# Nimble [![Build Status](https://travis-ci.org/nim-lang/nimble.svg?branch=master)](https://travis-ci.org/nim-lang/nimble)

Nimble is a *beta*-grade *package manager* for the [Nim programming
language](https://nim-lang.org).

Interested in learning **how to create a package**? Skip directly to that section
[here](#creating-packages).

## Contents

- [Requirements](#requirements)
- [Installation](#installation)
- [Nimble usage](#nimble-usage)
  - [nimble refresh](#nimble-refresh)
  - [nimble install](#nimble-install)
  - [nimble uninstall](#nimble-uninstall)
  - [nimble build](#nimble-build)
  - [nimble c](#nimble-c)
  - [nimble list](#nimble-list)
  - [nimble search](#nimble-search)
  - [nimble path](#nimble-path)
  - [nimble init](#nimble-init)
  - [nimble publish](#nimble-publish)
  - [nimble tasks](#nimble-tasks)
  - [nimble dump](#nimble-dump)
- [Configuration](#configuration)
- [Creating Packages](#creating-packages)
  - [Project structure](#project-structure)
    - [Tests](#tests)
  - [Libraries](#libraries)
  - [Binary packages](#binary-packages)
  - [Hybrids](#hybrids)
  - [Dependencies](#dependencies)
    - [External dependencies](#external-dependencies)
  - [Nim compiler](#nim-compiler)
  - [Versions](#versions)
    - [Releasing a new version](#releasing-a-new-version)
- [Publishing packages](#publishing-packages)
- [.nimble reference](#nimble-reference)
  - [[Package]](#package)
    - [Required](#required)
    - [Optional](#optional)
  - [[Deps]/[Dependencies]](#depsdependencies)
    - [Optional](#optional)
- [Troubleshooting](#troubleshooting)
- [Nimble's folder structure and packages](#nimbles-folder-structure-and-packages)
- [Repository information](#repository-information)
- [Contribution](#contribution)
- [About](#about)

## Requirements

Nimble has some runtime dependencies on external tools, these tools are used to
download Nimble packages. For instance, if a package is hosted on
[GitHub](https://github.com), you need to have [git](https://www.git-scm.com)
installed and added to your environment ``PATH``. Same goes for
[Mercurial](http://mercurial.selenic.com) repositories on
[Bitbucket](https://bitbucket.org). Nimble packages are typically hosted in Git
repositories so you may be able to get away without installing Mercurial.

**Warning:** Ensure that you have a fairly recent version of Git installed.
If the version is older than 1.9.0, then Nimble may have trouble using it.
See [this issue](https://github.com/nim-lang/nimble/issues/105) for more
information.

## Installation

Nimble is now bundled with [Nim](https://nim-lang.org)
(since Nim version 0.15.0).
This means that you should have Nimble installed already, as long as you have
the latest version of Nim installed as well. Because of this **you likely do
not need to install Nimble manually**.

But in case you still want to install Nimble manually, you can follow the
following instructions.

There are two ways to install Nimble manually. The first is using the
``koch`` tool included in the Nim distribution and
[repository](https://github.com/nim-lang/Nim/blob/devel/koch.nim).
Simply execute the following command to compile and install Nimble.

```
./koch nimble
```

This will clone the Nimble repository, compile Nimble and copy it into
Nim's bin directory.


## Nimble usage

Once you have Nimble installed on your system you can run the ``nimble`` command
to obtain a list of available commands.

### nimble refresh

The ``refresh`` command is used to fetch and update the list of Nimble packages
(see below). There is no automatic update mechanism, so you need to run this
yourself if you need to *refresh* your local list of known available Nimble
packages.  Example:

    $ nimble refresh
    Downloading package list from https://.../packages.json
    Done.

Some commands may remind you to run ``nimble refresh`` or will run it for you if
they fail.

You can also optionally supply this command with a URL if you would like to use
a third-party package list.

Package lists can be specified in Nimble's config. Take a look at the
config section below to see how to do this.

