# Scala Coding Practices

> Use when authoring or reviewing Scala, 2-space layout, camelCase naming, accessor/mutator conventions, explicit public types, immutable case classes, Option over null, and Scaladoc on public API.

- Skill: `ryan-brosas/scala-coding-practices` (Agent Skill)
- Install (CLI): `npx skillmds@latest add ryan-brosas/scala-coding-practices`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ryan-brosas/scala-coding-practices/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: ryan-brosas (https://skillmd.com/u/ryan-brosas)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/ryan-brosas/scala-coding-practices

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# Scala Coding Practices

Application skill for Scala style learning (from the archived `awesome-guidelines` style capsules). For Spark/Akka/ZIO stack patterns, load stack capsules under `skills/*-foundation`.

## Core Principle

Scala readability is **official layout/naming plus functional safety**, immutable data, explicit public types, expression-oriented control, documented API.

## When to Use / NOT

- Scala application/library source, Scalafmt/Scalafix/wartremover CI.
- Reviewing naming, types, case classes, control flow, Scaladoc.

**NOT when:**

- Non-Scala code.
- Generated boilerplate, validate generators instead.
- Spark-internal perf micro-optimizations, use the Databricks guide in stack capsules under `skills/*-foundation`.

## Workflow

1. **Format & layout**, 2-space, wraps, control spacing (`scala-style-formatting-layout.md`).
2. **Naming**, packages, accessors, parentheses (`scala-style-naming-packages.md`).
3. **Types**, inference rules, immutability, Option (`scala-style-types-immutability.md`).
4. **Control & docs**, return, for, Scaladoc, errors (`scala-style-control-api.md`).
5. **Verify**, Scalafmt/Scalafix + `sbt test` / `sbt compile` on changed modules.

## Red Flags

- Tabs or 4-space indent
- Java getter/setter names in Scala API
- Side-effect nullary method without `()`
- Symbolic operators in domain API
- `var` in case class
- Missing `override`
- Public method without return type
- `Option.get` / `null`
- `return` in closures
- Public API without Scaladoc

## Verification

- Scalafmt/Scalafix on changed files
- Compile + tests for touched projects
- Capsule checklist on public API review


## References

- `awesome-guidelines/references/scala-style-learning-note.md`
- `awesome-guidelines/references/scala-style-formatting-layout.md`
- `awesome-guidelines/references/scala-style-naming-packages.md`
- `awesome-guidelines/references/scala-style-types-immutability.md`
- `awesome-guidelines/references/scala-style-control-api.md`