal_unit );
Also, it would be correct to use static with const, the line below would
be correct use.
static const int daysPerMonth[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
In this case - talking about C and not C++:
|static| tells that a function or data element is only known within
the scope of the current compile. In addition, if you use the |static|
keyword with a variable that is local to a function, it allows the
last value of the variable to be preserved between successive calls to
that function.
const says that data is not modifiable, so static would say the same
thing. Note also the ambiguity of the keyword when applied to data
global to a module, and data local to a function - the same keyword does
two very different things.
Having said that, The original question was not about C, I think Fabian
was simply asking about the scope of constants in classes (in Gambas)
Uhm... is it forbidden to cite other languages to better explain a
concept? So why you cited C++?
Anyway, you are right, the original question was about scope. In gambas
scope is governed by PRIVATE and PUBLIC. Full stop.
If you feel that my reply is a little hurting, excuse me; it is because
your reply seemed hurting to me. Prove to me that I am wrong and I will
publicly apologize.
Regards,
Doriano
--
Download Intel#174; Parallel Studio Eval
Try the new software tools for yourself. Speed compiling, find bugs
proactively, and fine-tune applications for parallel performance.
See why Intel Parallel Studio got high marks during beta.
http://p.sf.net/sfu/intel-sw-dev
___
Gambas-user mailing list
Gambas-user@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/gambas-user
Re: [Gambas-user] Showing the Form's Gui
Caveat: Thank you very much for you module. I'll read it carefully. Regards 2010/4/14 Caveat gam...@caveat.demon.co.uk Hi Jorge, While we wait to see if Ricardo wants to share his open forms method (I'm also interested to see it), here's some code I have used before (see attachment) where the opening/closing of forms is handled by a module, which I've called RunController. The module is set as the Startup Class (normally that's by default the first Form you declare I think) and must have a Main() method. Right-clicking on the module brings up a context menu where you can click on the Startup Class checkbox. You can see that the RunController module can decide when it opens each form (so you could have some long-running data extraction go on in the background), and handles events raised by the forms (in conjunction with Attach, making sure RunController actually gets the events). One of the first things RunController does is to decide should I first open up the settings form (no Dragons defined yet)? or should I show the main form already (at least one Dragon exists in settings)?: IF theSettings.getDragonCount() = 0 THEN settingsFrm = NEW SettingsForm settingsFrm.Show Object.Attach(settingsFrm, ME, SettingsFrm) ELSE Logger.logMessage(RunController.Main() dragon found, so starting Remote Control, FALSE) remC = NEW RemoteControl remC.Show Object.Attach(remC, ME, Remote) tCop = NEW TrafficCop tCop.show Object.Attach(tCop, ME, Cop) END IF One limitation of my approach is that you need to explicitly declare each form you're going to use up-front, so I'm interested to see if Ricardo's approach avoids that. Regards, Caveat On Wed, 2010-04-14 at 11:59 +0200, Jorge Carrión wrote: Ricardo: Could you post a example of your open forms method? I'm very interested on it. It sound like something I have searching for a long time. Gracias Jorge 2010/4/13 Ricardo Díaz Martín oceanosoftlapa...@gmail.com If It can help to someone, this is I always do: When I'm going to open a form, I always call my own OpenForm(FormName as String, Parameters as String) sub. This sub is not inside the form I'm going to open. It's a public sub that's is inside a utilities module. OpenForm() sub create new object with the form (f.e. FRMMain) and put its reference inside a public collection called OpenedForms. Before to show form to the user, I show other form with a progress bar and a label showing Loading... and I'm going executing SQL, show/hid controls, etc... with no show anything. If there thrownare a fixed steps to data load, I updated progress bar and when load process finish I show the form. I use this in all my apps (since lot of years when I never eared about gambas and I was programing in VB, Access, Java, etc...) and for me is the best option. For sure there is a lot of ways to do this. Regards, Ricardo Díaz 2010/4/13 Doriano Blengino doriano.bleng...@fastwebnet.it Fabien Bodard ha scritto: 2010/4/13 Doriano Blengino doriano.bleng...@fastwebnet.it: Fabien Bodard ha scritto: just remember to put a flag to say when the data are loaded ! What would be the reason for this flag? if the form is showed and the data not accessible ? Really, there could be a problem if the user clicks a button 50 ms after the button (and the whole form) is visible. A remote possibility, and application-dependent. But I know users enough to imagine that someone could do it... :-) Reducing the interval of the one-shot timer can help, but does not solve (interval=0 could?). The better way is to disable actions the user could do with invalid data (application dependent: who says that the form is intended to receive clicks?), and perhaps add a nice label stating Loading data, please wait... and so on. Anyway, the flag is the worse solution. Supposing you use a flag, and the user clicks or types too fast, what would you do? A Message.Info(You clicked too fast. Go to have a coffee and come back later.)? :-) Better to disable some controls, so the user is informed before; in addition, controls are already global variables which carry informations with them. Well, this is my opinion - I hate to duplicate informations around, but someone else on this list, time ago, said never use the GUI to store information. The problem with global (or class) variables is that you can forget them more easily than some property of a visible control. Regards, Doriano -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel
Re: [Gambas-user] static const?
