Re: [GNC-dev] Python: About Wrapping SWIG Objects (GncNumeric)
Am 2018-08-06 16:14, schrieb John Ralls: On Aug 6, 2018, at 5:19 AM, c.holterm...@gmx.de wrote: Am 2018-08-06 11:35, schrieb Geert Janssens: Op maandag 6 augustus 2018 05:32:27 CEST schreef John Ralls: > On Aug 5, 2018, at 5:17 PM, c.holterm...@gmx.de wrote: > > Hello, > > after some time I get back to the gnucash python bindings. > > I worked on a str method for GncNumeric. It's in the example_script > dir > (https://github.com/Gnucash/gnucash/blob/maint/bindings/python/example_sc > ripts/str_methods.py) I changed it to python3. I read at the beginning of this file you chose to implement it as an example script which - if found useful - could be added to gnucash_core. You have my blessing to include it in gnucash_core :) > Well I found it interesting to think these things through. Maybe someone > can tell me about the mysterious "later on" in the cited comment. At this > point I find it useful to have a way from the instance to the wrapping > object through some kind of link as I suggested in the patch to > function_class. Christoph, The person who wrote the first two lines of that, Mark Jenkins, was the original source of the Python bindings. He was never a regular dev, he just got 16 patches committed between 2007 and 2012, 10 of which touched the python bindings. Your history with them is almost as long as his--in fact you have *12* commits--and pretty much no one else has done anything serious with them. Hopefully Mark is still around on the list to clarify. In other words, if anyone knows, it’s you! True :) Just to add some more confusion, there’s now a C++ class GncNumeric that handles the actual implementation of many of the gnc_numeric.* functions. I believe that SWIG can’t see it, only the C wrapper functions are exposed to SWIG. It would be a very useful experiment to wrap the C++ GncNumeric class directly rather than it's c wrapper gnc_numeric_xxx. Python doesn't need the c compatibility layer it represents. Geert Geert, unfortunately your mail went to my spam folder for whatever reason. Trying to do C++ bindings for python sounds very interesting. I'd like to try that when I find the time for a simple example type. I don't know if GncNumeric would be a good candidate. I'll have a look at it. Thanks for the blessing :-) Python has its own rational numbers so the only thing the Python bindings need is a way to convert to-and-from that to GncNumeric for communicating with the rest of the GnuCash API. I suggest QofSession as the first C++ class to play with SWIGing. It’s fairly simple and using it is the first step in using the bindings. Regards, John Ralls Hello, I've created an experimental branch in my fork of gnucash to create swig python bindings for c++ files. As suggested I started with QofSessionImpl for which I have created an example file to create a file and an account. I also included GncNumeric. There's no example for that yet. It's very raw. I disabled some errors. It's more of a proof of concept but it's a step on the way. https://github.com/c-holtermann/gnucash/tree/ch-python regards, Christoph Holtermann ___ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
Re: [GNC-dev] Python: About Wrapping SWIG Objects (GncNumeric)
Christoph Holtermann wrote > I'm willing to now and then do something for the python bindings. I > don't feel like an expert. But surely I'd like to talk and think things > through > about them. Maybe someone is interested. I saw that there were some people > asking questions about the bindings on this list. Maybe they don't commit > but > still work with the bindings. So my question remains and maybe someone has > an > idea. Christoph, I, for example, am quite interested in accessing GnuCash via Python. So, on first sight, Python bindings seem an interesting option. In practice, though, I did not find much motivation to spend time on it, unfortunately. The main reason for that is that I need my (Python) code to run on Windows, Linux, and Android. And to run equally well. Since the bindings are available only on Linux, that's a very limiting factor. So I've limited my work to only reading the GnuCash data. Additional functionality is dispersed across various small projects that keep extra information in their own databases (i.e. Asset Allocation). This works well on Android and I can get my Portfolio Value report or Security Analysis by running a Python script on my phone (sounds weird, I know). To run on all platforms I'm using Sebastien's Piecash library. Additional step would be to add some sort of (native) GUI on all the platforms. I've already looked into that a bit, but nothing tickles my fancy yet. Having the ability to write data to GnuCash would be fantastic. However, I don't think it's going to happen on multiple platforms any time soon. Naturally, it is possible to write to GnuCash database but that is not exactly the same as using GnuCash's business logic. One thing I would like to improve on next is the process of getting the transactions from the mobile app (MoneyManagerEx for Android) into GnuCash. Python bindings would be perfect for that, to avoid lengthy process of .qif import. I could adapt the Android app to provide GnuCash-specific export file, for example. But if this would work only on Linux, it would be a very small return on the investment of time and effort. -- Sent from: http://gnucash.1415818.n4.nabble.com/GnuCash-Dev-f1435356.html ___ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