### nimble check

The ``check`` command will read your package's .nimble file. It will then
verify that the package's structure is valid.

Example:

    $ nimble check
        Error: Package 'x' has an incorrect structure. It should contain a single directory hierarchy for source files, named 'x', but file 'foobar.nim' is in a directory named 'incorrect' instead. This will be an error in the future.
         Hint: If 'incorrect' contains source files for building 'x', rename it to 'x'. Otherwise, prevent its installation by adding `skipDirs = @["incorrect"]` to the .nimble file.
      Failure: Validation failed



### nimble install

The ``install`` command will download and install a package. You need to pass
the name of the package (or packages) you want to install. If any of the
packages depend on other Nimble packages Nimble will also install them.
Example:

    $ nimble install nake
    Downloading nake into /tmp/nimble/nake...
    Executing git...
    ...
    nake installed successfully

Nimble always fetches and installs the latest version of a package. Note that
latest version is defined as the latest tagged version in the Git (or Mercurial)
repository, if the package has no tagged versions then the latest commit in the
remote repository will be installed. If you already have that version installed,
Nimble will ask you whether you wish it to overwrite your local copy.

You can force Nimble to download the latest commit from the package's repo, for
example:

    $ nimble install nimgame@#head

This is of course Git-specific, for Mercurial, use ``tip`` instead of ``head``. A
branch, tag, or commit hash may also be specified in the place of ``head``.

Instead of specifying a VCS branch, you may also specify a version range, for
example:

    $ nimble install nimgame@"> 0.5"

In this case a version which is greater than ``0.5`` will be installed.

If you don't specify a parameter and there is a ``package.nimble`` file in your
current working directory then Nimble will install the package residing in
the current working directory. This can be useful for developers who are testing
locally their ``.nimble`` files before submitting them to the official package
list. See the [Creating Packages](#creating-packages) section for more info on this.

#### Package URLs

A valid URL to a Git or Merurial repository can also be specified, Nimble will
automatically detect the type of the repository that the url points to and
install it.

For repositories containing the Nimble package in a subdirectory, you can
instruct Nimble about the location of your package using the ``?subdir=<path>``
query parameter. For example:

    $ nimble install https://github.com/nimble-test/multi?subdir=alpha

### nimble develop

The ``develop`` command allows you to link an existing copy of a package into
your installation directory. This is so that when developing a package you
don't need to keep reinstalling it for every single change.

    $ cd ~/projects/jester
    $ nimble develop

Any packages depending on ``jester`` will now use the code in
``~/projects/jester``.

If you specify a package name to this command, Nimble will clone it into the
current working directory.

    $ nimble develop jester

The ``jester`` package will be cloned into ``./jester`` and it will be linked
to your installation directory.

Just as with the ``install`` command, a package URL may also be specified
instead of a name.

### nimble uninstall

The ``uninstall`` command will remove an installed package. Attempting to remove
a package which other packages depend on will result in an error. You can use the
``--inclDeps`` or ``-i`` flag to remove all dependent packages along with the package.

Similar to the ``install`` command you can specify a version range, for example:

    $ nimble uninstall nimgame@0.5

### nimble build

The ``build`` command is mostly used by developers who want to test building
their ``.nimble`` package. This command will build the package with default
flags, i.e. a debug build which includes stack traces but no GDB debug
information. The ``install`` command will build the package in release mode
instead.

### nimble c

The ``c`` (or ``compile``, ``js``, ``cc``, ``cpp``) command can be used by
developers to compile individual modules inside their package. All options
passed to Nimble will also be passed to the Nim compiler during compilation.

Nimble will use the backend specified in the package's ``.nimble`` file if
the command ``c`` or ``compile`` is specified. The more specific ``js``, ``cc``,
``cpp`` can be used to override that.

### nimble list

The ``list`` command will display the known list of packages available for
Nimble. An optional ``--ver`` parameter can be specified to tell Nimble to
query remote Git repositories for the list of versions of the packages and to
then print the versions. Please note however that this can be slow as each
package must be queried separately.