2010/4/14 Doriano Blengino doriano.bleng...@fastwebnet.it: Back to the beginning: a CONST declaration is something that uses no memory, so it can not have instances, and hence it can not be STATIC. On the other hand, a CONST is always static, because the effective data it describes reside in a memory outside the program - they reside in the compiler memory. Thanks Doriano. I understand that. My question was caused by the fact that the compiler allows use the keyword STATIC in the declaration of constants, even though the online help and a very basic logical reasoning indicate that use the keyword STATIC is unnecesary in this situation About the cycles WHILE, FOR, REPEAT and so on, I think the statements BREAK and CONTINUE are very useful (I would add a third statement: RESTART): they permit a finer control and many times they are clearer than complex tests. You do not give arguments to support your opinion. Can you give me some examples? I think, that these can be obvious for you, but not for me. Your example only has two test, against COUNT and the CAPTION. What kind of test would you write if the conditions were 15? Perhaps concatenated (I mean, some test are only meaningful when other conditions are met). Assign the results of logical expressions to Boolean variables, it is often the way to manage the complexity of conditionals expressions. And in the loops, to use these variables instead of those logical expressions. But I think that you are knowing well this, and you points to the performance of programs. If so, my answer is that the performance isn't a priority in many types of programs, and the evaluation of logical expressions have a little cost in comparation with other operations (I/O, compression, among many others). Finally, your last lines of code do not work: Yes, it works. PRIVATE FUNCTION ScanTab(IdCaption AS String) AS Byte DIM a AS Byte = 0 WHILE (a TabStrip1.Count - 1) AND (TabStrip1[a].Text IdCaption) INC a WEND RETURN IF(TabStrip1[a].Caption = IdCaption, a, -1) END The third cycle does not get executed - a is 2, which is not less than 3-1 (it is equal). That's irrelevant because the external comprobation (the logical expression in the return sentence) Moreover, your algorithm does a double test on caption, which could be avoided. I think that the second test can't to be avoided. If it isn't put out the loop, you have to put into the loop. The reason for include the test (TabStrip1[a].Text IdCaption) in conditional expression is only stop the loop if there's match before get the last item. I think that this code can to write in many ways, but with no significant variations. How would you do? Doing an additional test is not an important thing if the test is quick and the routine is called not too much often. What if the routine is called millions time, or the test is more heavy? I think that the computational cost of evaluate complex logical expressions, generally is insignificant. But if not, then the first thing to be considerated is the language to use, and I see few alternatives: assembler, C, C++, someone else; the second thing is the many optimizations to do. But, what kind the system would be? One that is not possible to do with Gambas. About not using RETURN or BREAK inside cycles, we must think at different kind of cycles. The WHILE and alike, where no variables are directly involved in the cycle declaration, never have problems - the semantic of the declaration does not imply anything about variable allocation. In the FOR cycles instead, other languages can do strange things, both on allocation and code optimization, so it is effectively a bad idea to fiddle with the loop control variable; in other languages this is not stressed the same way (basic, for example), but actually is, at least, ugly. Yep, but I not was thinking in possible collateral effects, derived from implementation of language. (To those, the corresponding compiler would let in evidence, or would become a logical error isn't very difficult to detect and correct). I was thinking in conceptuals implications. This conceptuals implications derives in to use of the language resources in any ways, instead to use them in the correct situations. It seems to me that you have said that an exception would be the FOR EACH cycle... why? FOR EACH really iterates through all items, so there's only way to stop the loop when it's goal is achieved, is by the BREAK sentence used in a conditonal sentence inside the loop. But it might think that if it is necessary to do this, then the iterative structure FOR EACH is not adequate. And I hope that my very ugly english, does not cause tears. -- Fabián Flores Vadell www.speedbooksargentina.blogspot.com -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively,
Re: [Gambas-user] static const?
