feat: add SendExt to reduce boilerplate of common send() calls
#4
Comments
No Traits?In Rust, we have this cool thing called trait. // discord.abc.Messageable
trait Messageable {
fn send(...) -> Message;
}
trait SendExt: Messageable {
fn send_info(...) -> Message { self.send(...) }
fn send_warn(...) -> Message { self.send(...) }
fn send_error(...) -> Message { self.send(...) }
}
impl<T: Messageable> SendExt for T {}
// now we can use `send_{info, warn, error}()` on every Messageable
user.send_info("Prepare thyself")
context.send_warn("Thy end is now")
textchannel.send_error("Judgement")Now, how am I supposed to do something similar to this in Python, |
Coping Mechanism CandidatesTrait at home:
A mixin class with Edit: |
The Seething ProcessPython is not Rust. Pretending as if it is or "hacking" it with things like That said, making As a compromise, I'm going to create a custom context class which subclasses
|
Malding ImplementationQuestion: How do I put trait bounds on a mixin class? In other words, if a mixin depends on method(s) of the mixed-into class,
Can I enforce this with Python's type hints and static type checkers? |
Attempt 1from abc import ABC, abstractmethod
# discord.abc.Messageable
class Messageable:
def send(self, content: str) -> None:
print(content)
# commands.Context
class Context(Messageable):
pass
class SendExt(ABC):
@abstractmethod
def send(self, content: str) -> None: ...
def send_warn(self, content: str) -> None:
self.send(f"WARN: {content}")
# custom `Context` to inject `send_*()`
class MacLak(Context, SendExt):
pass
ctx = MacLak()
ctx.send_warn("I am inside your walls")As seen in the unresolved SSO question, one way is to make # try to mixin `SendExt` without implementing `.send()`
class Nope(SendExt):
pass
nope = Nope() # fails; cannot be instantiated without overriding all @abstractmethodProblems
# can `.send()` to DM
class User(Messageable):
pass
steven = User()
# incompatible type; can be used with duck typing but Pyright is still mad
SendExt.send_warn(steven, "Only language you speak is FAILURE") |
Attempt 2Type hinting the class SendExt(Protocol):
def send_warn(self: Messageable, content: str) -> None:
self.send(f"WARN: {content}")The |
Attempt 3
from abc import abstractmethod
from typing import Protocol
# discord.abc.Messageable
class Messageable(Protocol):
def send(self, content: str) -> None:
print(content)
@abstractmethod
def _get_channel(self, ident: int) -> None: ...
# commands.Context
class Context(Messageable):
def _get_channel(self, ident: int) -> None:
print(f"Context: {ident}")
# send_ext.py
class SendExt(Messageable, Protocol):
def send_warn(self: Messageable, content: str) -> None:
self.send(f"WARN: {content}")This allows us to:
# custom `Context` to inject `send_*()`
class MacLak(Context, SendExt):
pass
ctx = MacLak()
ctx.send_warn("Directly available as a method")
class NotMessageable(SendExt):
pass
# the `Messageable._get_channel` abstract method is not overriden
try:
_ = NotMessageable() # type: ignore[abstract]
except TypeError:
print("Does not override `_get_channel()`, cannot be instantiated")
class User(Messageable):
def _get_channel(self, ident: int) -> None:
print(f"User: {ident}")
user = User()
SendExt.send_warn(user, "Still able to use `SendExt.*()` as a function")ProblemThere is a tiny problem. It turns out... discord.abc.Messageable is actually neither # current state (v2.3.2) of discord.py
class Messageable:
def send(self, content: str) -> None:
print(content)
def _get_channel(self, ident: int) -> None:
raise NotImplementedErrorIt's just a normal class, and the required method |
Investigation
I assume it was because most features of Removing the |
Lessons LearnedHere's an MRE version of what I struggled to achieve so far: trait Foo {
fn foo(&self);
}
trait Bar: Foo {
fn bar(&self) {
self.foo();
}
}from abc import abstractmethod
from typing import Protocol
class Fooable(Protocol):
@abstractmethod
def foo(self):
...
class BarMixin(Foo, Protocol):
def bar(self: Foo):
self.foo()Combination of Honestly, it's kind of depressing to see Rust/Python snippets right next to each other, Well, I could have just suppressed the warnings and get along with duck typing, |
send_ext - reduce boilerplate of common .send() callsSendExt to reduce boilerplate of common send() calls
SendExtMixinProvides convenience function to send embed with predefined color palette and icon.
send_code()- Send code blocksend_info()- Ordinary responsessend_warn()- Invalid use of a featuresend_err()- Critical failure; Found a bugThe text was updated successfully, but these errors were encountered: