Stupidly I figured Ruby did this for us, but why would it?

Using the example from the existing code:

  CHECKSUM_TYPES.each do |type|
    if !instance_variable_defined?("@#{type}")
      class_value = self.class.send(type)
      instance_variable_set("@#{type}", class_value) if class_value
    end
  end

I extracted that block into a method 'set_instance_variable' which I
then used in all places where this behavior was being used.

You can now use "url", "version", "homepage", and any checksums as
class methods, like so:

    class Dos2unix <Formula
      url 'http://www.sfr-fresh.com/linux/misc/old/dos2unix-3.1.tar.gz'
      md5 '25ff56bab202de63ea6f6c211c416e96'
      homepage 'http://www.sfr-fresh.com/linux/misc/'
    end

The previous usage ("@url = 'http://example.com/tarball.tgz'") still
works, maintaining compatibility with previous formulas.

"dos2unix.rb" is translated into the new format as an example.

I used the same option flag as ruby gems does.

The code also makes sure to terminate with a newline, unless the
output is empty.

Using more Pathname methods.

Only show text if verbose mode is on, as is typical for the rest of our install output.

TODO: would be nice if we knew you were a dev and automatically enabled verbose mode perhaps.

Allow Formula.skip_clean? to prevent empty folders from being removed
as part of the brewing cleanup process.

Corrected README path.

Ohai is for titles, to separate sections of output so it is more readable, it
truncates long lines for this purpose. So don't use it if the line you are
outputting is likely to be long and important. Instead prefix that line with
a summary header.

Eg gettext gets added into LDFLAGS, INCLUDE and that. I hope I got everything
that is typical. Prolly not. But we'll find out.

Made readline keg_only because the BSD version is provided by OS X, and I
don't want bug reports that are tricky to solve due to unexpected differences
between the two.

Conflicts:
	Library/Formula/imagemagick.rb
	Library/Formula/taglib.rb
	Library/Homebrew/brew.h.rb
	Library/Homebrew/formula.rb
	bin/brew

Is it a DSL? No. But people call it that apparently.

To add a dependency:

class Doe <Formula
  depends_on 'ray'
  depends_on 'mee' => :optional
  depends_on 'far' => :recommended
  depends_on Sew.new
end

Sew would be a formula you have defined in this Formula file. This is useful,
eg. see Python's formula. Formula specified in this fashion cannot be linked
into the HOMEBREW_PREFIX, they are considered private libraries. This allows
you to create custom installations that are very specific to your formula.

More features to come, like specifying versions

I left update_from_masterbrew! as a historical reference.

Don't symlink, as multiple formula will install to this directory.

GNU GetText breaks eg. Ruby 1.9 builds, and some other formula I have been building too. But it is required by eg. glib. So to solve this we are going to by default not symlink gettext into the Homebrew prefix.

Formula that depend on GetText will have the gettext paths added to the brewing environment automatically. Neat.

The "brew gen" command doesn't seem to exist, changed to "brew create", which isn't otherwise mentioned

Don't delete it if it doesn't exist.

This way caveats and other warnings/errors don't appear connected to the Summary text.

Eg. sbin may be part of the formula, but that isn't in the default Mac PATH. Also will avoid bug reports for users who forget to amend their PATH and stick Homebrew somewhere different.

I didn't change the class name, it's clear from the context where it is used what it does. However when just looking at files to figure out the nature of Homebrew I believe in clear naming.

Otherwise funny names earn you points.

Having gone through our patches it's clear that p1 is more standard.

Also fixed a bug where returning DATA outside of an array would fail to patch.