> Changing idioms > 2py3 changes idioms that are "outdated". When running the script it changes > type(t) != type(q) to not isinstance(t, type(q)). Is this this something I > should do? > > Python syntax > The 2to3 scripts have the possibility to change the comma-syntax to correct > python syntax. For example, it changes (a,b) to (a, b). Should I run this on > the files as well?
Those are things that Python2 linters like pep8 pyflakes flake8 usually bring up too. I would say that getting FEniCS clean w.r.t. to those three (largely overlapping) improves the code readability and quality. Cheers, Nico On Fri, Jun 27, 2014 at 9:21 AM, Aslak Bergersen <[email protected]> wrote: > Hi! > > I have some questions about the supporting to python 3.x. You can take a > look at the changes I have done if you want (or need). > > Testing with python 3.3 > I have installed python 3.3 such that I can use it when I want (e.g. py3 > script.py). However, when I'm running the tests all the dependencies are > missing (For now I'm running python -3). So how do I build it with python 3? > > Support python 3.1 > callable() returned in python 3.2, so there is no need to change it, unless > we want to support python 3.1? > > Changing idioms > 2py3 changes idioms that are "outdated". When running the script it changes > type(t) != type(q) to not isinstance(t, type(q)). Is this this something I > should do? > > Python syntax > The 2to3 scripts have the possibility to change the comma-syntax to correct > python syntax. For example, it changes (a,b) to (a, b). Should I run this on > the files as well? > > Six module > I have used the six modules to make it compatible with 2.x and 3.x, but I'm > a bit unsure where to put it, or how to properly include it to the project > such that all files have access. > > -- > Mvh > Aslak Bergersen > 993 22 848 > > > 2014-05-23 12:56 GMT+02:00 Martin Sandve Alnæs <[email protected]>: > >> UFL doesn't use __metaclass__ but it uses __new__, is the behaviour of >> that the same? I'd like to clean up those parts at some point but I won't >> have time before the summer. >> >> If we have to change behaviour of Expression we should consider doing that >> simultaneously with the introduction of an Expression-like ufl type which >> will have several advantages. >> >> Martin >> >> >> On 23 May 2014 12:24, Johan Hake <[email protected]> wrote: >>> >>> And then there is the change of syntax for metaclasses in Python3... Just >>> goggle metaclass python 3 and there are several pointers to the different >>> syntax. >>> >>> Maybe this will be a good point to throw out the usage of metaclasses in >>> DOLFIN? What we need is to add a distinction between CompiledExpression and >>> Expression. I have tried this before with no luck ;) >>> >>> Johan >>> >>> >>> On Thu, May 22, 2014 at 11:40 AM, Martin Sandve Alnæs >>> <[email protected]> wrote: >>>> >>>> Yes, and if we're lucky we can get to that point without as much work as >>>> sympy, since we don't have as much code. >>>> >>>> The 2to3 tool can do selective changes like change print "" to print("") >>>> and fix exception syntax, which are compatible with 2.7. >>>> >>>> It can also do things like change "a = dict.iteritems()" into "a = >>>> dict.items()" which changes the memory usage when run on 2.7. These >>>> differences can instead be resolved by using the python module "six" which >>>> implements cross-compatible helper functions for a lot of things. >>>> >>>> Btw when we switch we should go straight to python 3.3-3.4. >>>> Supporting 3.0-3.2 side by side with 2.7 is apparently harder. >>>> >>>> (Note to Aslak: read the link from Jan!) >>>> >>>> Martin >>>> >>>> >>>> On 22 May 2014 11:22, Jan Blechta <[email protected]> wrote: >>>>> >>>>> Note that there is also an approach of having simultaneously 2.x and >>>>> 3.x >>>>> compatible codebase without a need of using 2to3. Allegedly, this is >>>>> used in SymPy, NumPy and SciPy projects. See >>>>> >>>>> http://ondrejcertik.blogspot.cz/2013/08/how-to-support-both-python-2-and-3.html >>>>> >>>>> Jan >>>>> >>>>> >>>>> On Thu, 22 May 2014 11:05:43 +0200 >>>>> Martin Sandve Alnæs <[email protected]> wrote: >>>>> >>>>> > The plan for the initial work here is to keep the code python 2.7 >>>>> > compatible but ready for a later swift switch to 3 only. I suggest we >>>>> > release fenics 1.5 with python 2.7 compatibility intact but >>>>> > convertible to python 3 by just running py2to3. Otherwise there will >>>>> > be too much simultaneous breakage. Then we can discuss whether we >>>>> > leave python 2.7 behind in fenics 1.6 or not. >>>>> > >>>>> > However, I haven't thought about the swig side in dolfin, and as >>>>> > Johan >>>>> > mentions keeping the Python CAPI code compatible is not covered by >>>>> > py2to3. I'll discuss this with Johan and Aslak. >>>>> > >>>>> > Martin >>>>> > >>>>> > >>>>> > On 22 May 2014 10:49, Garth N. Wells <[email protected]> wrote: >>>>> > >>>>> > > Nice. Do we want to support Python 2.7 and 3, or would it be more >>>>> > > sustainable to go all Python 3? My preference is for simplicity and >>>>> > > low maintenance, which points to Python 3 only support. >>>>> > > >>>>> > > Garth >>>>> > > On Thu, 22 May, 2014 at 9:39 AM, Martin Sandve Alnæs >>>>> > > <[email protected]> wrote: >>>>> > > >>>>> > >> We have a summer intern at Simula, Aslak Bergersen, >>>>> > >> who will work on preparations for python 3 support in FEniCS, >>>>> > >> as well as some other FEniCS tasks, from late June and >>>>> > >> throughout July. >>>>> > >> >>>>> > >> The preparations for python 3 involves mainly: >>>>> > >> - Replacing ScientificPython for AD in FIAT >>>>> > >> - Applying and committing backwards compatible parts of py2to3 >>>>> > >> - Replacing several functions such as dict.iteritems with >>>>> > >> six.iteritems in UFL and possibly FFC to make sure we keep the >>>>> > >> same performance and memory behaviour with python 2 and 3. >>>>> > >> >>>>> > >> I will be on vacation part of his time here so please >>>>> > >> help him out if he has questions to the list. >>>>> > >> >>>>> > >> Martin >>>>> > >> >>>>> > > >>>>> > > >>>>> >>>> >>>> >>>> _______________________________________________ >>>> fenics mailing list >>>> [email protected] >>>> http://fenicsproject.org/mailman/listinfo/fenics >>>> >>> >> > > > > -- > Mvh > Aslak Bergersen > 993 22 848 > > > _______________________________________________ > fenics mailing list > [email protected] > http://fenicsproject.org/mailman/listinfo/fenics > _______________________________________________ fenics mailing list [email protected] http://fenicsproject.org/mailman/listinfo/fenics
