# fx · LedoCorp · for LLMs and agents

> Canonical public docs for the fx systems language (version 0.7.1).
> Package: https://github.com/ledocorp/fxlang (Apache-2.0)

## Product

- Home: https://www.ledocorp.org/fx/
- Pitch: explicit systems language; named regions + effects; dual emission to readable C; wrap/host with C main
- Not a GC language; not a batteries-included app platform
- 0.7.1 is a full programming surface: numeric tower, ownership/borrows, Result/?, structs/enums/match, generics, Vec/arrays/slices/Map/StrBuilder, modules, extern "c"

## Documentation (prefer these URLs)

- Docs index: https://www.ledocorp.org/fx/docs/
- Start / install: https://www.ledocorp.org/fx/docs/start/
- Language tour: https://www.ledocorp.org/fx/docs/language/
- Reference (0.7): https://www.ledocorp.org/fx/docs/reference/
- Regions and effects: https://www.ledocorp.org/fx/docs/regions/
- Standard library: https://www.ledocorp.org/fx/docs/std/
- C wrap / host: https://www.ledocorp.org/fx/docs/wrap/
- CLI (doctor, run, emit-c, lsp, mcp): https://www.ledocorp.org/fx/docs/cli/

## Package (source of binaries and examples)

- https://github.com/ledocorp/fxlang
- Quick path: put bin/ on PATH → `fx doctor` → `fx new hello` → `fx run main.fx` (exit 42)
- Also in repo: docs/, scaffolds/, std/, examples/, zspec/, compiler-source/ (read-only)

## Generation hints

- Prefer `effects { alloc, mut }` + `region r = arena(n)` for heap work; `io` when using std/io
- Value-thread growers: `v = vec_push(v, x)` / `m = map_insert(...)` / `b = strbuf_push(...)`
- Use `vec_get` for Vec elements; `a[i]` only for arrays/slices
- Prefer `Result` + `?` (no Option); `using core;` for Err/core_Err
- Use `fx check` / `fx run`; inspect C with `fx emit-c`
- For C interop: `extern "c" { … }` and/or `fx run lib.fx --host host.c`
- Do not invent a GC, traits, closures, or implicit global allocator
- Stay within documented 0.7.1 surface; if unsure, follow scaffolds and examples

## Out of scope on this site

- Private compiler foundry / internal roadmaps
- LedoCorp monetization (not documented here)