### nimble search

If you don't want to go through the whole output of the ``list`` command you
can use the ``search`` command specifying as parameters the package name and/or
tags you want to filter. Nimble will look into the known list of available
packages and display only those that match the specified keywords (which can be
substrings). Example:

    $ nimble search math
    linagl:
      url:         https://bitbucket.org/BitPuffin/linagl (hg)
      tags:        library, opengl, math, game
      description: OpenGL math library
      license:     CC0

    extmath:
      url:         git://github.com/achesak/extmath.nim (git)
      tags:        library, math, trigonometry
      description: Nim math library
      license:     MIT

Searches are case insensitive.

An optional ``--ver`` parameter can be specified to tell Nimble to
query remote Git repositories for the list of versions of the packages and
then print the versions. However, please note that this can be slow as each
package must be queried separately.

### nimble path

The nimble ``path`` command will show the absolute path to the installed
packages matching the specified parameters. Since there can be many versions of
the same package installed, the ``path`` command will always show the latest
version. Example:

    $ nimble path argument_parser
    /home/user/.nimble/pkgs/argument_parser-0.1.2

Under Unix you can use backticks to quickly access the directory of a package,
which can be useful to read the bundled documentation. Example:

    $ pwd
    /usr/local/bin
    $ cd `nimble path argument_parser`
    $ less README.md

### nimble init

The nimble ``init`` command will start a simple wizard which will create
a quick ``.nimble`` file for your project in the current directory.

As of version 0.7.0, the ``.nimble`` file that this command creates will
use the new NimScript format.
Check out the [Creating Packages](#creating-packages) section for more info.

### nimble publish

Publishes your Nimble package to the official Nimble package repository.

**Note:** Requires a valid GitHub account with an SSH key attached to it. To upload your public key onto your GitHub account, follow [this link](https://github.com/settings/keys).

### nimble tasks

For a Nimble package in the current working directory, list the tasks which that
package defines. This is only supported for packages utilising the new
nimscript .nimble files.

### nimble dump

Outputs information about the package in the current working directory in
an ini-compatible format. Useful for tools wishing to read metadata about
Nimble packages who do not want to use the NimScript evaluator.

## Configuration

At startup Nimble will attempt to read ``~/.config/nimble/nimble.ini`` on Linux
(on Windows it will attempt to read
``C:\Users\<YourUser>\AppData\Roaming\nimble\nimble.ini``).

The format of this file corresponds to the ini format with some Nim
enhancements. For example:

```ini
nimbleDir = r"C:\Nimble\"

[PackageList]
name = "CustomPackages"
url = "http://mydomain.org/packages.json"

[PackageList]
name = "Local project packages"
path = r"C:\Projects\Nim\packages.json"
```

You can currently configure the following in this file:

* ``nimbleDir`` - The directory which Nimble uses for package installation.
  **Default:** ``~/.nimble/``
* ``chcp`` - Whether to change the current code page when executing Nim
  application packages. If ``true`` this will add ``chcp 65001`` to the
  .cmd stubs generated in ``~/.nimble/bin/``.
  **Default:** ``true``
* ``[PackageList]`` + ``name`` + (``url``|``path``) - You can use this section to specify
  a new custom package list. Multiple package lists can be specified. Nimble
  defaults to the "Official" package list, you can override it by specifying
  a ``[PackageList]`` section named "official". Multiple URLs can be specified
  under each section, Nimble will try each in succession if
  downloading from the first fails. Alternately, ``path`` can specify a
  local file path to copy a package list .json file from.
* ``cloneUsingHttps`` - Whether to replace any ``git://`` inside URLs with
  ``https://``.
  **Default: true**
* ``httpProxy`` - The URL of the proxy to use when downloading package listings.
  Nimble will also attempt to read the ``http_proxy`` and ``https_proxy``
  environment variables.
  **Default: ""**
* ``nimLibPrefix`` - Specifies the Nim standard library prefix to help Nimble
  find the Nim standard library.
  **Default: ""**

## Creating Packages

Nimble works on Git repositories as its primary source of packages. Its list of
packages is stored in a JSON file which is freely accessible in the
[nim-lang/packages repository](https://github.com/nim-lang/packages).
This JSON file provides Nimble with the required Git URL to clone the package
and install it. Installation and build instructions are contained inside a
file with the ``.nimble`` file extension. The Nimble file shares the
package's name, i.e. a package
named "foobar" should have a corresponding ``foobar.nimble`` file.

