Re: Implicit initialization is EXCELLENT
Ian Kelly wrote: On Wed, Jul 6, 2011 at 12:49 AM, Ulrich Eckhardt ulrich.eckha...@dominolaser.com wrote: Mel wrote: In wx, many of the window classes have Create methods, for filling in various attributes in two-step construction. [...] Just guessing, is it legacy, C-with-classes code rather than C++ code perhaps? Haven't looked at wx for a while. Such code typically lacks understanding of exceptions, which are the only way to signal failure from e.g. constructors. No, wx is C++ through and through. No namespaces. No templates but macros. No exceptions. No C++. Sorry, I beg to differ. BTW, they say themselves that they tolerate but not use exceptions, so they actually need two-stage construction if construction can fail, and for exactly the guessed legacy reasons. http://wiki.wxpython.org/TwoStageCreation A C++ object is not a window, it is rather a proxy for managing the window. As such, it can be attached or detached from the underlying window, just like a std::fstream, so in this light it makes sense actually. Thanks for the link! Uli -- Domino Laser GmbH Geschäftsführer: Thorsten Föcking, Amtsgericht Hamburg HR B62 932 -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
On Thu, Jul 7, 2011 at 1:12 AM, Ulrich Eckhardt ulrich.eckha...@dominolaser.com wrote: Just guessing, is it legacy, C-with-classes code rather than C++ code perhaps? Haven't looked at wx for a while. Such code typically lacks understanding of exceptions, which are the only way to signal failure from e.g. constructors. No, wx is C++ through and through. No namespaces. No templates but macros. No exceptions. No C++. Sorry, I beg to differ. BTW, they say themselves that they tolerate but not use exceptions, so they actually need two-stage construction if construction can fail, and for exactly the guessed legacy reasons. Ah, I think I misunderstood your meaning. By C-with-classes I thought you were referring to the practice of OOP in C, and my response was to the effect that building wx requires a C++ compiler, not just a C compiler. -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
rantingrick wrote: On Jul 5, 10:26 am, Steven D'Aprano steve Since you can't do anything without a root window, I don't see the benefit in forcing the user to do so [create one explicitly]. The reason is simple. It's called order. It's called learning from day one how the order of things exists. Widgets are part of windows, not the other way around. Saving a few keystrokes is not acceptable if you jumble the understanding of a new student. To understand and use Tkinter properly you must understand the order of window-widget. When they need to learn about root windows, they will in their own good time. So you would start drivers education class with road construction? Or the history of the internal combustion engine? Who cares about actually *driving* the car. Ahem, you are the one that suggests that in order to drive a car you should first build a road, not Steven! That said, why should I care about the choices and steps I have for creating main windows and the possibilities I get from doing this myself? A basic default main window is enough for me! Further, choice implies I can make wrong choices, too, so forcing someone to make a decision might cause errors. Uli -- Domino Laser GmbH Geschäftsführer: Thorsten Föcking, Amtsgericht Hamburg HR B62 932 -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
Mel wrote: In wx, many of the window classes have Create methods, for filling in various attributes in two-step construction. I'm not sure why, because it works so well to just supply all the details when the class is called and an instance is constructed. Maybe there's some C++ strategy that's being supported there. Just guessing, is it legacy, C-with-classes code rather than C++ code perhaps? Haven't looked at wx for a while. Such code typically lacks understanding of exceptions, which are the only way to signal failure from e.g. constructors. Uli -- Domino Laser GmbH Geschäftsführer: Thorsten Föcking, Amtsgericht Hamburg HR B62 932 -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
Stefaan Himpe wrote: Now, I have an ulterior motive in raising this issue... I can't find the original article I read! My google-fu has failed me (again...). I don't suppose anyone can recognise it and can point me at it? My sarcasm detector warns me not to add a link, although perhaps it's time for recalibration (after all, summer season started) :-) No! I was serious. I've spent *ages* trying to find the link to the article... if you know it, please share. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
No! I was serious. I've spent *ages* trying to find the link to the article... if you know it, please share. Ok - I thought you were referring to some troll's rant with similar title. I'm probably way off, but were you referring to the RAII technique? http://en.wikipedia.org/wiki/Resource_Acquisition_Is_Initialization -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
On Wed, Jul 6, 2011 at 12:49 AM, Ulrich Eckhardt ulrich.eckha...@dominolaser.com wrote: Mel wrote: In wx, many of the window classes have Create methods, for filling in various attributes in two-step construction. I'm not sure why, because it works so well to just supply all the details when the class is called and an instance is constructed. Maybe there's some C++ strategy that's being supported there. Just guessing, is it legacy, C-with-classes code rather than C++ code perhaps? Haven't looked at wx for a while. Such code typically lacks understanding of exceptions, which are the only way to signal failure from e.g. constructors. No, wx is C++ through and through. For the why of it, see: http://wiki.wxpython.org/TwoStageCreation The More Details section is particularly illuminating. -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
