On 21 May 2013 14:14, Vitja Makarov <vitja.maka...@gmail.com> wrote: > > > > 2013/5/21 mark florisson <markflorisso...@gmail.com> >> >> On 21 May 2013 11:26, Vitja Makarov <vitja.maka...@gmail.com> wrote: >> > Hi! >> > >> > Recently I've started work on new type inference engine. Now it's almost >> > ready and I want to discuss it. >> > >> > It works like this: first infer type for each assignment then for whole >> > entry. It has some advantages over previous algorithm: >> > - it handles assignment cycles, see test_swap() for example >> > - it can infer type using info about assignments on the whole entry: >> > >> > a = 1 >> > b = a >> > a = "str" >> > >> > a is python object and b is integer. >> > >> > Here are testcases that show some new cases it can solve: >> > >> > https://github.com/vitek/cython/blob/_type_inference_new/tests/run/type_inference_new.pyx >> > >> > Here is branch for it >> > https://github.com/vitek/cython/tree/_type_inference_new >> > >> > -- >> > vitja. >> > >> > _______________________________________________ >> > cython-devel mailing list >> > cython-devel@python.org >> > http://mail.python.org/mailman/listinfo/cython-devel >> > >> >> Hey Vitja, >> >> Cool! How do you want to handle variable merge at control flow joins? >> Would you promote (backwards incompatible), use a union type, or >> object? E.g. what does this result in: >> >> x = 0 >> for i in range(N): >> x += 0.2 * i >> print typeof(x) > > > Hi Mark, > > Nothing changed in your example old algorithm was able to handle this > "simple" kind of cycles as well as new one: > > def foo(int N): > x = 0 > for i in range(N): > x += 0.2 * i > print typeof(x) > > So this function (not that N is an integer here) will print 'dobule'. > > With new algorithm we can go further: > > def foo(int N): > x = 1 > y = 0 > for i in range(N): > x = x * 0.1 + y * 0.2 > y = x * 0.3 + y * 0.4 > print typeof(x), typeof(y) > > Here both x and y will be inferred as double >
Ok, so I assume it promotes the incoming types (all reaching definitions)? If N == 0, then when using objects you get an int, otherwise a double. What happens when the reaching types cannot be promoted together? Do you fall back to object? > -- > vitja. > > _______________________________________________ > cython-devel mailing list > cython-devel@python.org > http://mail.python.org/mailman/listinfo/cython-devel > _______________________________________________ cython-devel mailing list cython-devel@python.org http://mail.python.org/mailman/listinfo/cython-devel
