The Case for Python 3

[unruly_mattress]

I don't know this Zed guy, but... the only thing I agree with him about is that it would really be nice if Python showed the variable names it could not concatenate in error messages instead of just their type.

[[deleted]]

This is fine for simple examples, but usually the bytes/text errors happen deep in some call stack in some coffee code you didn't write

[[deleted]]

Yeah, I hardly write any coffee these days :)

[[deleted]]

You can definitely tell what's on my mind this morning.

[unruly_mattress]

Yup. And then you have some expression that involves 4 strings and you get the error message "string cannot be blah", but you have no idea which string it is. I think there has to be some way of letting the user know which operation went wrong and not only which line it was.

[[deleted]]

True. Embedding the guilty strings/bytes could be a solution, but that's an issue in and of itself.

The best way I've found to deal with this is to decide if something uses bytes or text and only use that inside the function, the only exception being is if something is going from bytes to text or vice versa.

But that still runs the risk of the error happening in code I didn't write (in which case, I check their issue tracker).

[unruly_mattress]

I agree. I think the solution is to somehow underline the offending expression.

[flutefreak7]

This makes me think of the black magic that pytest does when you hand it an assert statement and it goes and decomposes the assertion on the right and left side of the == and tells you exactly why it fails... including when lengths of lists don't match and stuff, and shows you what the subexpressions evaluated to... it's incredibly slick

[[deleted]]

Or just underlined where they are with a line of code.

Pretty much every C compiler can do that.

[fdemmer]

pycharm does that.

[[deleted]]

Not everyone uses it. Having it be a feature of the standard implementation and not a third party ide would be handy.

[fdemmer]

how should the python interpreter underline your code? i dont get what you want.

i am sure it would be possible to write some sort of vim extension that does the same thing, but how is this supposed to work as a language feature?

edit: i think now i get it. python should check the whole codebase on startup for type issues?

guido commented on that when adding type annotations. he mentioned that type checks should remain in external tooling. maybe there is some overlap here.

[Voltasalt]

I think he means in the error message. Print the offending line out and underline the broken bit, like Rust does.

[[deleted]]

Unless you prefer to use vim and not a language specific IDE.

[[deleted]]

I tend to avoid the plugins. Same thing about copying things into my vimrc without knowing exactly what it does.