If you feel hurt I am sorry for that, it was not my intention to hurt
you, and I have no wish to prove you wrong.
I do still stand by my statement.
Regards
Les Hardy
Doriano Blengino wrote:
Les Hardy ha scritto:
The C language, in facts, does not even have CONSTs - it goes with
#define. So, it would be correct to forbid STATIC when declaring CONSTs.
Surely this is not correct. ANSI C uses const, and C++ also uses the
const keyword.
#define (a preprocessor directive) is a relic from old C, and const is
now recommended use instead.
Surely, according to http://www.ericgiguere.com/articles/ansi-c-summary.html
The declaration:
enum colours { RED, BLUE, GREEN };
would declare colours as an enumeration tag representing the integer
constants RED, BLUE and GREEN. These enumeration constants are given
integer values starting at 0 and increasing by 1 with each identifier.
An enumeration constant may be used wherever an integer is expected.
The following is equivalent to the above enumerated type:
#define RED 0
#define BLUE 1
#define GREEN 2
Moreover, from http://tigcc.ticalc.org/doc/keywords.html
_const_
*Makes variable value or pointer parameter unmodifiable.*
When |const| is used with a variable, it uses the following syntax:
const/variable-name/ [ =/value/];
In this case, the |const| modifier allows you to assign an initial
value to a variable that cannot later be changed by the program. For
example,
const my_age = 32;
Any assignments to |'my_age'| will result in a compiler error.
However, such declaration is quite different than using
#define my_age 32
In the first case, the compiler allocates a memory for |'my_age'| and
stores the initial value 32 there, but it will not allow any later
assignment to this variable. But, in the second case, all occurences
of |'my_age'| are simply replaced with 32 by the preprocessor
http://tigcc.ticalc.org/doc/cpp.html, and no memory will be
allocated for it.
You perhaps refer to const modifier, which is different from declaring
a constant, like in
public:
WinEDA_VertexCtrl( wxWindow* parent, const wxString title,
wxBoxSizer* BoxSizer, int units, int
internal_unit );
Also, it would be correct to use static with const, the line below would
be correct use.
static const int daysPerMonth[13] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
In this case - talking about C and not C++:
|static| tells that a function or data element is only known within
the scope of the current compile. In addition, if you use the |static|
keyword with a variable that is local to a function, it allows the
last value of the variable to be preserved between successive calls to
that function.
const says that data is not modifiable, so static would say the same
thing. Note also the ambiguity of the keyword when applied to data
global to a module, and data local to a function - the same keyword does
two very different things.
Having said that, The original question was not about C, I think Fabian
was simply asking about the scope of constants in classes (in Gambas)
Uhm... is it forbidden to cite other languages to better explain a
concept? So why you cited C++?
Anyway, you are right, the original question was about scope. In gambas
scope is governed by PRIVATE and PUBLIC. Full stop.
If you feel that my reply is a little hurting, excuse me; it is because
your reply seemed hurting to me. Prove to me that I am wrong and I will
publicly apologize.
Regards,
Doriano
--
Download Intel#174; Parallel Studio Eval
Try the new software tools for yourself. Speed compiling, find bugs
proactively, and fine-tune applications for parallel performance.
