On 4/1/18 4:31 PM, Brendan Barnwell wrote: > On 2018-04-01 05:36, Steven D'Aprano wrote: >> On Sun, Apr 01, 2018 at 08:08:41AM -0400, Richard Damon wrote: >> >>> One comment about the 'combitorial explosion' is that it sort of >>> assumes >>> that each individual combination case needs to be handled with distinct >>> code. >> >> No -- as I said in an earlier post, Terry and I (and Eric) are talking >> about the explosion in number of prefixes, not the complexity of the >> code. >> >> You are right that many of the prefixes can be handled by the same code: >> >> rfd rfD rFd rFD rdf rdF rDf rDF >> Rfd RfD RFd RFD Rdf RdF RDf RDF >> frd frD fRd fRD fdr fdR fDr fDR >> Frd FrD FRd FRD Fdr FdR FDr FDR >> drf drF dRf dRF dfr dfR dFr dFR >> Drf DrF DRf DRF Dfr DfR DFr DFR >> # why did we support all these combinations? who uses them? >> >> presumably will all handled by the same "raw dedent f-string" code. But >> the parser still has to handle all those cases, and so does the person >> reading the code. >> >> And that *mental complexity* is (in my opinion) the biggest issue with >> adding a new d-prefix, and why I would rather make it a method. > > That doesn't seem a very reasonable argument to me. That is like > saying that a person reading code has to mentally slog through the > cognitive burden of understanding "all the combinations" of "a + b + > c", "a + b - c", "a * b + c", "a - b * c", etc. We don't. We know > what the operators mean and we build up our understanding of > expressions by combining them. Similarly, these string prefixes can > mostly be thought of as indepedent flags. You don't parse each > combination separately; you learn what each flag means and then build > up your understanding of a prefix by combining your understanding of > the flags. (This is also glossing over the fact that many of the > combinations you list differ only in case, which to my mind adds no > extra cognitive load whatsoever.) > Actually ALL the variation listed were the exact same prefix (dfr) with the 6 variations in possible order and the 8 variation of each of those in case. Which just shows why you don't want to try to exhaustive list prefixes.
-- Richard Damon _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