Re: [GNC-dev] Python: About Wrapping SWIG Objects (GncNumeric)
Am 2018-08-06 16:14, schrieb John Ralls: On Aug 6, 2018, at 5:19 AM, c.holterm...@gmx.de wrote: Am 2018-08-06 11:35, schrieb Geert Janssens: Op maandag 6 augustus 2018 05:32:27 CEST schreef John Ralls: > On Aug 5, 2018, at 5:17 PM, c.holterm...@gmx.de wrote: > > Hello, > > after some time I get back to the gnucash python bindings. > > I worked on a str method for GncNumeric. It's in the example_script > dir > (https://github.com/Gnucash/gnucash/blob/maint/bindings/python/example_sc > ripts/str_methods.py) I changed it to python3. I read at the beginning of this file you chose to implement it as an example script which - if found useful - could be added to gnucash_core. You have my blessing to include it in gnucash_core :) > Well I found it interesting to think these things through. Maybe someone > can tell me about the mysterious "later on" in the cited comment. At this > point I find it useful to have a way from the instance to the wrapping > object through some kind of link as I suggested in the patch to > function_class. Christoph, The person who wrote the first two lines of that, Mark Jenkins, was the original source of the Python bindings. He was never a regular dev, he just got 16 patches committed between 2007 and 2012, 10 of which touched the python bindings. Your history with them is almost as long as his--in fact you have *12* commits--and pretty much no one else has done anything serious with them. Hopefully Mark is still around on the list to clarify. In other words, if anyone knows, it’s you! True :) Just to add some more confusion, there’s now a C++ class GncNumeric that handles the actual implementation of many of the gnc_numeric.* functions. I believe that SWIG can’t see it, only the C wrapper functions are exposed to SWIG. It would be a very useful experiment to wrap the C++ GncNumeric class directly rather than it's c wrapper gnc_numeric_xxx. Python doesn't need the c compatibility layer it represents. Geert Geert, unfortunately your mail went to my spam folder for whatever reason. Trying to do C++ bindings for python sounds very interesting. I'd like to try that when I find the time for a simple example type. I don't know if GncNumeric would be a good candidate. I'll have a look at it. Thanks for the blessing :-) Python has its own rational numbers so the only thing the Python bindings need is a way to convert to-and-from that to GncNumeric for communicating with the rest of the GnuCash API. I suggest QofSession as the first C++ class to play with SWIGing. It’s fairly simple and using it is the first step in using the bindings. Regards, John Ralls John, Thanks for the suggestion. I'll also think about what you said about the numerics. regards, Christoph Holtermann ___ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
Re: [GNC-dev] Python: About Wrapping SWIG Objects (GncNumeric)
> On Aug 6, 2018, at 5:19 AM, c.holterm...@gmx.de wrote: > > Am 2018-08-06 11:35, schrieb Geert Janssens: >> Op maandag 6 augustus 2018 05:32:27 CEST schreef John Ralls: >>> > On Aug 5, 2018, at 5:17 PM, c.holterm...@gmx.de wrote: >>> > >>> > Hello, >>> > >>> > after some time I get back to the gnucash python bindings. >>> > >>> > I worked on a str method for GncNumeric. It's in the example_script >>> > dir >>> > (https://github.com/Gnucash/gnucash/blob/maint/bindings/python/example_sc >>> > ripts/str_methods.py) I changed it to python3. >> I read at the beginning of this file you chose to implement it as an example >> script which - if found useful - could be added to gnucash_core. >> You have my blessing to include it in gnucash_core :) >>> > Well I found it interesting to think these things through. Maybe someone >>> > can tell me about the mysterious "later on" in the cited comment. At this >>> > point I find it useful to have a way from the instance to the wrapping >>> > object through some kind of link as I suggested in the patch to >>> > function_class. >>> Christoph, >>> The person who wrote the first two lines of that, Mark Jenkins, was the >>> original source of the Python bindings. He was never a regular dev, he just >>> got 16 patches committed between 2007 and 2012, 10 of which touched the >>> python bindings. Your history with them is almost as long as his--in fact >>> you have *12* commits--and pretty much no one else has done anything >>> serious with them. >> Hopefully Mark is still around on the list to clarify. >>> In other words, if anyone knows, it’s you! >> True :) >>> Just to add some more confusion, there’s now a C++ class GncNumeric that >>> handles the actual implementation of many of the gnc_numeric.