Stream: beginners

Topic: Import aliases

Agus Zubiaga (Mar 07 2023 at 14:54):

Is there a way to alias a module import?

Agus Zubiaga (Mar 07 2023 at 14:56):

I made Bytes.Decode and Bytes.Encode modules which expose functions with shared names, e.g. Bytes.Decode.u16 and Bytes.Encode.u16

Agus Zubiaga (Mar 07 2023 at 14:57):

I can't do Bytes.Decode.{u16} and expose them unqualified because it would clash with Bytes.Encode.u16

Folkert de Vries (Mar 07 2023 at 14:57):

you can at least use these functions in a qualified way

Folkert de Vries (Mar 07 2023 at 14:58):

I'm not sure if aliasing of imports themselves works

Agus Zubiaga (Mar 07 2023 at 14:58):

Right, yeah. I'm just wondering whether there is a way to alias so I don't have to type the full module name.

Agus Zubiaga (Mar 07 2023 at 14:59):

Is that something intentionally left out?

Agus Zubiaga (Mar 07 2023 at 15:02):

I can see some drawbacks with aliasing myself. I'm curious about what would be the recommendation for cases like this

Folkert de Vries (Mar 07 2023 at 15:02):

I don't think it's intentional, no

Folkert de Vries (Mar 07 2023 at 15:03):

though qualifying functions is encouraged in roc (like in elm)

Folkert de Vries (Mar 07 2023 at 15:03):

here you could just alias in the actual code of your module, as a stopgap

Agus Zubiaga (Mar 07 2023 at 15:04):

Gotcha

Agus Zubiaga (Mar 07 2023 at 15:20):

In Elm, I'm used to aliasing Json.Encode to JE and Json.Decode to JD, but that might be more a habit than anything else.

Agus Zubiaga (Mar 07 2023 at 15:22):

In this case, I wanted to write:

msgDecoder =
    messageType <- BD.await BD.u8
    messageLength <- BD.await BD.i32

    when messageType is
        'R' ->
            authMsgDecoder

        _ ->
            BD.succeed (UnknownMessageType messageType)

authMsgDecoder =
    success <- BD.await BD.i32

    if success == 0 then
        BD.succeed AuthenticationOk
    else
        BD.succeed AuthenticationFailed

Folkert de Vries (Mar 07 2023 at 15:23):

right, and Bytes.Encode as BE does not work ?

Agus Zubiaga (Mar 07 2023 at 15:24):

No, I get a syntax error:

13│          pg.Bytes.Decode as BD,
                             ^

I am expecting a comma or end of list, like

    imports [Shape, Vector]⏎

Folkert de Vries (Mar 07 2023 at 15:26):

ok. @Richard Feldman we would want this to work, right?

Richard Feldman (Mar 07 2023 at 18:36):

yes!

Richard Feldman (Mar 07 2023 at 18:36):

it's just never been implemented :sweat_smile:

Luke Boswell (Mar 08 2023 at 09:16):

Added an issue #5105 to track this.

Last updated: Jul 06 2025 at 12:14 UTC