Ian Kelly wrote: On Wed, Jul 6, 2011 at 12:49 AM, Ulrich Eckhardt ulrich.eckha...@dominolaser.com wrote: Mel wrote: In wx, many of the window classes have Create methods, for filling in various attributes in two-step construction. I'm not sure why, because it works so well to just supply all the details when the class is called and an instance is constructed. Maybe there's some C++ strategy that's being supported there. Just guessing, is it legacy, C-with-classes code rather than C++ code perhaps? Haven't looked at wx for a while. Such code typically lacks understanding of exceptions, which are the only way to signal failure from e.g. constructors. No, wx is C++ through and through. For the why of it, see: http://wiki.wxpython.org/TwoStageCreation The More Details section is particularly illuminating. Yes, it is. Many thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
Stefaan Himpe wrote: No! I was serious. I've spent *ages* trying to find the link to the article... if you know it, please share. Ok - I thought you were referring to some troll's rant with similar title. I'm probably way off, but were you referring to the RAII technique? http://en.wikipedia.org/wiki/Resource_Acquisition_Is_Initialization Thanks Stefaan, but although it *sounds* like it should be from the title, that's not the idea I'm talking about. Despite the name, RAII is more about destructor/finalizer methods than initialisation. The blog post I'm looking for is not about finalizers, but about API design: don't make the caller give an explicit second activation call if you don't need to. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Implicit initialization is EXCELLENT
This is not strictly Python, although it is peripherally relevant. Some month or three ago, I read an article or blog post about API design, specifically the wrong-headedness of insisting that callers manually initialise instances using a separate step after creation. The argument goes, if your API looks something like this: instance = Spaminator(extra_truffles=False) instance.activate() instance.nom_nom_nom() = prints yummy spam, the food of the Gods!!! chances are that you are doing it wrong and your users will hate you. Why force the user to manually flip the switch (so to speak)? It's not like they can possibly avoid it: another_instance = Spaminator(with_extra_cheese=True) another_instance.nom_nom_nom() = raises InactiveInstanceError(you must activate the instance first) What? No! Just activate yourself! Exceptions to this rule are if the Spaminator has side-effects (e.g. files, in which case the user may want finer control in when they are opened and closed), or if there are meaningful operations you can perform on an inactive Spaminator. Python generally follows this design. Apart from files, I can't easily think off the top of my head of any types that require a separate open/start/activate call before they are usable. It's also relevant to tkinter, which will implicitly create a root window for you when needed. Since you can't do anything without a root window, I don't see the benefit in forcing the user to do so. When they need to learn about root windows, they will in their own good time. Now, I have an ulterior motive in raising this issue... I can't find the original article I read! My google-fu has failed me (again...). I don't suppose anyone can recognise it and can point me at it? -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
Hi! +1 @-salutations -- Michel Claveau -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
Steven D'Aprano wrote: [ ... ] Python generally follows this design. Apart from files, I can't easily think off the top of my head of any types that require a separate open/start/activate call before they are usable. It's also relevant to tkinter, which will implicitly create a root window for you when needed. Since you can't do anything without a root window, I don't see the benefit in forcing the user to do so. When they need to learn about root windows, they will in their own good time. In wx, many of the window classes have Create methods, for filling in various attributes in two-step construction. I'm not sure why, because it works so well to just supply all the details when the class is called and an instance is constructed. Maybe there's some C++ strategy that's being supported there. Mel. -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
Hello, I agree with the contents of this post. I see a similar problem with API's requiring to initialize all kinds of data using setters/properties instead of receiving it in the initializer (or constructor). Python generally follows this design. Apart from files, I can't easily think off the top of my head of any types that require a separate open/start/activate call before they are usable. database connections, network connections, spawning expensive processes/threads, things that benefit from lazy evaluation... Now, I have an ulterior motive in raising this issue... I can't find the original article I read! My google-fu has failed me (again...). I don't suppose anyone can recognise it and can point me at it? My sarcasm detector warns me not to add a link, although perhaps it's time for recalibration (after all, summer season started) :-) Best regards, Stefaan. -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
In BEJQp.25947$Sr.7633@newsfe12.ams2 Stefaan Himpe stefaan.hi...@gmail.com writes: Now, I have an ulterior motive in raising this issue... I can't find the original article I read! My google-fu has failed me (again...). I don't suppose anyone can recognise it and can point me at it? My sarcasm detector warns me not to add a link, although perhaps it's time for recalibration (after all, summer season started) :-) He's not asking for a link to the Implicit initialization is EVIL thread; he's asking for a link to the original article he read elsewhere which praised the bendfists of implicit initialization. -- John Gordon A is for Amy, who fell down the stairs gor...@panix.com B is for Basil, assaulted by bears -- Edward Gorey, The Gashlycrumb Tinies -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
