2011/5/28 Robert Bradshaw <rober...@math.washington.edu>: > On Fri, May 27, 2011 at 3:32 PM, Stefan Behnel <stefan...@behnel.de> wrote: >> Hi, >> >> I recently stumbled over a tradeoff question with AttributeError, and now >> found the same situation for UnboundLocalError in Vitja's control flow >> branch. So here it is. >> >> When we raise an exception several times in different parts of the code with >> a message that only differs slightly each time (usually something like >> "'NoneType' has no attribute X", or "local variable X referenced before >> assignment"), we have three choices to handle this: >> >> 1) Optimise for speed: create a Python string object at module >> initialisation time and call PyErr_SetObject(exc_type, msg_str_obj). >> >> 2) Current way: let CPython create the string object when raising the >> exception and just call PyErr_SetString(exc_type, "complete message"). >> >> 3) Trade speed for size and allow the C compiler to reduce the storage >> redundancy: write only the message template and the names as C char* >> constants by calling PyErr_Format(exc_type, "message template %s", "X"). >> >> Assuming that exceptions should be exceptional, I'm leaning towards 3). This >> would allow the C compiler to collapse multiple usages of the same C string >> into one data constant, thus reducing a bit of redundancy in the shared >> library size and the memory footprint. However, it would (slightly?) slow >> down the exception raising due to the additional string formatting, even >> when compared to the need to build a Python string object that it shares >> with 2). While 1) would obviously be the fastest way to raise an exception >> (no memory allocation, only refcounting), I think it's not worth it for >> exceptions as it increases both the runtime memory overhead and the module >> startup time. >> >> Thoughts? > > Any back-of-the-envelope calculations on how much the savings would > be? I think I'm leaning towards 3 as well, certainly not option 1. >
For UnboundLocalError and NameError I used 2) way: https://github.com/vitek/cython/commit/1fe86b85d965753244cd09db38b1089b40f09a58 So maybe I should add functions like __Pyx_RaiseUnboundLocalError and __Pyx_RaiseClosureNameError that will use 3) way. How do you like put_error_if_unbound CCodeWriter method is that right place for it? -- vitja. _______________________________________________ cython-devel mailing list cython-devel@python.org http://mail.python.org/mailman/listinfo/cython-devel