See why Intel Parallel Studio got high marks during beta.
http://p.sf.net/sfu/intel-sw-dev
___
Gambas-user mailing list
Gambas-user@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/gambas-user
Re: [Gambas-user] Showing the Form's Gui
This is a gb2 project example about we were talking. Excuse me but is in Spanish (I got no enough time to do something better than this). I was cutting/pasting for a while and deleting extra thinks to get this example. If not exactly the same I use but I hope It can help you. Caveat, I need an explicit form declaration too because gambas can't create a object by name (or I think so). Please note it's only an example. Regards, Ricardo Díaz El 14 de abril de 2010 18:48, Jorge Carrión sho...@gmail.com escribió: Caveat: Thank you very much for you module. I'll read it carefully. Regards 2010/4/14 Caveat gam...@caveat.demon.co.uk Hi Jorge, While we wait to see if Ricardo wants to share his open forms method (I'm also interested to see it), here's some code I have used before (see attachment) where the opening/closing of forms is handled by a module, which I've called RunController. The module is set as the Startup Class (normally that's by default the first Form you declare I think) and must have a Main() method. Right-clicking on the module brings up a context menu where you can click on the Startup Class checkbox. You can see that the RunController module can decide when it opens each form (so you could have some long-running data extraction go on in the background), and handles events raised by the forms (in conjunction with Attach, making sure RunController actually gets the events). One of the first things RunController does is to decide should I first open up the settings form (no Dragons defined yet)? or should I show the main form already (at least one Dragon exists in settings)?: IF theSettings.getDragonCount() = 0 THEN settingsFrm = NEW SettingsForm settingsFrm.Show Object.Attach(settingsFrm, ME, SettingsFrm) ELSE Logger.logMessage(RunController.Main() dragon found, so starting Remote Control, FALSE) remC = NEW RemoteControl remC.Show Object.Attach(remC, ME, Remote) tCop = NEW TrafficCop tCop.show Object.Attach(tCop, ME, Cop) END IF One limitation of my approach is that you need to explicitly declare each form you're going to use up-front, so I'm interested to see if Ricardo's approach avoids that. Regards, Caveat On Wed, 2010-04-14 at 11:59 +0200, Jorge Carrión wrote: Ricardo: Could you post a example of your open forms method? I'm very interested on it. It sound like something I have searching for a long time. Gracias Jorge 2010/4/13 Ricardo Díaz Martín oceanosoftlapa...@gmail.com If It can help to someone, this is I always do: When I'm going to open a form, I always call my own OpenForm(FormName as String, Parameters as String) sub. This sub is not inside the form I'm going to open. It's a public sub that's is inside a utilities module. OpenForm() sub create new object with the form (f.e. FRMMain) and put its reference inside a public collection called OpenedForms. Before to show form to the user, I show other form with a progress bar and a label showing Loading... and I'm going executing SQL, show/hid controls, etc... with no show anything. If there thrownare a fixed steps to data load, I updated progress bar and when load process finish I show the form. I use this in all my apps (since lot of years when I never eared about gambas and I was programing in VB, Access, Java, etc...) and for me is the best option. For sure there is a lot of ways to do this. Regards, Ricardo Díaz 2010/4/13 Doriano Blengino doriano.bleng...@fastwebnet.it Fabien Bodard ha scritto: 2010/4/13 Doriano Blengino doriano.bleng...@fastwebnet.it: Fabien Bodard ha scritto: just remember to put a flag to say when the data are loaded ! What would be the reason for this flag? if the form is showed and the data not accessible ? Really, there could be a problem if the user clicks a button 50 ms after the button (and the whole form) is visible. A remote possibility, and application-dependent. But I know users enough to imagine that someone could do it... :-) Reducing the interval of the one-shot timer can help, but does not solve (interval=0 could?). The better way is to disable actions the user could do with invalid data (application dependent: who says that the form is intended to receive clicks?), and perhaps add a nice label stating Loading data, please wait... and so on. Anyway, the flag is the worse solution. Supposing you use a flag, and the user clicks or types too fast, what would you do? A Message.Info(You clicked too fast. Go to have a coffee and come back later.)? :-) Better to disable some controls, so the user is informed before; in addition, controls are already global
Re: [Gambas-user] static const?
