On Wed, Aug 10, 2011 at 1:25 PM, Duncan Booth <duncan.booth@invalid.invalid> wrote: > Chris Angelico <ros...@gmail.com> wrote: > >> On Wed, Aug 10, 2011 at 10:56 AM, Dan Sommers <d...@tombstonezero.net> >> wrote: >>> In terms of easier to read, I find code easier to read when the >>> operators are at the beginnings of the lines (PEP 8 notwithstanding): >>> >>> x = (someobject.somemethod(object3, thing) >>> + longfunctionname(object2) >>> + otherfunction(value1, value2, value3)) >>> >> >> Without the parentheses, this is legal but (probably) useless; it >> applies the unary + operator to the return value of those functions. > > No, in some other languages it might be legal, but this is Python. > without the parentheses it is a syntax error.
It would be parsed as three separate statements. The only reason it would be a syntax error would be because of the indentation, which is not what I'd call reliable; it happens to catch this case, because assignment doesn't allow subsequent lines to be indented, but nothing forces continuation lines to be indented. x = (5 +4) x = 5 +4 What we have is a strangeness that can arise when a programmer ignores something that is often insignificant; spare parentheses usually don't matter. Another potential danger is the similarity with tuple creation: x = (someobject.somemethod(object3, thing) + longfunctionname(object2) + otherfunction(value1, value2, value3),) This is a tuple with one element. Not too bad with the + operator, but imagine if everything's done with method chaining on . which results in the , being nearly indistinguishable. Not an insurmountable problem, but a potential risk. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