These files specify information about the package including its author,
license, dependencies and more. Without one, Nimble is not able to install
a package.

A .nimble file can be created easily using Nimble's ``init`` command. This
command will ask you a bunch of questions about your package, then generate a
.nimble file for you in the current directory.

A bare minimum .nimble file follows:

```ini
# Package

version     = "0.1.0"
author      = "Your Name"
description = "Example .nimble file."
license     = "MIT"

# Deps

requires "nim >= 0.10.0"
```

You may omit the dependencies entirely, but specifying the lowest version
of the Nim compiler required is recommended.

You can also specify multiple dependencies like so:

```
# Deps

requires "nim >= 0.10.0", "foobar >= 0.1.0"
requires "fizzbuzz >= 1.0"
```

Nimble currently supports installation of packages from a local directory, a
Git repository and a mercurial repository. The .nimble file must be present in
the root of the directory or repository being installed.

The .nimble file is very flexible because it is interpreted using NimScript.
Because of Nim's flexibility the definitions remain declarative. With the added
ability of using the Nim language to enrich your package specification.
For example, you can define dependencies for specific platforms using Nim's
``when`` statement.

Another great feature
is the ability to define custom Nimble package-specific commands. These are
defined in the .nimble files of course.

```nim
task hello, "This is a hello task":
  echo("Hello World!")
```

You can then execute ``nimble hello``, which will result in the following
output:

```
Executing task hello in /Users/user/projects/pkg/pkg.nimble
Hello World!
```

You can place any Nim code inside these tasks. As long as that code does not
access the FFI. The ``nimscript``
[module](https://nim-lang.org/docs/nimscript.html) in Nim's standard library defines
additional functionality such as the ability to execute external processes
which makes this feature very powerful.

You can also check what tasks are supported by the package in the current
directory by using the ``tasks`` command.

Nimble provides an API which adds even more functionality. For example,
you can specify
pre and post hooks for any Nimble command (including commands that
you define yourself). To do this you can add something like the following:

```nim
before hello:
  echo("About to call hello!")
```

That will result in the following output when ``nimble hello`` is executed (you
must also specify the ``task`` shown above).

```
Executing task hello in /Users/user/projects/pkg/pkg.nimble
About to call hello!
Hello World!
```

Similar to this an ``after`` block is also available for post hooks,
which are executed after Nimble finished executing a command. You can
also return ``false`` from these blocks to stop further execution.

The ``nimscriptapi.nim`` module specifies this and includes other definitions
which are also useful. Take a look at it for more information.

### Project structure

For a package named "foobar", the recommended project structure is the following:

```
.                   # The root directory of the project
├── LICENSE
├── README.md
├── foobar.nimble   # The project .nimble file
└── src
    └── foobar.nim  # Imported via `import foobar`
└── tests           # Contains the tests
    ├── nim.cfg
    ├── tfoo1.nim   # First test
    └── tfoo2.nim   # Second test

```

Note that the .nimble file needs to be in the project's root directory. This
directory structure will be created if you run ``nimble init`` inside a
``foobar`` directory.

**Warning:** When source files are placed in a ``src`` directory, the
.nimble file must contain a ``srcDir = "src"`` directive. The ``nimble init``
command takes care of that for you.

