Yeah, I've seen %__MODULE__{} in a few places too
I just realised that it is also possible to do something like
defmodule Chat.Channel do
defstruct name: "", public?: true
@me __MODULE__
def connect(%@me{name: name} = channel) do
# ...
end
end
пʼятниця, 21 січня 2022 р. о 19:08:20 UTC [email protected] пише:
> __MODULE__ is the right answer here IMHO. It is consistent with the other
> "meta constants" like __ENV__, __DIR__ __FILE__ and so on in that they
> desugar to constants, but are file / code relative. It isn't a super common
> pattern, but last time I checked generated phoenix code does a
> %__MODULE__{} pattern match check on the changeset functions.
>
> On Friday, January 21, 2022 at 6:56:42 AM UTC-5 [email protected] wrote:
>
>> Thanks for the tip Wojtek
>> Aliasing __MODULE__ should work in my case
>>
>> As far as I understand this pattern isn't used too often(at least
>> projects like Plug or Ecto don't use it), so I guess it is not really
>> considered as idiomatic
>>
>> I just feel that if you are inside a module there should be a shortcut
>> built-in in the language(like when you call other functions from the module
>> you don't specify the full path) but it might be just old instincts from
>> other languages
>>
>> пʼятниця, 21 січня 2022 р. о 10:58:56 UTC Wojtek Mach пише:
>>
>>> Neither `%_{}` nor `%self{}` can be supported because they already have
>>> a meaning in pattern matches. The former means _any_ struct and the latter
>>> binds the matched struct name to the variable `self`.
>>>
>>> You can give `__MODULE__` another name with an alias:
>>>
>>> alias __MODULE__, as: Struct
>>>
>>> def connect(%Struct{} = channel)
>>>
>>>
>>> On January 21, 2022, "gmail.com" <[email protected]> wrote:
>>>
>>> It is common to define a struct together with various functions that
>>> access that struct in the module:
>>>
>>> defmodule Chat.Channel do
>>> defstruct name: "", public?: true
>>>
>>> def new do
>>> %Chat.Channel{name: "Untitled"}
>>> end
>>>
>>> def connect(%Chat.Channel{} = channel) do
>>> IO.inspect(channel)
>>> end
>>> end
>>>
>>> It is also common to alias the struct for easier access
>>>
>>> defmodule Chat.Channel do
>>> defstruct name: "", public?: true
>>>
>>> alias Chat.Channel
>>>
>>> # ...
>>> end
>>>
>>> But, say, renaming the module would require manually replacing all
>>> struct occurrences with the new module name. Aliasing can help, but if the
>>> last bit should be updated too(say Chat.Channel should be updated to
>>> Chat.Room) it would still require to manually replace everything.
>>>
>>> There is a workaround to use __MODULE__, but IMO the code looks a bit
>>> ugly
>>>
>>> defmodule Chat.Channel do
>>> defstruct name: "", public?: true
>>>
>>> def new do
>>> %__MODEUL__{name: "Untitled"}
>>> end
>>>
>>> def connect(%__MODEUL__{} = channel) do
>>> IO.inspect(channel)
>>> end
>>> end
>>>
>>> I think It would be great to have some kind of shortcut(syntactic sugar)
>>> to access the struct within the module.
>>> First I thought about something like %_(%%, %. etc) but this way it
>>> looks a bit cryptic
>>>
>>> def connect(%_{} = channel) do
>>>
>>> So maybe something like %self would work
>>>
>>> defmodule Chat.Channel do
>>> defstruct name: "", public?: true
>>>
>>> def new do
>>> %self{name: "Untitled"}
>>> end
>>>
>>> def connect(%self{} = channel) do
>>> IO.inspect(channel)
>>> end
>>> end
>>>
>>> What do you think?
>>>
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