Re: Calc: `*' binds more strongly than `/'

[Jay Belanger]

Christian Schlauer <address@hidden> writes:
> Jay Belanger <address@hidden> writes:
...
>> Well, I think that's the proper way of doing it; even though there are
>> rules for interpreting expressions like a*b/c*d, that doesn't mean
>> writing the expression that way is a good thing to do -- it's just bad
>> form.  I don't think there is any difference between Calc's current
>> precedence rule and the more standard one for properly written
>> expressions.
>
> I did some more `research', and a*b/c*d is not bad form, and it is a
> properly written expression, see Wikipedia. Let me cite from
> <http://en.wikipedia.org/wiki/Order_of_operations#Examples_from_arithmetic>:

As I said, there are rules for interpreting the above expressions.  
I also said that avoiding the parentheses is bad form; note that the
wikipedia article also says:

  Proper use of parentheses and other grouping symbols

  When restricted to using a straight text editor, parentheses (or
  more generally "grouping symbols") must be used generously to make
  up for the lack of graphics, like square root symbols. Here are some
  rules for doing so: 

  1) Whenever there is a fraction formed with a slash, put the
  numerator (the number on top of the fraction) in one set of
  parentheses, and the denominator (the number on the bottom of the
  fraction) in another set of parentheses. This is not required for
  fractions formed with underlines: 
    y = (x+1)/(x+2)
  ...
  5) An exception to the rules requiring parentheses applies when only
  one character is present. While correct either way, it is more
  readable if parentheses around a single character are omitted: 

    y = (3)/(x) or y = 3/x

    y = (3)/(2x) or y = 3/(2x)

> So besides Excel, Gnumeric, MATLAB, all pocket calculators, Wikipedia
> agrees with me, too.

Well, wikipedia also says

  Calculators

  Different calculators follow different orders of operations.

and gives several examples.

The reason for Calc's current behavior is because Dave Gillespie,
Calc's author, thought of "a b / c d" as representing 
  a b
  ---
  c d
To have it represent "a(b/c)d", the parentheses can (and, according to
wikipedia, should be) put in.  For those that really don't like
parentheses, an option to allow the user to decide for themselves the
relative precedence of * and / in Calc will be added, of course.

Jay