When introducing more modules into your package, you should place them in a
separate directory named ``foobar`` (i.e. your package's name). For example:

```
.                   # The root directory of the project
├── ...
├── foobar.nimble   # The project .nimble file
├── src
│   ├── foobar
│   │   ├── utils.nim   # Imported via `import foobar/utils`
│   │   └── common.nim  # Imported via `import foobar/common`
│   └── foobar.nim      # Imported via `import foobar`
└── ...
```

#### Private modules

You may wish to hide certain modules in your package from the users. Create a
``private`` directory for that purpose. For example:

```
.                   # The root directory of the project
├── ...
├── foobar.nimble   # The project .nimble file
├── src
│   ├── foobar
│   │   ├── private
│   │   │   └── hidden.nim  # Imported via `import foobar/private/hidden`
│   │   ├── utils.nim       # Imported via `import foobar/utils`
│   │   └── common.nim      # Imported via `import foobar/common`
│   └── foobar.nim          # Imported via `import foobar`
└── ...
```

#### Tests

A common problem that arises with tests is the fact that they need to import
the associated package. But the package is in the parent directory. This can
be solved in a few different ways:

* Expect that the package has been installed locally into your
  ``~/.nimble`` directory.
* Use a simple path modification to resolve the package properly.

The latter is highly recommended. Reinstalling the package to test an actively
changing code base is a massive pain.

To modify the path for your tests only, simply add a ``nim.cfg`` file into
your ``tests`` directory with the following contents:

```
--path:"../src/"
```

Nimble offers a pre-defined ``test`` task which compiles and runs all files
in the ``tests`` directory beginning with 't' in their filename.

You may wish to override this ``test`` task in your ``.nimble`` file. This
is particularly useful when you have a single test suite program. Just add
the following to your ``.nimble`` file to override the default ``test`` task.

```nim
task test, "Runs the test suite":
  exec "nim c -r tests/tester"
```

Running ``nimble test`` will now use the ``test`` task you have defined.

### Libraries

Library packages are likely the most popular form of Nimble packages. They are
meant to be used by other library or binary packages.

When Nimble installs a library, it will copy all of its files
into ``$nimbleDir/pkgs/pkgname-ver``. It's up to the package creator to make sure
that the package directory layout is correct, this is so that users of the
package can correctly import the package.

It is suggested that the layout be as follows. The directory layout is
determined by the nature of your package, that is, whether your package exposes
only one module or multiple modules.

If your package exposes only a single module, then that module should be
present in the root directory (the directory with the .nimble file) of your Git
repository, and should be named whatever your package's name is. A good example
of this is the [jester](https://github.com/dom96/jester) package which exposes
the ``jester`` module. In this case the jester package is imported with
``import jester``.

If your package exposes multiple modules then the modules should be in a
``PackageName`` directory. This will allow for a certain measure of isolation
from other packages which expose modules with the same names. In this case
the package's modules will be imported with ``import PackageName/module``.

Here's a simple example multi-module library package called `kool`:

```
.
├── kool
│   ├── useful.nim
│   └── also_useful.nim
└── kool.nimble
```

In regards to modules which you do **not** wish to be exposed. You should place
them in a ``PackageName/private`` directory. Your modules may then import these
private modules with ``import PackageName/private/module``. This directory
structure may be enforced in the future.

All files and folders in the directory of where the .nimble file resides will be
copied as-is, you can however skip some directories or files by setting
the ``skipDirs``, ``skipFiles`` or ``skipExt`` options in your .nimble file.
Directories and files can also be specified on a *whitelist* basis, if you
specify either of ``installDirs``, ``installFiles`` or ``installExt`` then
Nimble will **only** install the files specified.

### Binary packages

These are application packages which require building prior to installation.
A package is automatically a binary package as soon as it sets at least one
``bin`` value, like so:

```ini
bin = @["main"]
```

In this case when ``nimble install`` is invoked, Nimble will build the ``main.nim``
file, copy it into ``$nimbleDir/pkgs/pkgname-ver/`` and subsequently create a
symlink to the binary in ``$nimbleDir/bin/``. On Windows a stub .cmd file is
created instead.

Other files will be copied in the same way as they are for library packages.

Binary packages should not install .nim files so include ``skipExt = @["nim"]``
in your .nimble file, unless you intend for your package to be a binary/library
combo.

