Sorry for all the misspellings...
2014-03-17 22:32 GMT+01:00 Christophe Bal <projet...@gmail.com>: > Hello, > and what about something like that ? > > a @ b @ c -> (a @ b) @ c > a * b @ c -> (a * b) @ c > a @ b * c -> a @ (b * c) > > Easy to remember. The *-product has priority to @-product, and then we > just to @-product from left to right. > > An advantage of this is that parsers do job from left to right so I realy > think that is a better choice than the weak-right. > > Christophe BAL > > > > 2014-03-17 21:37 GMT+01:00 Russell E. Owen <ro...@uw.edu>: > > In article >> <CAPJVwBkLww7-ysZB76LMRZ+mmbyN_5T=ym_vu1pjgakrlbq...@mail.gmail.com>, >> Nathaniel Smith <n...@pobox.com> wrote: >> >> > OPTION 1 FOR @: >> > Precedence: same as * >> > Associativity: left >> > My shorthand name for it: "same-left" (yes, very creative) >> > >> > This means that if you don't use parentheses, you get: >> > a @ b @ c -> (a @ b) @ c >> > a * b @ c -> (a * b) @ c >> > a @ b * c -> (a @ b) * c >> > >> > OPTION 2 FOR @: >> > Precedence: more-weakly-binding than * >> > Associativity: right >> > My shorthand name for it: "weak-right" >> > >> > This means that if you don't use parentheses, you get: >> > a @ b @ c -> a @ (b @ c) >> > a * b @ c -> (a * b) @ c >> > a @ b * c -> a @ (b * c) >> > >> > OPTION 3 FOR @: >> > Precedence: more-tightly-binding than * >> > Associativity: right >> > My shorthand name for it: "tight-right" >> > >> > This means that if you don't use parentheses, you get: >> > a @ b @ c -> a @ (b @ c) >> > a * b @ c -> a * (b @ c) >> > a @ b * c -> (a @ b) * c >> > >> > We need to pick which of which options we think is best, based on >> whatever >> > reasons we can think of, ideally more than "hmm, weak-right gives me >> warm >> > fuzzy feelings" ;-). (In principle the other 2 possible options are >> > tight-left and weak-left, but there doesn't seem to be any argument in >> > favor of either, so we'll leave them out of the discussion.) >> >> After seeing all the traffic on this thread, I am in favor of >> "same-left" because it is easiest to remember: >> - It introduces no new rules. >> - It is unambiguous. If we pick option 2 or 3 we have no strong reason >> to favor one over the other, leaving users to guess. >> >> To my mind, being able to easily reason about code you are reading is >> more important that hoping to increase efficiency for one common case >> when not using parenthesis. >> >> It also has the advantage that it needs the least justification. >> >> -- Russell >> >> _______________________________________________ >> NumPy-Discussion mailing list >> NumPy-Discussion@scipy.org >> http://mail.scipy.org/mailman/listinfo/numpy-discussion >> > >
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