gleam-lang/gleam

Re-export types and values from other modules

Open

#614 opened on May 28, 2020

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 (27 comments) (13 reactions) (0 assignees)Rust (21,417 stars) (960 forks)batch import
discussionhelp wanted

Description

It would be nice to be able to re-export a type or function from another module.

Here's an idea for a syntax:

// one.gleam
pub type MyType {
  MyConstructor
}

pub fn my_function() -> Nil {
  Nil
}

// two.gleam

import two.{pub MyType, pub MyConstructor, pub my_function}

Questions

Should it be permitted to export only a subset of a type's constructors? This would mean it would not possible for users to pattern match on all records as only some have been exported. The above syntax would allow that.

Contributor guide

Tech stack
rust
Domain
developer experience
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Knowledge of RustUnderstanding of Gleam's module systemFamiliarity with compiler internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
Study the current import/export infrastructure in the Gleam compiler, likely in the `src/` directory, focusing on how modules are resolved and how symbols are exposed. Explore existing GitHub issue comments for design considerations, particularly regarding whether to allow exporting only a subset of a type's constructors. A proposed syntax is given in the issue; implementing it would involve parsing new syntax and modifying the compiler's name resolution and type checking phases.