Dependencies are automatically installed before building.
It's a good idea to test that the dependencies you specified are correct by
running ``nimble build`` or ``nimble install`` in the directory
of your package.

### Hybrids

One thing to note about binary packages that contain source files aside from
the one(s) specified in `bin` (or that also expose multiple library modules, as
above) is that a binary may share the name of the package: this will mean
that you will not be able to put your additional .nim files in a ``pkgname``
directory. The reason for this is that binaries on some operating systems do
not have an extension, so they will clash with a directory of the same name.

If this is the case, you should place your additional .nim files in a directory
with `pkg` appended after the name of the project. For instance, if you were
building a binary named `project`, you would put any additional source files in
a directory called `projectpkg`. From within project.nim you would then import
those modules namespaced with `projectpkg/`.

### Dependencies

Dependencies are specified using the ``requires`` function. For example:

```
# Dependencies
requires "nim >= 0.10.0", "jester > 0.1 & <= 0.5"
```

Dependency lists support version ranges. These versions may either be a concrete
version like ``0.1``, or they may contain any of the less-than (``<``),
greater-than (``>``), less-than-or-equal-to (``<=``) and greater-than-or-equal-to
(``>=``) operators.
Two version ranges may be combined using the ``&`` operator, for example
``> 0.2 & < 1.0``, which will install a package with the version greater than 0.2
and less than 1.0.

Specifying a concrete version as a dependency is not a good idea because your
package may end up depending on two different versions of the same package.
If this happens, Nimble will refuse to install the package.

In addition to versions you may also specify Git/Mercurial tags, branches and commits.
Although these have to be specific; ranges of commits are not supported.
This is done with the ``#`` character,
for example: ``jester#head``. Which will make your package depend on the
latest commit of Jester.

#### External dependencies

**Warning:** This feature is brand new in Nimble v0.8.0. Breaking changes
related to it are more likely to be introduced than for any other Nimble
features.

Starting with Nimble v0.8.0, you can now specify external dependencies. These
are dependencies which are not managed by Nimble and can only be installed via
your system's package manager or downloaded manually via the internet.

As an example, to specify a dependency on openssl you may put this in your
.nimble file:

```nim
when defined(nimdistros):
  import distros
  if detectOs(Ubuntu):
    foreignDep "libssl-dev"
  else:
    foreignDep "openssl"
```

The ``when`` branch is important to support installation using older versions
of Nimble.

The [distros module](https://nim-lang.org/docs/distros.html) in Nim's
standard library contains a list of all the supported Operating Systems and
Linux distributions.

With this inside your .nimble file, Nimble will output the following after
installing your package (on macOS):

```
  Hint: This package requires some external dependencies.
  Hint: To install them you may be able to run:
  Hint:   brew install openssl
```

### Nim compiler

The Nim compiler cannot read .nimble files. Its knowledge of Nimble is
limited to the ``nimblePath`` feature which allows it to use packages installed
in Nimble's package directory when compiling your software. This means that
it cannot resolve dependencies, and it can only use the latest version of a
package when compiling.

When Nimble builds your package it actually executes the Nim compiler.
It resolves the dependencies and feeds the path of each package to
the compiler so that it knows precisely which version to use.

This means that you can safely compile using the compiler when developing your
software, but you should use Nimble to build the package before publishing it
to ensure that the dependencies you specified are correct.

### Compile with `nim` after changing the nimble directory

The Nim compiler has been preconfigured to look at the default nimble directory while compiling,
so no extra step is required to use nimble managed packages in your code.
However, if you are using a custom `nimbleDir`, you need to specify the
`--nimblePath:PATH` option. For example,
if your `nimble` directory is located at `/some/custom/path/nimble`, this should work:

```
nim c --nimblePath:/some/custom/path/nimble/pkgs main.nim
```

Some code editors rely on `nim check` to check for errors under the hood (e.g. VScode),
and the editor extension may not allow users to pass custom option to `nim check`, which
will cause `nim check` to scream `Error: cannot open file:<the_package>`. In this case,
you will have to use [Nim compiler's configuration files](https://nim-lang.org/docs/nimc.html#compiler-usage-configuration-files). Simply add the line:
```
nimblePath = "/some/custom/path/nimble/pkgs"
```
to the `nim.cfg` located in any directory listed in the [documentation](https://nim-lang.org/docs/nimc.html#compiler-usage-configuration-files), this should resolve the problem.

