or can be called as in the [Compiling Agda](#compiling-agda) section.
If you want to use a library in your home directory (for instance if it is a development version) then typecheck it manually (using `agda.withPackages` if necessary) and then override the `src` attribute of the package to point to your local repository.
More information can be found in the [official Agda documentation on library management](https://agda.readthedocs.io/en/v2.6.1/tools/package-system.html).
Agda modules can be compiled with the `--compile` flag. A version of `ghc` with `ieee754` is made available to the Agda program via the `--with-compiler` flag.
*`everythingFile` can be used to specify the location of the `Everything.agda` file, defaulting to `./Everything.agda`. If this file does not exist then either it should be patched in or the `buildPhase` should be overridden (see below).
*`libraryName` should be the name that appears in the `*.agda-lib` file, defaulting to `pname`.
*`libraryFile` should be the file name of the `*.agda-lib` file, defaulting to `${libraryName}.agda-lib`.
By default, Agda sources are files ending on `.agda`, or literate Agda files ending on `.lagda`, `.lagda.tex`, `.lagda.org`, `.lagda.md`, `.lagda.rst`. The list of recognised Agda source extensions can be extended by setting the `extraExtensions` config variable.
To add an Agda package to `nixpkgs`, the derivation should be written to `pkgs/development/libraries/agda/${library-name}/` and an entry should be added to `pkgs/top-level/agda-packages.nix`. Here it is called in a scope with access to all other Agda libraries, so the top line of the `default.nix` can look like:
This library has a file called `.agda-lib`, and so we give an empty string to `libraryFile` as nothing precedes `.agda-lib` in the filename. This file contains `name: IAL-1.3`, and so we let `libraryName = "IAL-1.3"`. This library does not use an `Everything.agda` file and instead has a Makefile, so there is no need to set `everythingFile` and we set a custom `buildPhase`.
When writing an Agda package it is essential to make sure that no `.agda-lib` file gets added to the store as a single file (for example by using `writeText`). This causes Agda to think that the nix store is a Agda library and it will attempt to write to it whenever it typechecks something. See [https://github.com/agda/agda/issues/4613](https://github.com/agda/agda/issues/4613).