Stream: ideas

Topic: Partial module params

Kilian Vounckx (Jan 01 2025 at 14:36):

I was wondering if this is supported, planned or neither. Suppose I want to import a module Foo:

module {
    given_foo,
    given_bar,
} -> [
    gotten_foo,
    gotten_bar,
    gotten_baz,
]

gotten_foo = \x -> given_foo x 1
gotten_bar = \x -> given_bar x 1
gotten_baz = \x -> x + 1

However, I only want to use the gotten_foo function. Is there a need to provide the given_bar function?

Or even more extremely, why would I need to provide module params at all if I only want to use gotten_baz?

Brendan Hansknecht (Jan 01 2025 at 15:08):

I don't think that is planned. If you need those split up for more granular use, they should be in different modules

Brendan Hansknecht (Jan 01 2025 at 15:09):

Module params are the contract of the module. Even if you only use a small portion of the functions, you have to fill the full contract.

Brendan Hansknecht (Jan 01 2025 at 15:10):

Also, allowing partial imports would mean that it is a breaking change for the module author to call given_bar in gotten_baz.

Brendan Hansknecht (Jan 01 2025 at 15:11):

That seems like it would make the package ecosystem much more painful. Way more things would become breaking changes.

Brendan Hansknecht (Jan 01 2025 at 15:12):

Of course if you want to do the equivalent of a partial import, you can just make all other functions call crash

Kilian Vounckx (Jan 01 2025 at 20:35):

Brendan Hansknecht said:

Also, allowing partial imports would mean that it is a breaking change for the module author to call given_bar in gotten_baz.

Did not think of this!

Kilian Vounckx (Jan 01 2025 at 20:36):

Anyway, thanks for the reply. It makes sense after hearing your points

Last updated: Jun 16 2026 at 16:19 UTC