### Versions

Versions of cloned packages via Git or Mercurial are determined through the
repository's *tags*.

When installing a package which needs to be downloaded, after the download is
complete and if the package is distributed through a VCS, Nimble will check the
cloned repository's tags list. If no tags exist, Nimble will simply install the
HEAD (or tip in Mercurial) of the repository. If tags exist, Nimble will attempt
to look for tags which resemble versions (e.g. v0.1) and will then find the
latest version out of the available tags, once it does so it will install the
package after checking out the latest version.

You can force the installation of the HEAD of the repository by specifying
``#head`` after the package name in your dependency list.

#### Releasing a new version

Version releases are done by creating a tag in your Git or Mercurial
repository.

Whenever you want to release a new version, you should remember to first
increment the version in your ``.nimble`` file and commit your changes. Only
after that is done should you tag the release.

To summarise, the steps for release are:

* Increment the version in your ``.nimble`` file.
* Commit your changes.
* Tag your release, by for example running ``git tag v0.2.0``.
* Push your tags and commits.

Once the new tag is in the remote repository, Nimble will be able to detect
the new version.

## Publishing packages

Publishing packages isn't a requirement. But doing so allows people to associate
a specific name to a URL pointing to your package. This mapping is stored
in an official packages repository located
[here](https://github.com/nim-lang/packages).

This repository contains a ``packages.json`` file which lists all the published
packages. It contains a set of package names with associated metadata. You
can read more about this metadata in the
[readme for the packages repository](https://github.com/nim-lang/packages#readme).

To publish your package you need to fork that repository, and add an entry
into the ``packages.json`` file for your package. Then create a pull request
with your changes. **You only need to do this
once**.

Nimble includes a ``publish`` command which does this for you automatically.

## .nimble reference

### [Package]

#### Required

* ``name`` - The name of the package. *(This is not required in the new NimScript format)*
* ``version`` - The *current* version of this package. This should be incremented
  **before** tagging the current version using ``git tag`` or ``hg tag``.
* ``author`` - The name of the author of this package.
* ``description`` - A string describing the package.
* ``license`` - The name of the license in which this package is licensed under.

#### Optional

* ``skipDirs`` - A list of directory names which should be skipped during
  installation, separated by commas.
* ``skipFiles`` - A list of file names which should be skipped during
  installation, separated by commas.
* ``skipExt`` - A list of file extensions which should be skipped during
  installation, the extensions should be specified without a leading ``.`` and
  should be separated by commas.
* ``installDirs`` - A list of directories which should exclusively be installed,
  if this option is specified nothing else will be installed except the dirs
  listed here, the files listed in ``installFiles``, the files which share the
  extensions listed in ``installExt``, the .nimble file and the binary
  (if ``bin`` is specified). Separated by commas.
* ``installFiles`` - A list of files which should be exclusively installed,
  this complements ``installDirs`` and ``installExt``. Only the files listed
  here, directories listed in ``installDirs``, files which share the extension
  listed in ``installExt``, the .nimble file and the binary (if ``bin`` is
  specified) will be installed. Separated by commas.
* ``installExt`` - A list of file extensions which should be exclusively
  installed, this complements ``installDirs`` and ``installFiles``.
  Separated by commas.
* ``srcDir`` - Specifies the directory which contains the .nim source files.
  **Default**: The directory in which the .nimble file resides; i.e. root dir of
  the package.
* ``binDir`` - Specifies the directory where ``nimble build`` will output
  binaries.
  **Default**: The directory in which the .nimble file resides; i.e.
  root dir of the package.
* ``bin`` - A list of files which should be built separated by commas with
  no file extension required. This option turns your package into a *binary
  package*, Nimble will build the files specified and install them appropriately.
* ``backend`` - Specifies the backend which will be used to build the files
  listed in ``bin``. Possible values include: ``c``, ``cc``, ``cpp``, ``objc``,
  ``js``.
  **Default**: c

