gleam-lang/gleam

Avoid calling `bitArraySliceToFloat` in generated JS for float patterns

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#4,658 opened on Jun 2, 2025

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help wanted

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Description

Today when using a :float bit array pattern the bitArraySliceToFloat function is called twice with the same arguments. This is wasted work!

Change the code generator to do it only once, saving the result to a variable to use twice.

Contributor guide

Research direction
Locate the generated JavaScript code in the Gleam compiler that calls bitArraySliceToFloat twice for float patterns, refactor to call once and store the result in a variable.
Tech stack
rustjavascript
Domain
tooling
Issue type
Performance
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
RustGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
75