.. _sect-packages: ********Packages******** Idris includes a simple build system for building packages and executablesfrom a named package description file. These files can be used with theIdris compiler to manage the development process. Package Descriptions==================== A package description includes the following: + A header, consisting of the keyword ``package`` followed by a package  name. Package names can be any valid Idris identifier. The iPKG  format also takes a quoted version that accepts any valid filename. + Fields describing package contents, ``<field> = <value>``. At least one field must be the modules field, where the value is acomma separated list of modules. For example, given an idris package``maths`` that has modules ``Maths.idr``, ``Maths.NumOps.idr``,``Maths.BinOps.idr``, and ``Maths.HexOps.idr``, the correspondingpackage file would be: ::     package maths     modules = Maths            , Maths.NumOps            , Maths.BinOps            , Maths.HexOps  Other examples of package files can be found in the ``libs`` directoryof the main Idris repository, and in `third-party libraries<https://github.com/idris-lang/Idris-dev/wiki/Libraries>`_.  Using Package files=================== Idris itself is aware about packages, and special commands areavailable to help with, for example, building packages, installingpackages, and cleaning packages.  For instance, given the ``maths``package from earlier we can use Idris as follows: + ``idris2 --build maths.ipkg`` will build all modules in the package + ``idris2 --install maths.ipkg`` will install the package, making it  accessible by other Idris libraries and programs. + ``idris2 --clean maths.ipkg`` will delete all intermediate code and  executable files generated when building. Once the maths package has been installed, the command line option``--package maths`` makes it accessible (abbreviated to ``-p maths``).For example: ::     idris2 -p maths Main.idr Package Dependencies Using Atom=============================== If you are using the Atom editor and have a dependency on another package,corresponding to for instance ``import Lightyear`` or ``import Pruviloj``,you need to let Atom know that it should be loaded. The easiest way toaccomplish that is with a .ipkg file. The general contents of an ipkg filewill be described in the next section of the tutorial, but for now here isa simple recipe for this trivial case: - Create a folder myProject. - Add a file myProject.ipkg containing just a couple of lines: .. code-block:: idris     package myProject     pkgs = pruviloj, lightyear - In Atom, use the File menu to Open Folder myProject.