Nim Coding Practices

Nim Coding Practices

Application skill for NEP-1 style learning (from the archived awesome-guidelines style capsules). For legacy codebases with non-NEP spellings, prefer --styleCheck:usages over full NEP-1 enforcement until migrated.

Core Principle

Nim library quality is guessable names + mechanical layout, PascalCase types, camelCase API, result assignments, compiler styleCheck in CI.

When to Use / NOT

• Nim packages, stdlib-shaped libraries, CLI/tools targeting NEP-1 conventions.
• Setting up --styleCheck, testament/nim test, nimble CI.

NOT when:

• Generated Nim from c2nim/other translators, validate generators.
• One-off scripts with local conventions, apply layout/naming lightly.

Workflow

1. Layout, 2-space, 80 cols, multiline breaks (nim-style-formatting-layout.md).
2. Naming/types, PascalCase, enums, init/new (nim-style-naming-types.md).
3. Procedures, result, let, API verbs (nim-style-procedures-api.md).
4. Modules/verify, std imports, styleCheck (nim-style-modules-verify.md).
5. Verify, nim c --styleCheck:error, tests on changed modules.

Red Flags

• Tab indentation
• Lines > 80 without wrap
• Manual column-aligned type blocks
• Shouting acronyms (parseURL)
• existsFile verbSubject order
• Unprefixed non-pure enum members
• Exception without CatchableError/Defect lineage
• var when value never reassigned
• Macro/template where proc suffices
• Terminal return instead of result =
• getLen / append instead of len / add
• Missing m prefix on mutating views
• import os without std/ for stdlib
• Inconsistent identifier spelling across file
• Triple-quote content glued to opener line
• Unnecessary spaces in a .. b
• Undocumented exported procs

Verification

• nim c --styleCheck:error [--styleCheck:usages] <files>
• Project test command (nim test, testament, nimble task)
• 80-column and 2-space spot check on changed hunks
• Capsule checklist on public API naming (fileExists, initFoo, newFoo)

References

• awesome-guidelines/references/nim-style-learning-note.md
• awesome-guidelines/references/nim-style-formatting-layout.md
• awesome-guidelines/references/nim-style-naming-types.md
• awesome-guidelines/references/nim-style-procedures-api.md
• awesome-guidelines/references/nim-style-modules-verify.md