In iuvu5p$g1n$1...@reader1.panix.com John Gordon gor...@panix.com writes: which praised the bendfists of implicit initialization. Wow, that's quite a typo! I meant benefits, of course. -- John Gordon A is for Amy, who fell down the stairs gor...@panix.com B is for Basil, assaulted by bears -- Edward Gorey, The Gashlycrumb Tinies -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
On Jul 5, 10:26 am, Steven D'Aprano steve +comp.lang.pyt...@pearwood.info wrote: This is not strictly Python, although it is peripherally relevant. Some month or three ago, I read an article or blog post about API design, specifically the wrong-headedness of insisting that callers manually initialise instances using a separate step after creation. The argument goes, if your API looks something like this: instance = Spaminator(extra_truffles=False) instance.activate() instance.nom_nom_nom() = prints yummy spam, the food of the Gods!!! chances are that you are doing it wrong and your users will hate you. Why force the user to manually flip the switch (so to speak)? It's not like they can possibly avoid it: I completely agree! Exceptions to this rule are if the Spaminator has side-effects (e.g. files, in which case the user may want finer control in when they are opened and closed), or if there are meaningful operations you can perform on an inactive Spaminator. Agreed again! It's also relevant to tkinter, which will implicitly create a root window for you when needed. WRONG. Oh wait, of course, you are correct! YES! Maybe we should have library modules import only when needed! i mean, who needs those pesky import statements anyways! Sure it will slow down run time BUT WHO CARES! My gawd, you just opened my mind to so many possibilities! Why stop at library modules, if it is not there just download the source at run time! Guido really dropped the ball on this one folks. Since you can't do anything without a root window, I don't see the benefit in forcing the user to do so. The reason is simple. It's called order. It's called learning from day one how the order of things exists. Widgets are part of windows, not the other way around. Saving a few keystrokes is not acceptable if you jumble the understanding of a new student. To understand and use Tkinter properly you must understand the order of window-widget. When they need to learn about root windows, they will in their own good time. So you would start drivers education class with road construction? Or the history of the internal combustion engine? Who cares about actually *driving* the car. -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
On Wed, Jul 6, 2011 at 11:53 AM, rantingrick rantingr...@gmail.com wrote: So you would start drivers education class with road construction? Or the history of the internal combustion engine? Who cares about actually *driving* the car. I believe that starting driver ed with some basics of how an internal combustion engine works would be a Good Thing. If you're going to be in control of a ton of steel that's capable of moving at a hundred kays, you ought to know at least a bit about what provides the kinetic energy. There's a difference between comprehension and jumping through hoops. In your driver ed example, I don't believe that the accelerator pedal should be replaced with a flexible fuel-line that the driver squeezes to control flow to the engine; but on the other hand, I don't think the brake pedal should be replaced by a single button saying stop car either. Arrogance is a normal part of designing programming languages (see Larry Wall's comments regarding Perl, for instance). But arrogance to the extent of forcing your views on programmers is generally resented, and with good reason. If you force too much on people, they'll go elsewhere. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
On Jul 5, 9:44 pm, Chris Angelico ros...@gmail.com wrote: On Wed, Jul 6, 2011 at 11:53 AM, rantingrick rantingr...@gmail.com wrote: So you would start drivers education class with road construction? Or the history of the internal combustion engine? Who cares about actually *driving* the car. I believe that starting driver ed with some basics of how an internal combustion engine works would be a Good Thing. If you're going to be in control of a ton of steel that's capable of moving at a hundred kays, you ought to know at least a bit about what provides the kinetic energy. How about kinetic energy itself? If you know *what* produces power to induce kinetic energy into the vehicle but not *how* the laws of physics govern kinetic energy; what damn good is that going to do for you? How about some basics of safe/defensive driving? How about considering the good of the many instead of the you? There's a difference between comprehension and jumping through hoops. Likewise for priorities and acting aloof. If you force too much on people, they'll go elsewhere. Why all this running away with tail between legs? Do these these people have extremely small eggs? I wish they would stand firm and put up a fight instead they're just cowards spewing more endless tripe. -- http://mail.python.org/mailman/listinfo/python-list
Re: Implicit initialization is EXCELLENT
On Wed, Jul 6, 2011 at 1:45 PM, rantingrick rantingr...@gmail.com wrote: If you force too much on people, they'll go elsewhere. Why all this running away with tail between legs? Do these these people have extremely small eggs? I wish they would stand firm and put up a fight instead they're just cowards spewing more endless tripe. Standing up and fighting takes effort. It's a lot easier - and a lot more time-efficient - to ignore idiots and trolls and just get some work done. I think I'll do that, right now. Chris Angelico -- http://mail.python.org/mailman/listinfo/python-list
