rebar/README.md
2011-01-17 12:03:30 +01:00

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rebar
=====
rebar is an Erlang build tool that makes it easy to compile and
test Erlang applications, port drivers and releases.
rebar is a self-contained Erlang script, so it's easy to distribute or even
embed directly in a project. Where possible, rebar uses standard Erlang/OTP
conventions for project structures, thus minimizing the amount of build
configuration work. rebar also provides dependency management, enabling
application writers to easily re-use common libraries from a variety of
locations (git, hg, etc).
Building
--------
Information on building and installing Erlang/OTP can be found
in the `INSTALL.md` document.
### Dependencies
To build rebar you will need a working installation of Erlang R13B03 (or
later).
Should you want to clone the rebar repository, you will also require git.
#### Downloading
Clone the git repository:
$ git clone git://github.com/basho/rebar.git
#### Building rebar
$ cd rebar/
$ ./bootstrap
Recompile: src/getopt
...
Recompile: src/rebar_utils
==> rebar (compile)
Congratulations! You now have a self-contained script called "rebar" in
your current working directory. Place this script anywhere in your path
and you can use rebar to build OTP-compliant apps.
Contributing to rebar
=====================
Coding style
------------
Do not introduce trailing whitespace.
Do not introduce lines longer than 80 characters.
### Indentation
To have consistent indentation we have vi modeline/emacs local variable
headers in rebar's source files. This works automatically with vi.
With Emacs you have to declare <code>'erlang-indent-level</code>
set to <code>4</code>
as a safe local variable value. If not configured Emacs will prompt
you to save this as part of custom-set-variables:
'(safe-local-variable-values (quote ((erlang-indent-level . 4))))
You can also tell Emacs to ignore file variables:
(setq enable-local-variables nil
enable-local-eval nil)
Writing Commit Messages
-----------------------
Structure your commit message like this:
<pre>
One line summary (less than 50 characters)
Longer description (wrap at 72 characters)
</pre>
### Summary
* Less than 50 characters
* What was changed
* Imperative present tense (fix, add, change)
> Fix bug 123
> Add 'foobar' command
> Change default timeout to 123
* No period
### Description
* Wrap at 72 characters
* Why, explain intention and implementation approach
* Present tense
### Atomicity
* Break up logical changes
* Make whitespace changes separately
Dialyzer and Tidier
-------------------
Before you submit a patch check for discrepancies with
[Dialyzer](http://www.erlang.org/doc/man/dialyzer.html):
<pre>
$ cd rebar/
$ ./bootstrap debug
$ dialyzer ebin -Wunmatched_returns -Werror_handling -Wrace_conditions -Wunderspecs
</pre>
The following discrepancies are known and safe to ignore:
<pre>
rebar_templater.erl:249: The call rebar_templater:consult(
Cont1::erl_scan:return_cont(),'eof',
Acc::[any()])
contains an opaque term as 1st argument when terms
of different types are expected in these positions
rebar_utils.erl:144: Call to missing or unexported function escript:foldl/3
rebar_utils.erl:165: The created fun has no local return
</pre>
It is **strongly recommended** to check the code with
[Tidier](http://tidier.softlab.ntua.gr:20000/tidier/getstarted).
Select all transformation options and enable **automatic**
transformation.
If Tidier suggests a transformation apply the changes **manually**
to the source code.
Do not use the code from the tarball (*out.tgz*) as it will have
white-space changes
applied by Erlang's pretty-printer.