Example Nix Plugin

This repo is based on nix-plugins by Shea Levy

This repo contains an example Nix plugin that adds a new builtin called example_op. This op currently contains a print on load for debugging, but that should probably be removed in proper use.

How?

There is not much published on how to properly write nix plugins, what functions are available to a developer, etc. When writing this basic example plugin I used shlevy's nix-plugins repo for the CMake build and the official primops source code for primop implementation examples.
This repo currently only has a plugin compiling for Nix 2.26 (updated from nix-plugins which supports 2.24). This version can be changed in the default.nix, though imports and types will likely need to be updated.

Testing with eval

$ nix eval --expr 'builtins.example_op "saluton" "mondo"' --extra-plugin-files "$(nix-build --no-out-link)/lib/nix/plugins/"
Plugin Registered
{ hello = "world"; hola = "mundo"; saluton = "mondo"; }

Access repl

nix repl --extra-plugin-files "$(nix-build --no-out-link)/lib/nix/plugins/"