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Updated developers docs.

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Dominik Picheta 2014-06-24 00:15:26 +01:00
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@ -5,9 +5,42 @@ This file contains information mostly meant for developers willing to produce
[nimrod-code/packages repository](https://github.com/nimrod-code/packages). End
user documentation is provided in the [readme.markdown file](readme.markdown).
## Libraries
## Packages
When babel installs a library it will copy all the files that it downloaded
A Babel package is defined by an ini-like formatted file with the ``.babel``
extension (this document uses the term ".babel file" to refer to them). The
.babel file should be named after the package it describes, i.e. a package
named "foobar" should have a corresponding ``foobar.babel`` file.
These files specify information about the package including its name, author,
license, dependencies and more. Without one Babel is not able to install
a package. A bare minimum .babel file follows:
```ini
[Package]
name = "ProjectName"
version = "0.1.0"
author = "Your Name"
description = "Example .babel file."
license = "MIT"
[Deps]
Requires: "nimrod >= 0.9.2"
```
You may omit the dependencies entirely, but specifying the lowest version
of the Nimrod compiler required is recommended.
Babel currently supports installation of packages from a local directory, a
git repository and a mercurial repository. The .babel file must be present in
the root of the directory or repository being installed.
### Libraries
Library packages are likely the most popular form of Babel packages. They are
meant to be used by other library packages or the ultimate binary packages.
When babel installs a library it will copy all the files in the package
into ``$babelDir/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.
@ -17,7 +50,7 @@ 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 babel file) of your git
present in the root directory (the directory with the .babel file) of your git
repository, it is recommended that in this case you name that module whatever
your package's name is. A good example of this is the
[jester](https://github.com/dom96/jester) package which exposes the ``jester``
@ -40,34 +73,9 @@ copied as-is, you can however skip some directories or files by setting
the ``SkipDirs``, ``SkipFiles`` or ``SkipExt`` options in your .babel file.
Directories and files can also be specified on a *whitelist* basis, if you
specify either of ``InstallDirs``, ``InstallFiles`` or ``InstallExt`` then
babel will **only** install the files specified.
Babel will **only** install the files specified.
### Example library .babel file
```ini
[Package]
name = "ProjectName"
version = "0.1.0"
author = "Your Name"
description = "Example .babel file."
license = "MIT"
SkipDirs = "SomeDir" ; ./SomeDir will not be installed
SkipFiles = "file.txt,file2.txt" ; ./{file.txt, file2.txt} will not be installed
SkipFiles = """
foo.txt
foo2.rst
foo3.md
""" ; Listing the files on multiple lines also works.
[Deps]
Requires: "nimrod >= 0.9.2"
```
All the fields (except ``SkipDirs`` and ``SkipFiles``) under ``[Package]`` are
required. ``[Deps]`` may be omitted.
## Binary packages
### 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
@ -88,9 +96,12 @@ Binary packages should not install .nim files so you should include
``SkipExt = "nim"`` in your .babel file, unless you intend for your package to
be a binary/library combo which is fine.
Dependencies are automatically installed before building.
Dependencies are automatically installed before building. Before publishing your
package you should ensure that the dependencies you specified are correct.
You can do this by running ``babel build`` or ``babel install`` in the directory
of your package.
## Hybrids
### Hybrids
One thing to note about library and binary package hybrids is that your binary
will most likely share the name of the package. This will mean that you will
@ -98,10 +109,10 @@ not be able to put your .nim files in a ``pkgname`` directory. The current
convention to get around this problem is to append ``pkg`` to the name as is
done for babel.
# Dependencies
## Dependencies
Dependencies are specified under the ``[Deps]`` section in a babel file.
The ``requires`` key is used to specify them. For example:
The ``requires`` key field is used to specify them. For example:
```ini
[Deps]
@ -115,7 +126,33 @@ greater-than (``>``), less-than-or-equal-to (``<=``) and greater-than-or-equal-t
``> 0.2 & < 1.0`` which will install a package with the version greater than 0.2
and less than 1.0.
# Versions
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 Babel will refuse to install the package. Similarly you should
not specify an upper-bound as this can lead to a similar issue.
In addition to versions you may also specify git/hg tags, branches and commits.
These have to be concrete however. This is done with the ``#`` character,
for example: ``jester#head``. Which will make your package depend on the
latest commit of Jester.
### Nimrod compiler
The Nimrod compiler cannot read .babel files. Its knowledge of Babel is
limited to the ``babelPaths`` feature which allows it to use packages installed
in Babel'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 Babel builds your package it actually executes the Nimrod 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 babel to build the package before publishing it
to ensure that the dependencies you specified are correct.
## Versions
Versions of cloned packages via git or mercurial are determined through the
repository's *tags*.
@ -128,6 +165,15 @@ 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.
# Submitting your package to the package list.
Babel's packages list is stored on github and everyone is encouraged to add
their own packages to it! Take a look at
[nimrod-code/packages](https://github.com/nimrod-code/packages) to learn more.
# .babel reference
## [Package]
@ -182,9 +228,3 @@ package after checking out the latest version.
range separated by commas.
**Example**: ``nimrod >= 0.9.2, jester``; with this value your package will
depend on ``nimrod`` version 0.9.2 or greater and on any version of ``jester``.
# Submitting your package to the package list.
Babel's packages list is stored on github and everyone is encouraged to add
their own packages to it! Take a look at
[nimrod-code/packages](https://github.com/nimrod-code/packages) to learn more.