Nim Flavoured Lisp

NFL is a Lisp dialect that compiles to Nim. It processes s-expressions into Nim AST via macros, giving you Lisp syntax with full access to the Nim ecosystem and type system. Inspired by Hylang. Docs are hosted here, and release builds are here.

Quick example

(import std/strutils)

(proc greet ((name string)) (: string)
  (toUpperAscii name))

(echo (greet "nfl"))

Compile and run:

nfl compile hello.nfl && ./hello
# NFL

Building

Requires Nim >= 2.2.4.

nimble build

This produces a bin/nfl binary. To run it against a file:

nfl check   file.nfl   # type-check only
nfl compile file.nfl   # compile to binary

Documentation

• Getting Started — installation, first program, core concepts
• Language Reference — all language forms
• Macro System — writing and using macros
• Nim Interop — calling Nim stdlib, dot notation, exports, pragmas
• CLI Reference — every nfl subcommand and flag
• The REPL — nfl repl's interactive session model
• Package Layout — organizing application and library projects
• API documentation is generated from source via nimble docs (see man/api.md) into docs/, served via GitHub Pages
• Changelog — notable changes per release

Examples

The examples/ directory contains runnable .nfl programs covering types, loops, error handling, macros, pragmas, and Nim interop.

License

NFL — Nim Flavoured Lisp
Copyright (C) 2025 George Watson

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.