Fabián Flores Vadell ha scritto: 2010/4/14 Doriano Blenginodoriano.bleng...@fastwebnet.it: Back to the beginning: a CONST declaration is something that uses no memory, so it can not have instances, and hence it can not be STATIC. Thanks Doriano. I understand that. My question was caused by the fact that the compiler allows use the keyword STATIC in the declaration of constants, even though the online help and a very basic logical reasoning indicate that use the keyword STATIC is unnecesary in this situation And here we return on your idea about a good compiler - and it is mine idea too. A good compiler should be very precise about things that have sense, and can be done, and things that can not be done, or have no meaning. In this respect, it is a nonsense to let the user write a CONST STATIC. But compilers sometimes must keep compatibility with other, older, compilers. So, in this case, may be that VB(tm) was accepting this, and so does gambas. But I don't know VB(tm). Anyway, this issue is harmless, so I don't see it as a big problem. About the cycles WHILE, FOR, REPEAT and so on, I think the statements BREAK and CONTINUE are very useful (I would add a third statement: RESTART): they permit a finer control and many times they are clearer than complex tests. You do not give arguments to support your opinion. Can you give me some examples? I think, that these can be obvious for you, but not for me. First of all, I must say that I see your point. May be that all the issue is about personal style. But I did a quick research in my sources to let you see some example. I have little code in gambas - I use a lot C, about which I could have many examples but, as stated by someone other, it is forbidden to talk about C... First example. I store some bookmarks in a file by using the Settings class. Every bookmark is stored with a name like Bmark1, Bmark2 and so on, but I don't know how many of them are in the file. I know when there are no more values, instead. So the routine is the following: i = 1 DO st = settings[Bmark i, ] IF st = THEN BREAK men = NEW Menu(mnBooks) AS chgBook men.Caption = st INC i LOOP Now, to understand if there are more bookmarks to read, I must try to read it. If the value is NULL, then the job is finished. Clearly, a FOR-NEXT is no good (or, one can write a for-next from 1 to 1000... misleading...). I could break out the loop using a logic variable, but this way I save a variable. Or I could test the variable in the loop construct, like this: i = 1 DO st = settings[Bmark i, ] if st then men = NEW Menu(mnBooks) AS chgBook men.Caption = st ENDIF INC i while st but, as you see, there are TWO tests instead of one, and there is an added line of code. May be that I am missing something, but the BREAK instruction is really useful here. The second example is a textual search on a treeview. If the user types some text, the selection is moved on the next item beginning with that text. If no more items satisfy the criterium, the search must start again at the top, but only once. So the code (there is a ME.MoveBelow() just before this code, I omitted it for simplicity): i = Len(searchstring) FOR tries = 1 TO 2' to search again from the top DO IF Upper(Left(ME.item.Text, i)) = searchstring THEN ' found item RETURN ENDIF IF ME.MoveBelow() THEN BREAK LOOP ME.MoveFirst NEXT Here, the FOR-NEXT is a quick way to execute some code for no more than two times... Again, I could have used a variable to store the result of the test, but I saved it... And again this is not, perhaps, the best code you can see around - but it works, and it is reasonably fast and short. Your example only has two test, against COUNT and the CAPTION. What kind of test would you write if the conditions were 15? Perhaps concatenated (I mean, some test are only meaningful when other conditions are met). Assign the results of logical expressions to Boolean variables, it is often the way to manage the complexity of conditionals expressions. And in the loops, to use these variables instead of those logical expressions. But I think that you are knowing well this, and you points to the performance of programs. If so, my answer is that the performance isn't a priority in many types of programs, and the evaluation of logical expressions have a little cost in comparation with other operations (I/O, compression, among many others). I agree, and partly not. I think that clearness and beatiful code is to prefer against speed, but only when speed is not an issue. In the text-search example speed *is* an issue. Never tried to open a directory with some 3 files in it, and perform a textual search? KDE solves elegantly... it does textual search *only* if the sort order is by name.