* functions. I >>> believe that SWIG can’t see it, only the C wrapper functions are exposed to >>> SWIG. >> It would be a very useful experiment to wrap the C++ GncNumeric class >> directly >> rather than it's c wrapper gnc_numeric_xxx. Python doesn't need the c >> compatibility layer it represents. >> Geert > > Geert, > > unfortunately your mail went to my spam folder for whatever reason. Trying to > do C++ bindings for python sounds very interesting. I'd like to try that when > I find the time for a simple example type. I don't know if GncNumeric would > be a good candidate. I'll have a look at it. Thanks for the blessing :-) Python has its own rational numbers so the only thing the Python bindings need is a way to convert to-and-from that to GncNumeric for communicating with the rest of the GnuCash API. I suggest QofSession as the first C++ class to play with SWIGing. It’s fairly simple and using it is the first step in using the bindings. Regards, John Ralls ___ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
Re: [GNC-dev] Python: About Wrapping SWIG Objects (GncNumeric)
Am 2018-08-06 11:35, schrieb Geert Janssens: Op maandag 6 augustus 2018 05:32:27 CEST schreef John Ralls: > On Aug 5, 2018, at 5:17 PM, c.holterm...@gmx.de wrote: > > Hello, > > after some time I get back to the gnucash python bindings. > > I worked on a str method for GncNumeric. It's in the example_script > dir > (https://github.com/Gnucash/gnucash/blob/maint/bindings/python/example_sc > ripts/str_methods.py) I changed it to python3. I read at the beginning of this file you chose to implement it as an example script which - if found useful - could be added to gnucash_core. You have my blessing to include it in gnucash_core :) > Well I found it interesting to think these things through. Maybe someone > can tell me about the mysterious "later on" in the cited comment. At this > point I find it useful to have a way from the instance to the wrapping > object through some kind of link as I suggested in the patch to > function_class. Christoph, The person who wrote the first two lines of that, Mark Jenkins, was the original source of the Python bindings. He was never a regular dev, he just got 16 patches committed between 2007 and 2012, 10 of which touched the python bindings. Your history with them is almost as long as his--in fact you have *12* commits--and pretty much no one else has done anything serious with them. Hopefully Mark is still around on the list to clarify. In other words, if anyone knows, it’s you! True :) Just to add some more confusion, there’s now a C++ class GncNumeric that handles the actual implementation of many of the gnc_numeric.* functions. I believe that SWIG can’t see it, only the C wrapper functions are exposed to SWIG. It would be a very useful experiment to wrap the C++ GncNumeric class directly rather than it's c wrapper gnc_numeric_xxx. Python doesn't need the c compatibility layer it represents. Geert Geert, unfortunately your mail went to my spam folder for whatever reason. Trying to do C++ bindings for python sounds very interesting. I'd like to try that when I find the time for a simple example type. I don't know if GncNumeric would be a good candidate. I'll have a look at it. Thanks for the blessing :-) have a nice day ! Christoph ___ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
Re: [GNC-dev] Python: About Wrapping SWIG Objects (GncNumeric)
Op maandag 6 augustus 2018 11:35:43 CEST schreef c.holterm...@gmx.de: > Then you speak of c++ GncNumeric. As I understand you are moving the > source > from c to c++. So the python bindings need to reflect that. That sounds > like > another piece of work. Is there imminent need for change there ? Chances > of > breaking changes ? We're indeed converting the internals of gnucash (that part we refer to as "libgnucash" among developers) to c++. As long as parts of gnucash as a whole still depend on the c interface that will continue to exist as a wrapper around the c++ code. So the C interface will probably still be around for a couple of years. So there is still quite some time available to port the python bindings. I suggested this as an interesting project in my previous mail. Thinking about this some more it probably only makes sense when all of the objects that are being wrapped are converted to C++. I guess the wrapper would otherwise have to wrap both the C and the C++ interface to provide full functionality, which sounds a bit awkward. A first experiment to get an idea of what to expect on the other hand may still be useful. Regards, Geert ___ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
Re: [GNC-dev] Python: About Wrapping SWIG Objects (GncNumeric)