### [Deps]/[Dependencies]

#### Optional

* ``requires`` - Specified a list of package names with an optional version
  range separated by commas.
  **Example**: ``nim >= 0.10.0, jester``; with this value your package will
  depend on ``nim`` version 0.10.0 or greater and on any version of ``jester``.

## Nimble's folder structure and packages

Nimble stores everything that has been installed in ``~/.nimble`` on Unix systems
and in your ``$home/.nimble`` on Windows. Libraries are stored in
``$nimbleDir/pkgs``, and binaries are stored in ``$nimbleDir/bin``. Most Nimble
packages will provide ``.nim`` files and some documentation. The Nim
compiler is aware of Nimble and will automatically find the modules so you can
``import modulename`` and have that working without additional setup.

However, some Nimble packages can provide additional tools or commands. If you
don't add their location (``$nimbleDir/bin``) to your ``$PATH`` they will not
work properly and you won't be able to run them.

## Troubleshooting

* ```SSL support is not available. Cannot connect over SSL. [HttpRequestError]```

Make sure that Nimble is configured to run with SSL, adding a ```-d:ssl```
flag to the file ```src/nimble.nim.cfg```.
After that, you can run ```src/nimble install``` and overwrite the existing
installation.

* ``Could not download: error:14077410:SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert handshake failure``

If you are on macOS, you need to set and export the ```DYLD_LIBRARY_PATH``` environment variable to the directory where your OpenSSL libraries are. For example, if you use OpenSSL, you have to set ```export DYLD_LIBRARY_PATH=/usr/local/opt/openssl/lib``` in your ```$HOME/.bashrc``` file.

* ``Error: ambiguous identifier: 'version' --use nimscriptapi.version or system.version``

Make sure that you are running at least version 0.16.0 of Nim (or the latest nightly).

* ``Error: cannot open '/home/user/.nimble/lib/system.nim'.``

Nimble cannot find the Nim standard library. This is considered a bug so
please report it. As a workaround you can set the ``NIM_LIB_PREFIX`` environment
variable to the directory where ``lib/system.nim`` (and other standard library
files) are found. Alternatively you can also configure this in Nimble's
config file.

## Repository information

This repository has two main branches: ``master`` and ``stable``.

The ``master`` branch is...

* default
* bleeding edge
* tested to compile with a pinned (close to HEAD) commit of Nim

The ``stable`` branch is...

* installed by ``koch tools``/``koch nimble``
* relatively stable
* should compile with Nim HEAD as well as the latest Nim version

Note: The travis build only tests whether Nimble works with the latest Nim
version.

A new Nim release (via ``koch xz``) will always bundle the ``stable`` branch.

## Contribution

If you would like to help, feel free to fork and make any additions you see fit
and then send a pull request.

If you have any questions about the project, you can ask me directly on GitHub,
ask on the Nim [forum](https://forum.nim-lang.org), or ask on Freenode in
the #nim channel.

## Implementation details

### .nimble-link

These files are created by Nimble when using the ``develop`` command. They
are very simple and contain two lines.

**The first line:** Always a path to the `.nimble` file.

**The second line:** Always a path to the Nimble package's source code. Usually
``$pkgDir/src``, depending on what ``srcDir`` is set to.

The paths written by Nimble are **always** absolute. But Nimble (and the
Nim compiler) also supports relative paths, which will be read relative to
the `.nimble-link` file.

## About

Nimble has been written by [Dominik Picheta](https://picheta.me/) with help from
a number of
[contributors](https://github.com/nim-lang/nimble/graphs/contributors).
It is licensed under the 3-clause BSD license, see [license.txt](license.txt)
for more information.
