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Re: [wxlua-users] Event handling function inside a module
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From: Milind G. <mil...@gm...> - 2012-02-16 22:18:04
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Thanks, Milind On Thu, Feb 16, 2012 at 1:53 PM, Mike Richards <mri...@gm...> wrote: > Milind, > You could also accomplish the same with a little less typing if you want: > > module(...) > local _M = _M -- save the module table > > then in your event handler function it's just setfenv(1, _M) > > Mike > > On 2/16/2012 4:42 PM, Milind Gupta wrote: > > Hi Mike, > I agree a good practice is to declare things local, only for things > we want to access from outside unrestricted its easier not to declare them > local. So anyway what I ended up doing is having the first statement in my > event handler function as setfenv(1,package.loaded[modname]) where modname > is the name of the module passed by lua to the module. Since require loads > the module function there so it just picks it up from there. > > Thanks, > Milind > > On Thu, Feb 16, 2012 at 12:06 PM, Mike Richards <mri...@gm...>wrote: > >> John and Milind, >> >> function test() is declared in the current scope, and globally as >> filterform.test >> >> After fiddling around for a bit, it looks like wx.wxEvtHandler:Connect >> saves upvalues, but not the current function environment (scope), which was >> set in the call to module(...) >> When the event function is called, the function environment is reset to >> the global scope, so if you want to reference things you declared in the >> module scope in the event callback, you have a couple of options: >> 1. Declare everything as local, which to me is just good practice. >> 2. Use a fully qualified name (e.g. filterform.test()) >> 3. Wrap all your calls to wx.wxEvtHandler:Connect like this: >> >> function Connect(evthandler, id, func) >> local environment = getfenv(1) >> evthandler:Connect(id, >> function(event) >> setfenv(1, environment) >> func(event) >> end >> ) >> end >> >> [...] >> >> local button = wx.Button([...]) >> Connect(button, wx.wxEVT_COMMAND_BUTTON_CLICKED, function(event) end) >> >> John -- It seems like wx.wxEvtHandler:Connect should do this anyways . . >> . that is, save the current function environment, and then apply it before >> calling the callback. >> >> Mike >> >> >> On 2/16/2012 3:14 AM, Milind Gupta wrote: >> >> Hello John, >> Sorry for the carelessness. Here is a full set with >> minimal.lua which is the main file to run and the module function is called >> by the Help->About call back. That is true making test a local function >> makes it work although I am not totally clear why but if you press the >> other button 'Clear Task' it will give an error complaining about filter >> which again is not declared local. Actually declaring local anything in a >> module only makes it private. Whether it is declared local or not it always >> resides in the module environment. So even if test or filter are not >> declared local they should be identified in the module environment. Here is >> the Programming in Lua Modules and Packages chapter that clarifies it: >> >> http://www.inf.puc-rio.br/~roberto/pil2/chapter15.pdf >> >> At least that is how I understood it. So I think it should work without >> being declared local. In your previous email you said that the environment >> is saved as an upvalue with the execution of Connect. I am not sure how >> that would be done since the module itself does not know what environment >> to Global it will be in. Like if you see in minimal I placed it in the >> environment newPackage and all my functions tables declared in the module >> i.e. test, filter, etc. are in the table newPackage in the global >> environment but the module code has no way of knowing that. >> One last point is that unless its an event callback function normal >> functions in the module run just fine whether test is local or not. As an >> example I just added the test() call as the first line in >> filterFormActivate which is a non event function so when the Help-> About >> callback calls filterFormActivate, test() just runs fine even though it is >> not local but now if you press the Select Task button it will say it could >> not find test(). >> >> >> Milind >> >> >> On Wed, Feb 15, 2012 at 3:14 AM, Milind Gupta <milind.gupta@...><milind.gupta@...>wrote: >> > Hello John, >> > >> > thanks for the reply. Here is an example code that does not >> work >> >> Please try to provide enough code to make it run out of the box... I >> had to add back GUI.initFrameH and rem out the usage of MainSizer to >> make it even possible to run without error. >> >> > (Pasted below and attached the file as well). A function from the >> main wxlua >> > application calls filterFormActivate which sets up a simple frame with 2 >> > buttons and one static text and associates the button click to >> SelTaskPress. >> >> I made the help menu callback function of the minimal.wx.lua sample >> call filterform.filterFormActivate(frame). >> >> > But when the button is clicked the test() statement gives an error. >> If that >> > is removed then it cannot recognize the frame varaiable in the >> > wx.wxFrame(frame line after test(). >> >> Please always include these errors in the future to help diagnose the >> problem. >> >> In order to solve your problem I made test() a local function so that >> it will be an upvalue of the Connect() function that calls it. Note >> that the 'frame' that is used in the SelTaskPress() function is the >> frame from the minimal.wx.lua and not the frame from >> filterFormActivate(). >> >> To be honest, I have not done too much with modules and require in Lua >> since I'm not sure I fully understand its behavior. >> >> I just came across this which clears some things up for me. Note the >> sentence "This means that any global functions are not visible by >> default, which is why we had to create a local alias to print." This >> is probably also why making test() local above fixed it. See also >> package.seeall which might be useful to you. >> http://www.luafaq.org/#T1.37 >> >> Hope this helps, >> John >> >> >> >> ------------------------------------------------------------------------------ >> Virtualization & Cloud Management Using Capacity Planning >> Cloud computing makes use of virtualization - but cloud computing >> also focuses on allowing computing to be delivered as a service.http://www.accelacomm.com/jaw/sfnl/114/51521223/ >> >> >> >> _______________________________________________ >> wxlua-users mailing lis...@li...https://lists.sourceforge.net/lists/listinfo/wxlua-users >> >> >> >> ------------------------------------------------------------------------------ >> Virtualization & Cloud Management Using Capacity Planning >> Cloud computing makes use of virtualization - but cloud computing >> also focuses on allowing computing to be delivered as a service. >> http://www.accelacomm.com/jaw/sfnl/114/51521223/ >> _______________________________________________ >> wxlua-users mailing list >> wxl...@li... >> https://lists.sourceforge.net/lists/listinfo/wxlua-users >> >> > > > ------------------------------------------------------------------------------ > Virtualization & Cloud Management Using Capacity Planning > Cloud computing makes use of virtualization - but cloud computing > also focuses on allowing computing to be delivered as a service.http://www.accelacomm.com/jaw/sfnl/114/51521223/ > > > > _______________________________________________ > wxlua-users mailing lis...@li...https://lists.sourceforge.net/lists/listinfo/wxlua-users > > > > ------------------------------------------------------------------------------ > Virtualization & Cloud Management Using Capacity Planning > Cloud computing makes use of virtualization - but cloud computing > also focuses on allowing computing to be delivered as a service. > http://www.accelacomm.com/jaw/sfnl/114/51521223/ > _______________________________________________ > wxlua-users mailing list > wxl...@li... > https://lists.sourceforge.net/lists/listinfo/wxlua-users > > |