Thank You, Guido

Re:Thank You, Guido by riazrizvi on Wednesday October 30, 2019 @03:12PM (#21401385)

Regarding string, the breaking change was necessary because it was a double-duty type, sometimes acting as a byte-array and other times acting as a string. Meaning some of its functions, like string.length(), gave a value that only made sense for string-as-byte-array, but not as string-as-simple-list-of-characters. More detail on Stackoverflow if you want (https://stackoverflow.com/questions/5471158/typeerror-str-do...). Anyhow the double-duty type needed to be disambiguated into two separate types, a breaking change.

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Re:Thank You, Guido by papln on Wednesday October 30, 2019 @03:44PM (#21401725)

string.length() still doesn't make sense in Python 3

There's nothing "simple" about "list of characters" in Unicode. Discussed at length at: https://news.ycombinator.com/item?id=18154667

Here's how a Unicode export with 20 years of experience in Unicode explained it: https://blog.golang.org/strings

> Some people think Go strings are always UTF-8, but they are not: only string literals are UTF-8. As we showed in the previous section, string values can contain arbitrary bytes; as we showed in this one, string literals always contain UTF-8 text as long as they have no byte-level escapes.

> In fact, the definition of "character" is ambiguous and it would be a mistake to try to resolve the ambiguity by defining that strings are made of characters.

> [Exercise: Put an invalid UTF-8 byte sequence into the string. (How?) What happens to the iterations of the loop?]

If you aren't in Unicode, then "character" is the same as "byte" so splitting the types gets you nothing of vlaue.

Assuming you are not implementing a low-level Unicode library, what's your use case for "list of Unicode characters" ?

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Re:Thank You, Guido by microcolonel on Wednesday October 30, 2019 @04:43PM (#21402463)

Even in Unicode-aware applications, it is generally not that useful to segment just by codepoint, you more often really want to segment by extended grapheme cluster.

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Re:Thank You, Guido by takeda on Wednesday October 30, 2019 @04:02PM (#21401913)

In python 2.7 they also introduced "bytes" although it was just another alias to "str". I wonder if they would make python 2.7 distinguish between them and add an option (like another import from __future__) to throw errors when these types were mixed.

This would help a lot in preparing code incrementally to work on python3.

In the mean time, mypy in python 2 mode doesn't warn about str <-> bytes either :/

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