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Subject: Infix Operator "^" - here's what applications do
Tomas Mecir: > The ^ operator used to be right-associative in KSpread, but then, as a > follow-up to the earlier discussions, I have changed it to be > left-associative. Thus, at least some applications are already > affected by what was discussed earlier. Right. I don't want to say "we can't revisit decisions"; sometimes new information compels us to do so. But on the other hand, I think we should NOT change a previous decision unless there is a STRONG COMPELLING REASON to do so. Otherwise we'll never finish. I spent some time trying to collect REAL data, which I think will at least give us a hand. Here are the results of tests with real spreadsheets and "^". There are two basic issues: * Is prefix "-" higher precedence than "^"? - Higher means that -2^2 = (-2)^2 = 4 - Lower means that -2^2 = -(2^2) = -4 * Is "^" evaluated left-to-right or right-to-left? - Left means 2^3^4 = (2^3)^4 =4096 - Right means 2^3^4 = 2^(3^4) = 2.42E+024 I retyped these two equations into various spreadsheets (I retyped them, to prevent compensating when converting a file), namely =-2^2 and =2^3^4. Here are the results, in no particular order: Excel 2003: higher, left OOo 2.1: higher, left wikiCalc version 0.97 of 2006-11-14: higher, left Lotus 1-2-3, v9.8.0208.1200: lower, left Quattro Pro 12 (native mode): lower, left (PalmOS) DocumentToGo SheetToGo: lower, left Gnumeric 1.6.3: higher, right KDE KSpread 1.6.1: higher, right [BUT KSpread has switched to left-to-right since then] I think we NEED to define these two issues, instead of leaving them undefined/requiring parens in all cases, in the exchange format. Obviously, user interfaces can do something different. The precedence of "-" is obviously debated, but I think we should choose "higher". The left-to-rightness is less contested if you weight these equally; in any case, I think we should choose "left". Both are our current values, so in other words, I'm arguing for the status quo. I believe we should leave things as they are (higher and left). Comments? --- David A. Wheeler
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