Am 2018-08-06 05:32, schrieb John Ralls: On Aug 5, 2018, at 5:17 PM, c.holterm...@gmx.de wrote: Hello, after some time I get back to the gnucash python bindings. I worked on a str method for GncNumeric. It's in the example_script dir (https://github.com/Gnucash/gnucash/blob/maint/bindings/python/example_scripts/str_methods.py) I changed it to python3. Then I began to wonder about the relationshipp of the SwigObject and the wrapping object. In this case it's something like '_gnc_numeric *' at 0x7f11908da840> > and When I have the GncNumeric object I can access the SwigObject through its instance property. The other way round seems not as simple. My method __gncnumeric__str__ overwrites the __str__ method using add_method. In this method self points to the swig object. I cannot use the methods of GncNumeric as it is the layer of the wrapping object. To access these methods I used to instantiate a GncNumeric(instance=self) as a temporary self. But that seems not right as this probably already exists. I wondered if I could know about the wrapping object when I had the instance only. I did not find a way. I stumbled over an interesting comment in https://github.com/Gnucash/gnucash/blob/69fef8277fde56e7d2df700b21c63c19c115852a/bindings/python/function_class.py#L50 # why reimpliment __new__? Because later on we're going to # use new to avoid creating new instances when existing instances # already exist with the same __instance value, or equivalent __instance # values, where this is desirable... I did not find "later on". But if that works I can safely do GncNumeric(instance=self) as it would reuse the existing GncNumeric object. But nevertheless I wondered if we could put a link to the GncNumeric in the Swig Level. I tried it: https://github.com/c-holtermann/gnucash/commit/a6c2adf7d29c4367728a4fa920307ee595eefa5a (link to my fork) Interstingly some Swig objects can be added to and some others not. GncNumeric works while QofSession doesn't. So I made it a try block for now. Having done that I can get to the GncNumeric (sort of higher self) from the Swig object: https://github.com/c-holtermann/gnucash/commit/2f35b550709ad4131aca0e7309f6bb4b0f984b84 Well I found it interesting to think these things through. Maybe someone can tell me about the mysterious "later on" in the cited comment. At this point I find it useful to have a way from the instance to the wrapping object through some kind of link as I suggested in the patch to function_class. Christoph, The person who wrote the first two lines of that, Mark Jenkins, was the original source of the Python bindings. He was never a regular dev, he just got 16 patches committed between 2007 and 2012, 10 of which touched the python bindings. Your history with them is almost as long as his--in fact you have *12* commits--and pretty much no one else has done anything serious with them. In other words, if anyone knows, it’s you! Just to add some more confusion, there’s now a C++ class GncNumeric that handles the actual implementation of many of the gnc_numeric.* functions. I believe that SWIG can’t see it, only the C wrapper functions are exposed to SWIG. Regards, John Ralls John, thank you for the insights and the friendly words. I like the python bindings for gnucash and use them to feed my bank data to gnucash using a webscraping script that fetches a CSV for me which I can then import using the bindings. This has worked quite well for me for years. At some point in time gnucash wouldn't build due to some segmentation error. The system was working but I only now came back to compile gnucash again when I made a big system update. I'm willing to now and then do something for the python bindings. I don't feel like an expert. But surely I'd like to talk and think things through about them. Maybe someone is interested. I saw that there were some people asking questions about the bindings on this list. Maybe they don't commit but still work with the bindings. So my question remains and maybe someone has an idea. I will continue to think about it anyway (depending on the time I can spare on this project :-). I thought I will look through the python bindings and see if all files are compatible with python3. Thanks to you developers who made that step for the bindings ! I suppose some of the example scripts are not yet converted. The information in the wiki should reflect the step to python3. I'll try to have a look at that. Then you speak of c++ GncNumeric. As I understand you are moving the source from c to c++. So the python bindings need to reflect that. That sounds like another piece of work. Is there imminent need for change there ? Chances of breaking changes ? regards, Christoph Holtermann ___ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
Re: [GNC-dev] Python: About Wrapping SWIG Objects (GncNumeric)
