Erlang Coding Practices

Erlang Coding Practices

Application skill for Erlang style learning (from the archived awesome-guidelines style capsules). For supervision trees and release tooling, combine with OTP stack capsules in skills/*-foundation.

Core Principle

Erlang quality is pattern-visible modules + crash-loud bugs, explicit exports, clause-driven control flow, and restrictive matching on every boundary.

When to Use / NOT

• Erlang/OTP applications, libraries, and src/*.erl modules.
• Setting up Elvis, Dialyzer, xref, rebar3 test/dialyzer in CI.

NOT when:

• Elixir code, use elixir-coding-practices (BEAM overlap on security only).
• Generated .app / protobuf stubs, validate generators.

Workflow

1. Layout, indent, types/records, grouping (erlang-style-formatting-modules.md).
2. Names & types, snake/CamelCase, specs, opaque state (erlang-style-naming-types.md).
3. Control flow, clauses, try/catch, no if (erlang-style-control-flow.md).
4. OTP & security, exports, API wrap, input safety (erlang-style-otp-security.md).
5. Verify, Elvis, Dialyzer, xref, rebar3 test on changed modules.

Red Flags

• -compile(export_all) or -import
• camelCase functions or snake_case variables
• Records/types in .hrl
• Cross-module raw gen_server:call
• Giant top-level case or if
• case catch / legacy catch / control-flow throw
• Boolean function parameters
• binary_to_atom/1 on external input
• binary_to_term/1 without [safe] on untrusted data
• Catch-all _ when return set is known
• _ = on fallible standard-library calls
• Debug io:format in src/
• God modules or macros for module names

Verification

• rebar3 dialyzer / project Dialyzer profile
• Elvis (Inaka rules or project config)
• xref / cross-reference check where configured
• rebar3 eunit or Common Test on changed modules
• Capsule checklist on exported -spec list

References

• awesome-guidelines/references/erlang-style-learning-note.md
• awesome-guidelines/references/erlang-style-formatting-modules.md
• awesome-guidelines/references/erlang-style-naming-types.md
• awesome-guidelines/references/erlang-style-control-flow.md
• awesome-guidelines/references/erlang-style-otp-security.md