Boyko Bantchev wrote: "I am not sure that 'cm' or other unit designations have to do with conventional or other algebraic notation, but if they do, and if you draw parallels with J, what in J corresponds to 'cm'? Also, what is 'the J convention for omitting parentheses' and how is it 'better'?" Well, 'cm' is a product, c*m, where c=.0.01 and m is a meter. The conventional rule is that multiplication is done before addition and exponentiation is done before multiplication. The square centimeter, cm^2=(c*m)^2 is an exception from the rule. The J convention is that expressions are evaluated from right to left: a*b+c means a*(b+c). It is better because is is simpler and more general.
- Bo >________________________________ > Fra: Boyko Bantchev <boyk...@gmail.com> >Til: programm...@jsoftware.com >Sendt: 21:39 lørdag den 8. december 2012 >Emne: Re: [Jprogramming] J v Python > >On 8 December 2012 18:36, Bo Jacoby <bojac...@yahoo.dk> wrote: >> Conventional algebraic notation is sometimes confusing. mc^2 means m*(c^2) , >> mass times light speed squared, while cm^2 means square centimeter, (c*m)^2, >> rather than centi squaremeter, c*(m^2). The J convention for omitting >> parentheses is better. > >I am not sure that 'cm' or other unit designations have to do >with conventional or other algebraic notation, but if they do, >and if you draw parallels with J, what in J corresponds to 'cm'? > >Also, what is 'the J convention for omitting parentheses' and how >is it 'better'? >---------------------------------------------------------------------- >For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