Op maandag 6 augustus 2018 05:32:27 CEST schreef John Ralls: > > On Aug 5, 2018, at 5:17 PM, c.holterm...@gmx.de wrote: > > > > Hello, > > > > after some time I get back to the gnucash python bindings. > > > > I worked on a str method for GncNumeric. It's in the example_script > > dir > > (https://github.com/Gnucash/gnucash/blob/maint/bindings/python/example_sc > > ripts/str_methods.py) I changed it to python3. I read at the beginning of this file you chose to implement it as an example script which - if found useful - could be added to gnucash_core. You have my blessing to include it in gnucash_core :) > > Well I found it interesting to think these things through. Maybe someone > > can tell me about the mysterious "later on" in the cited comment. At this > > point I find it useful to have a way from the instance to the wrapping > > object through some kind of link as I suggested in the patch to > > function_class. > > Christoph, > > The person who wrote the first two lines of that, Mark Jenkins, was the > original source of the Python bindings. He was never a regular dev, he just > got 16 patches committed between 2007 and 2012, 10 of which touched the > python bindings. Your history with them is almost as long as his--in fact > you have *12* commits--and pretty much no one else has done anything > serious with them. > Hopefully Mark is still around on the list to clarify. > In other words, if anyone knows, it’s you! True :) > > Just to add some more confusion, there’s now a C++ class GncNumeric that > handles the actual implementation of many of the gnc_numeric.* functions. I > believe that SWIG can’t see it, only the C wrapper functions are exposed to > SWIG. > It would be a very useful experiment to wrap the C++ GncNumeric class directly rather than it's c wrapper gnc_numeric_xxx. Python doesn't need the c compatibility layer it represents. Geert ___ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
Re: [GNC-dev] Python: About Wrapping SWIG Objects (GncNumeric)
> On Aug 5, 2018, at 5:17 PM, c.holterm...@gmx.de wrote: > > Hello, > > after some time I get back to the gnucash python bindings. > > I worked on a str method for GncNumeric. It's in the example_script > dir > (https://github.com/Gnucash/gnucash/blob/maint/bindings/python/example_scripts/str_methods.py) > I changed it to python3. Then I began to wonder about the relationshipp of > the SwigObject and the wrapping object. > > In this case it's something like > '_gnc_numeric *' at 0x7f11908da840> > > and > > > When I have the GncNumeric object I can access the SwigObject through its > instance property. > The other way round seems not as simple. > > My method __gncnumeric__str__ overwrites the __str__ method using add_method. > > In this method self points to the swig object. I cannot use the methods of > GncNumeric as > it is the layer of the wrapping object. > > To access these methods I used to instantiate a GncNumeric(instance=self) as > a temporary self. > But that seems not right as this probably already exists. > > I wondered if I could know about the wrapping object when I had the instance > only. I did not > find a way. I stumbled over an interesting comment in > https://github.com/Gnucash/gnucash/blob/69fef8277fde56e7d2df700b21c63c19c115852a/bindings/python/function_class.py#L50 > > # why reimpliment __new__? Because later on we're going to > # use new to avoid creating new instances when existing instances > # already exist with the same __instance value, or equivalent __instance > # values, where this is desirable... > > I did not find "later on". But if that works I can safely do > GncNumeric(instance=self) as it > would reuse the existing GncNumeric object. > > But nevertheless I wondered if we could put a link to the GncNumeric in the > Swig Level. I tried > it: > https://github.com/c-holtermann/gnucash/commit/a6c2adf7d29c4367728a4fa920307ee595eefa5a > (link to my fork) > > Interstingly some Swig objects can be added to and some others not. > GncNumeric works while > QofSession doesn't. So I made it a try block for now. > > Having done that I can get to the GncNumeric (sort of higher self) from the > Swig object: > https://github.com/c-holtermann/gnucash/commit/2f35b550709ad4131aca0e7309f6bb4b0f984b84 > > Well I found it interesting to think these things through. Maybe someone can > tell me about > the mysterious "later on" in the cited comment. At this point I find it > useful to have a > way from the instance to the wrapping object through some kind of link as I > suggested in > the patch to function_class. Christoph, The person who wrote the first two lines of that, Mark Jenkins, was the original source of the Python bindings. He was never a regular dev, he just got 16 patches committed between 2007 and 2012, 10 of which touched the python bindings. Your history with them is almost as long as his--in fact you have *12* commits--and pretty much no one else has done anything serious with them. In other words, if anyone knows, it’s you! Just to add some more confusion, there’s now a C++ class GncNumeric that handles the actual implementation of many of the gnc_numeric.* functions. I believe that SWIG can’t see it, only the C wrapper functions are exposed to SWIG. Regards, John Ralls ___ gnucash-devel mailing list gnucash-devel@gnucash.org https://lists.gnucash.org/mailman/listinfo/gnucash-devel
