Problems using struct pack/unpack in files, and reading them.

[Ian Kelly]

On Fri, Nov 13, 2015 at 10:40 PM, Steven D'Aprano <steve at pearwood.info> wrote:
> Python has operator overloading, so it can be anything you want it to be.
> E.g. you might have a DSL where +feature turns something on and -feature
> turns it off.

By that argument we should also have operators ~, !, $, \, ? because
some hypothetical DSL might someday want to use them for something.

> Decimal uses it to force the current precision and rounding, regardless of
> what the number was initiated to:
>
> Counter uses it to strip zero and negative counts:
>
> I would expect that symbolic maths software like Sympy probably has use of a
> unary plus operator, but I'm not sure.

Unary plus as normalization does not strike me as being very
intuitive. I never would have known about any of these if I hadn't
read the Counter case in the docs, and then I only remembered it
because it because it seemed janky. Unary minus on Counters is even
weirder, by the way: it first negates the signs of all the values, and
*then* normalizes by removing non-positive values. Who has ever needed
that?

For somebody reading one of these uses of unary plus in real code, I
imagine it would be a bit of a WTF moment if it's the first time
they've encountered it. I don't recall ever seeing any code that
actually used this, though.

> I might consider stealing an idea from Perl and Javascript, and have unary
> plus convert strings to a number:
>
> +"123"
> => returns int 123
> +"1.23"
> => returns float 1.23

Eww.