Generic strings/regex patterns in strings

Currently, we have str and LiteralStr. These don't do a good job expressing the range of values a string may have. Let's say we have the following function:

Email: TypeAlias = str

def send_email(email: Email) -> int:
    # Send an email
    ...

# passes
send_email("test@example.com")

# passes
send_email("badddd")

# passes even if unknown_var is only identified as `str`
send_email(unknown_var)

We could improve it by having something like this:

# This is a bad regex pattern, but you get the idea :)
Email: TypeAlias = str['[a-z0-9]+@[a-z0-9]+\.[a-z0-9]+']

def send_email(email: Email) -> int:
    # Send an email
    ...

# passes
send_email("test@example.com")

# fails
send_email("badddd")

# passes even if unknown_var is only identified as `str`
send_email(unknown_var)

A static type checker would be able to validate strings passed in by code. I would imagine this idea can be extended to Pattern and Match generics as well, but I haven't thought too deeply about them yet.

If we don't want to make str generic, we could add a new type to typing called StrPattern. We would need it anyways to backport to typing_extensions.

Aucun fichier d’implémentation ni test n’est nommé. Commencez par examiner la gestion existante de str et de LiteralStr, ainsi que les conventions de typing_extensions ; déterminez si la fonctionnalité utilise un str générique ou un nouveau type StrPattern, et définissez le comportement attendu pour les littéraux, les variables, Pattern et Match avant d’identifier les tests qui démontrent que le travail est terminé.