On Fri, Aug 19, 2016 at 5:01 AM Lawrence D’Oliveiro <lawrenced...@gmail.com> wrote:
> It is handy to be able to keep complex expressions together sometimes, > when breaking them up would simply obscure their structure. To avoid lines > getting long, why not take advantage of the two available screen/page > dimensions to make their structure clearer? As a bonus, spacing out > parentheses makes them look less of a clutter. > > > Examples from < > https://github.com/ldo/qahirah_examples/blob/master/operators>: > > A function call with complex arguments (specifying arguments by keywords > is highly recommended here): > > rect_1_pattern = \ > qah.Pattern.create_linear \ > ( > p0 = (0, 0), > p1 = (major_dim, 0), > colour_stops = > ( > (0, rect_1_colour), > (1, complement(rect_1_colour)), > ) > ) > I'd rather have intermediate variables and avoid the non-semantic indentation. p0 = (0, 0) p1 = (major_dim, 0) colour_stops = (0, rect_1_colour), (1, complement(rect_1_colour)) rect_1_pattern = qah.Pattern.create_linear(p0, p1, colour_stops) Computing a variable value (using redundant parentheses to avoid > backslash-continuations): > > dest_rect = \ > ( > draw_bounds > + > Vector(col, row) * draw_bounds.dimensions > + > Vector(0, top_extra) > ) > I'd rather have one long line for this case, even if it's "too long" by PEP 8 standards. If it's too long to think about, I'd break the task into parts, each with a well-considered variable name. substep = a + b final = substep + c From <https://github.com/ldo/python_pixman/blob/master/pixman.py>, a > complex condition (with redundant parentheses again): > > if ( > not isinstance(src, Image) > or > mask != None and not isinstance(mask, Image) > or > not isinstance(dest, Image) > ) : > raise TypeError("image args must be Image objects") > #end if > No need for the separate calls to isinstance, nor the check for None. if any(not isinstance(obj, Image) for obj in [src, mask, dest]): ... If you prefer maps to comprehensions: is_image = lambda obj: isinstance(obj, Image) if any(map(is_image, [src, mask, dest])): ... -- https://mail.python.org/mailman/listinfo/python-list
