On Thu, Oct 17, 2019 at 02:08:56PM +0200, Anders Hovmöller wrote:
> Well obviously never with literals. But most cases of multiplication
> aren't with literals. So how can you get a type error when doing
>
> a*b
>
> is the real question.
Actually, the real question is, why are you using such clearly
unsuitable and non-descriptive variable names and blaming the confusion
caused by poor names on the syntax?
Borrowing from the PEP, how would you get a type-error from these?
width + margin
prefix + word
If you did, the cause would clearly be a bug in your code, not the fault
of the syntax.
In my experience, the most common use for the repetition operator in
strings involves a single, literal, character:
dashes = '-'*count
> And the answer is now obvious: any time the programmer thinks a and b
> are numbers but they are not.
And this is a fault of the syntax, how? If repetition was spelled:
a.repeat(b)
and the programmer thought a was a string, when it was actually a float,
and thought b was an int, but it was actually None, would you conclude
that "method calls are a mistake" because they cause type errors?
I'm sure you would agree with me that this is a bogus argument. Type
errors are a sign of a bug in the code regardless of the spelling: you
think a value has a different type than it actually has't.
If it is a bogus argument for method calls, it is a bogus argument for
operators.
> That's a logical type error that now propagates and it's very hard to
> track down the offending line when you eventually end up with a crash
> in a different module because
And that's an argument against any form of type polymorphism. I expected
a list, but got a string, and len(a) didn't raise TypeError therefore
"functions are a mistake".
--
Steven
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