Swe Programming Fsharp

F# Coding Standards

Purpose

Progressive disclosure of F# coding standards for agents writing F# code.

Authoritative Source: docs/explanation/software-engineering/programming-languages/f-sharp/README.md

Usage: Auto-loaded for agents when writing F# code. Provides quick reference to idioms, best practices, and antipatterns.

Prerequisite Knowledge

IMPORTANT: This skill provides OSE Platform-specific style guides, not educational tutorials.

You MUST understand F# fundamentals before using these standards. Complete the AyoKoding F# learning path first:

1. F# Learning Path - Initial setup, language overview, quick start guide (0-95% language coverage)
2. F# By Example - 75+ annotated code examples (beginner to advanced patterns)

What this skill covers: OSE Platform naming conventions, framework choices, repository-specific patterns, how to apply F# knowledge in THIS codebase.

What this skill does NOT cover: F# syntax, language fundamentals, generic patterns (those are in ayokoding-web).

See: Programming Language Documentation Separation for content separation rules.

Quick Standards Reference

• Naming, DUs, Railway, Pipeline — naming conventions, discriminated unions, railway-oriented programming, pipeline operator
• Records, Async, Formatting, Testing — immutable records, async workflows, Fantomas formatting, Expecto/FsCheck testing

Comprehensive Documentation

Authoritative Index: docs/explanation/software-engineering/programming-languages/f-sharp/README.md

Mandatory Standards (All F# Code MUST Follow)

1. Coding Standards - F# naming conventions, module organization, pipeline idioms
2. Testing Standards - Expecto, FsCheck property-based testing, AltCover coverage
3. Code Quality Standards - Fantomas, FSharpLint, exhaustive pattern matching
4. Build Configuration - .fsproj file order, dotnet CLI, Nx integration

Context-Specific Standards (Apply When Relevant)

1. Error Handling Standards - Result type, railway-oriented programming, computation expressions
2. Concurrency Standards - Async workflows, MailboxProcessor, Task interop
3. Functional Programming Standards - Computation expressions, monads, applicatives
4. Type Safety Standards - DUs, units of measure, phantom types
5. Performance Standards - Tail recursion, sequences, lazy evaluation
6. Security Standards - Type-driven validation, Giraffe authentication
7. API Standards - Giraffe HttpHandler composition, Saturn routing
8. DDD Standards - DU-based domain modeling, making illegal states unrepresentable

Related Skills

• docs-applying-content-quality
• repo-practicing-trunk-based-development

References

• F# README
• Functional Programming