On Thu, 18 Sep 2008, Joshua Choi wrote:
> @Mr. Sasse: > > > "only"! I didn't know you could do that at all. In ruby a lowercase > > name is just a method, but it may have nothing to do with any particular > > class. > > Actually, what you're referring to here is tangent to the issue I'm > talking about, but I'll explain it. > > This is a Shoes-specific thing: I found out about it in Mr. Why's post > about custom widgets > (http://hackety.org/2008/06/12/martinDemellosGooeyChallenge.html). > When Shoes can't find a method, it apparently looks for a class with Oh, right. OK. > the same name (case insensitive); if it finds one, it initializes it > with the method's arguments. For instance. Mr. Why created a > BorderButton class, and he initialized an BorderButton object with the > method borderbutton. (Mr. Why probably did this to be consistent with > methods like button() and para(), which initialize classes like Button > and Para.) I never thought they were done by method_missing. Very nice. > > Now, probably for speed purposes, he's apparently limited it to Widget > subclasses only...but I may be mistaken. > > > > > I've looked at that pretty carefully and they look the same to me. > > > > The difference is in the OKButton class's superclass. One is Button > (doesn't work now); the other is Widget. I correspondingly called > either super() or button() in the class's initialize() method. Now you know why I hate proofreading! I see that now. :-) > > > How exactly did you do that? If your program was running, then the > > initial shoes dialogue goes away, so you just have the interface you > > wrote. > > I'm not sure what the second sentence means, but that's probably my > ignorance. :) I think I can guess at your question (forgive me if you > already know the next part). In Mac OS X, Shoes runs as a single > Application, which opens Ruby and Shy files. A single running OS X > application hosts many Shoes programs. However, it seems like as long > as I don't actually quit from the Shoes application, programs' classes > or something are saved—I'm guessing this because quitting the Shoes > application and relaunching it, then opening my own program in it, > gets rid of the superclass clash error and thus seems to "reset" > whatever it saved. Ok. I've not tested running multiple shoes apps on Windows to be sure it's the same. Yes, then it is probably the we-can-extend-classes bit of ruby that is doing this. > > > Do you have the exact text of the error? > > Here it is (I'll have to type this out—I wish it were possible to > select text in a Shoes program. :( )... I've asked for that, too. The selection would get picked up by Microsoft Narrator give speech access to the specific bits one would wish. I don't know enough cairo to contribute, so I'll be patient. > > Error in /Applications/Shoes/..blah, blah.../lib/shoes.rb line 359 > > superclass mismatch for class OKButton Ah, I've never seen that in ruby but I think it works like this Classes begin with Capitals, so they are constants. The fact you can change what is inside them doesn't matter. So it looks for the constant and matches it but the superclass of the original doesn't match. Thus the original definition is still in memory. Can I prove that? irb(main):001:0> irb(main):002:0* class HP; end => nil irb(main):003:0> class Compaq; end => nil irb(main):004:0> class MyPC < Compaq ; end => nil irb(main):005:0> # HP by compaq irb(main):006:0* irb(main):007:0* class MyPC < HP ; def id; puts self.class; end ; end TypeError: superclass mismatch for class MyPC from (irb):7 irb(main):008:0> irb(main):009:0* > > I fear that I'm poorly explaining this problem. Here's the deal: in > Mac OS X, Shoes runs as a single application. I keep it open all the > time when I program so that when I run my program, I can just switch > to it, instead of relaunching it and bringing up the console window > every time. can't you put a #!shoes line in your shoes programs as we can in Windows? I don't even bother with the full path to shoes for this, and as new build get new subdirs.... I suppose I could point at the shoes.bat that always lives at the top. Anyway, all the .rb files get marked as being ruby, but ruby honours the #! line of scripts, so it can even run Perl scripts correctly! That way you can just click on the icon to run it. > > However, when I edited a program by changing a class's superclass, and > then ran it in Shoes, Shoes could not compile it. It raised the error > you see above. This made me suspect that Shoes keeps some sort of data > as long as it's open to speed up future programs. However, it raises > the possibility of very surprising behavior to happen in the future, > like this error today. And if it shares the memory between programs then one might have weird effects. class Tank attr_accessor :fish, :plants, :shells def needs_cleaning? .... end end meanwhile... class Tank attr_accesor :shells, :soldiers def aim(target) .... end end You can supply your own fish puns at this point. > > > If a ruby program reads files with the same classes in, the classes > > get extended. Yes, this can lead to problems. > > Yes, and if this can lead to problems, then documentation is needed on > how this persistence works in Shoes. I appeal to Mr. Why: could you > explain why this behavior is happening? > > Thank you everyone for replying, and sincerely, > Joshua Choi > [Postscript trimmed.] Hugh