Re: [Gambas-user] Showing the Form's Gui
i don't know if richard want the user to be able to do anything on the showed form before the tatal loading ... the better way will be to do the loading in the timer by use the timer.trigger function the form .enabled will be set to false and the timer just set the form.enabled to true when the loading is ok when you set a contained enabled to false all the form content is set to false too. So the form is showed but not editable. 2010/4/13 Doriano Blengino doriano.bleng...@fastwebnet.it: Fabien Bodard ha scritto: 2010/4/13 Doriano Blengino doriano.bleng...@fastwebnet.it: Fabien Bodard ha scritto: just remember to put a flag to say when the data are loaded ! What would be the reason for this flag? if the form is showed and the data not accessible ? Really, there could be a problem if the user clicks a button 50 ms after the button (and the whole form) is visible. A remote possibility, and application-dependent. But I know users enough to imagine that someone could do it... :-) Reducing the interval of the one-shot timer can help, but does not solve (interval=0 could?). The better way is to disable actions the user could do with invalid data (application dependent: who says that the form is intended to receive clicks?), and perhaps add a nice label stating Loading data, please wait... and so on. Anyway, the flag is the worse solution. Supposing you use a flag, and the user clicks or types too fast, what would you do? A Message.Info(You clicked too fast. Go to have a coffee and come back later.)? :-) Better to disable some controls, so the user is informed before; in addition, controls are already global variables which carry informations with them. Well, this is my opinion - I hate to duplicate informations around, but someone else on this list, time ago, said never use the GUI to store information. The problem with global (or class) variables is that you can forget them more easily than some property of a visible control. Regards, Doriano -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
Re: [Gambas-user] static const?
Errata corrige: Finally, your last lines of code do not work: Yes, it works. PRIVATE FUNCTION ScanTab(IdCaption AS String) AS Byte DIM a AS Byte = 0 WHILE (aTabStrip1.Count - 1) AND (TabStrip1[a].Text IdCaption) INC a WEND RETURN IF(TabStrip1[a].Caption = IdCaption, a, -1) END The third cycle does not get executed - a is 2, which is not less than 3-1 (it is equal). That's irrelevant because the external comprobation (the logical expression in the return sentence) May be that I am missing something, but... how can you say that it works if it omits to test the last item? Time later, driving to home and still thinking about this routine, I finally recalled what you wanted to say with comprobation. Yes, you are right - your code works. If I would have payed more attention to the routine, I would have noticed. But, stupidly, I concentrated only on the cycle, noting that it was missing a test on the last item. That last item is managed by the last test before exiting. Still I don't like this routine. What happens if TabStrip1.Count=0 (emtpy tabstrip)? Ok, now I'am home, it's late - so good night to everybody (in Europe, of course). Regards, -- Doriano Blengino Listen twice before you speak. This is why we have two ears, but only one mouth. -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
Re: [Gambas-user] There are errors in the class Key , and in the events KeyPress / KeyRelease?
Key.Text is not guaranteed to be set during a KeyRelease. (Do you means readed? Ok, you are look at from compiler dev perspective. Right?) Why it's in that way? Because Qt loses some information needed by the KeyRelease event when some compound keys are used. -- Benoît Minisini -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
Re: [Gambas-user] static const?
2010/4/14 Doriano Blengino doriano.bleng...@fastwebnet.it: And here we return on your idea about a good compiler - and it is mine idea too. I don't want judge if the Gambas compiler is good or not, I feel that I don't have the knowledge or experience required for do that. But, I shared with you about the taste for a compiler that to say at programmer: This is right. That's not a good idea. First of all, I must say that I see your point. May be that all the issue is about personal style. Yes, I have to admit that the style surely have influence in the beauty criteria. But I did a quick research in my sources to let you see some example. I have little code in gambas - I use a lot C, about which I could have many examples but, as stated by someone other, it is forbidden to talk about C... Ha! Is forbidden if you want that I can understand you. That is true :) First example. I store some bookmarks in a file by using the Settings class. Every bookmark is stored with a name like Bmark1, Bmark2 and so on, but I don't know how many of them are in the file. I know when there are no more values, instead. So the routine is the following: i = 1 DO st = settings[Bmark i, ] IF st = THEN BREAK men = NEW Menu(mnBooks) AS chgBook men.Caption = st INC i LOOP ... I could break out the loop using a logic variable, but this way I