PyWart: More surpises via "implict conversion to boolean" (and other steaming piles!)

[Ian Kelly]

On Feb 12, 2014 9:16 PM, "Steven D'Aprano" <steve at pearwood.info> wrote:
>
> On Tue, 11 Feb 2014 07:36:34 -0800, Travis Griggs wrote:
>
> > On Feb 10, 2014, at 10:30 PM, Steven D'Aprano <steve at pearwood.info>
> > wrote:
> >
> >
> >>>    1. Parenthesis should not be required for parameter- less
> >>>    functions.
> >>
> >> Of course they should. Firstly, parameter-less functions are a code-
> >> smell, and ought to be discouraged. Secondly, even if you have a good
> >> reason for using one -- for example, random.random -- then the
> >> difference between referring to the object and calling the object
> >> should be clear.
> >
> > Interesting. Can you clarify or provide some links to the
> > "parameter-less functions are a code-smell" bit?
>
>
> Functions map a value to another value. They can be one-to-one, or many-
> to-one. (Mathematically, they cannot be one-to-many or many-to-many,
> that's called a relation.) What about zero-to-one?
>
> If the function always returns the same result, e.g.:
>
> def spam():
>     return "spam spam spam"

That's still one-to-one. There is no such thing as a zero-to-one mapping.

Mathematical functions map a single value to a single value. To represent
multi-argument functions then, the single input takes on the value of an
ordered sequence. The input value of a 0-argument function then is the
empty sequence.
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