cross-language-portlisted

# Skill: cross-language porting **Trigger.** The user asks to *port this*, *translate to [Language]*, *rewrite in [Language]*, *convert this to [Language]*, *reimplement X in [Language]*, or *give me the [Language] equivalent*. > **Reference material** (the full cross-language idiom-mapping matrix, > per-language porting notes + landmines, the equivalence-harness recipes, > and the data-boundary/FFI contracts): see `reference.md` in this > directory. This file is the doctrine + the execution loop; `reference.md` > is the lookup and the recipes. ## Objective Port a specific module, script, CLI, or function from a **source** language to a **target** language so that: 1. **Behaviour is preserved exactly** — same inputs produce same outputs, same errors, same side-effect ordering. This is proven, not asserted (see §4). 2. **The output is idiomatic** — it reads as if a senior engineer *native to the target language* wrote it from the spec, not transliterated line-for-line from the source. 3. **It lands green** — formatted, linted, and tested with the target language's own toolchain before you call it done. ## Supported languages (the fleet) Every one is a first-class **source and target**. Anchor per language — full toolchain rows (formatter / linter / test runner / package manager / error model / async model / HTTP / JSON) are in `reference.md` §R1. | Language | Idiom anchor | Format · Lint · Test | |---|---|---| | **Rust** | ownership, `Result<T,E>` + `?`,