save a variable. Or I could test the variable in the loop construct, like this: ... but, as you see, there are TWO tests instead of one, and there is an added line of code. I don't agree the criteria for saving one variable or one expresion if it is not justified. May be that I am missing something, but the BREAK instruction is really useful here. I don't say that BREAK (and other sentences) haven't utility, but that isn't strictly necessary (perhaps I said unnecesary and this word may be incorrect). The second example is a textual search on a treeview. If the user types some text, the selection is moved on the next item beginning with that text. If no more items satisfy the criterium, the search must start again at the top, but only once. So the code (there is a ME.MoveBelow() just before this code, I omitted it for simplicity): i = Len(searchstring) FOR tries = 1 TO 2 ' to search again from the top DO IF Upper(Left(ME.item.Text, i)) = searchstring THEN ' found item RETURN ENDIF IF ME.MoveBelow() THEN BREAK LOOP ME.MoveFirst NEXT Here, the FOR-NEXT is a quick way to execute some code for no more than two times... Again, I could have used a variable to store the result of the test, but I saved it... I think that you use a structure FOR-NEXT that requires to you knowing the amount of iterations to do. But, in this case you know that is likely the number of iterations declared could be unnecesary. So, conceptually, the correct loop would be one that allow control the number of iterations. There isn't a practical problem here. Just a conceptual consideration. This doesn't matter if you understand what you do, like in you case. But I think that's important for who is learning to programming. (I'm sorry, I'm a teacher -and may be some day I have to teach programming-). However, I don't want keep with older patterns of thought. So, will I keep open my mind. Now, image an hypothetical case in that you have to do several conditional actions inside the loop. If you resolves it in that way, the code become hard to understand. Catch the joke: FOR tries = 1 TO 2' to search again from the top DO IF Upper(Left(ME.item.Text, i)) = searchstring THEN ' found item RETURN ENDIF IF ME.MoveBelow() THEN BREAK IF (YOU DONT LIKE) THEN RETURN IF (YOU WANT) THEN RETURN IF (NOT ME ..). THEN BREAK IF (YOU DONT...) THEN BREAK IF (YOU WRITE IN C) THEN RETURN ... LOOP ME.MoveFirst NEXT Ok, I know you wouldn't write something like that. Just I want to serve to show what I mean. I think that clearness and beatiful code is to prefer against speed, but only when speed is not an issue. I agree. In the text-search example speed *is* an issue. Never tried to open a directory with some 3 files in it, and perform a textual search? Ok, I agree. I would do so: PRIVATE FUNCTION ScanTab(IdCaption AS String) AS Byte DIM a AS Byte = 0 WHILE a TabStrip1.Count if TabStrip1[a].Text = IdCaption then return a INC a WEND return -1 END PRIVATE FUNCTION ScanTab(IdCaption AS String) AS Byte DIM a AS Byte for a = 0 to TabStrip1.Count-1 if TabStrip1[a].Text = IdCaption then return a next return -1 END If you have to do tests (like unit tests) and you have routines with multiple exit points, maybe you will have some coverage problems. What do you think? No, the issue is different. Giving any language and any cpu, every operation has a cost. Comparing two
Re: [Gambas-user] static const?
2010/4/14 Doriano Blengino doriano.bleng...@fastwebnet.it: Errata corrige: May be that I am missing something, but... how can you say that it works if it omits to test the last item? Time later, driving to home and still thinking about this routine, I finally recalled what you wanted to say with comprobation. Yes, you are right - your code works. If I would have payed more attention to the routine, I would have noticed. But, stupidly, I concentrated only on the cycle, noting that it was missing a test on the last item. That last item is managed by the last test before exiting. Still I don't like this routine. What happens if TabStrip1.Count=0 (emtpy tabstrip)? Ouch! TabStrip without tabs doesn't fit in my mind, ie Why somebody want a TabStrip without at least one tab? Moreover, by default TabStrip have one tab. (design time and execution time). Listen twice before you speak. This is why we have two ears, but only one mouth. ha! Very funny. I like it. Regards. -- Fabián Flores Vadell www.speedbooksargentina.blogspot.com -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
Re: [Gambas-user] There are errors in the class Key, and in the events KeyPress / KeyRelease?
2010/4/14 Benoît Minisini gam...@users.sourceforge.net: Key.Text is not guaranteed to be set during a KeyRelease. But, refering to the values provided by the key class, is guaranted their availability within the routines that are called from KeyPress? Why it's in that way? Because Qt loses some information needed by the KeyRelease event when some compound keys are used. Ok. Thanks. -- Fabián Flores Vadell www.speedbooksargentina.blogspot.com -- Download Intel#174; Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev ___ Gambas-user mailing list Gambas-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/gambas-user
