ABOUT

A small unit based buildsystem built on top of bam (http://matricks.github.com/bam/).
I wrote this buildsystem because of problems of duplicated code between by small hobby
projects, and while it solves this problem for me, it might not suit everybody. Feel
free to integrate ideas into your own system, bam based or not.

    BAM INTRO

Bam is at its core a graph walker. Nodes are added by calling AddJob(outfile, info_txt,
command) and then linked together by AddDependency(outfile, infile). Bam then provides
some utilities on top of this, like Compile, Link, Library and automatic depchecking
for C, C++ and Objective-C. When ececuted, bam will check for bam.lua in the current
directory and then execute.

    UNITS

I have decided to split my code into units. A unit is, for me, a self contained library
and/or executable. This buildsystem handles units as a directory containing a file
called build.lua. If This file is present the file will be included and the unit will
be added to the unit list.

A unit is a lua table with function that can be overriden. By default, the functions will
look for C, C++ and Obj-C files in <unitdir>/src and include files in <unitdir>/include
and build a static library. This can be changed by overriding the functions Unit.Init and
Unit.Build. Patching can also be overridden by replacing Unit.Patch and Unit.PatchHeaders

A unit can also depend on other units, usually by calling Unit:Using(depname), which will
in turn make the unit named by depname patch the settings passed to the depending unit.

    CONFIGS AND TARGETS

A config/target combination tells the build system how to build the units. Please see
files in configs/*.lua and targets/*.lua on examples for how this can be done.

The default behaviour is to build all targets for all configs. This can be changed by
adding "<targetname>", "<configname>" or "<targetname>_<configname>" without quotes on
the commandline.

    BUILD STEPS

The system consists of a series of build steps performed in order. A base set of these
are added in the "steps/" directory and can be seen as an example on how to ad new
passes. You could for example do a step that goes through all units and build unit
tests for everything in each units "test/" directory, and add execution of them as
build targets.

Built in steps are:
 * Init      - Sets up base unit state
 * Patch     - Manages unit dependency and loading, as well as setting up settings for
               dependencies
 * Add tools - Allows units to declare new compilers to be used dutring the run.
 * Build     - Builds all imported units per target (BuildTarget) and per target/config
               combo (Build)

    USING THIS BUILDSYSTEM

Copy the build, config and target directories and bam.lua to your project folder, and
modify them after need. By default the system will look for units in "units" and
"externals".

    KNOWN BUGS

Circular unit dependencies are NOT supported.