From d366b28923ed31aafe914a3f27873b2b7605e903 Mon Sep 17 00:00:00 2001
From: Max Howell
Date: Mon, 7 Sep 2009 01:06:08 +0100
Subject: Dependency resolution

Specify dependencies in your formula's deps function. You can return an Array,
String or Hash, eg:

    def deps
      { :optional => 'libogg', :required => %w[flac sdl], :recommended => 'cmake' }
    end

Note currently the Hash is flattened and qualifications are ignored. If you
only return an Array or String, the qualification is assumed to be :required.

Other packaging systems have problems when it comes to packages requiring a
specific version of a package, or some patches that may not work well with
other software. With Homebrew we have some options:

1.  If the formula is vanilla but an older version we can cherry-pick the old
    version and install it in the Cellar in parallel, but just not symlink it
    into /usr/local while forcing the formula that depends on it to link to
    that one and not any other versions of it.
2.  If the dependency requires patches then we shouldn't install this for use
    by any other tools, (I guess this needs to be decided on a per-situation
    basis). It can be installed into the parent formula's prefix, and not
    symlinked into /usr/local. In this case the dependency's Formula
    derivation should be saved in the parent formula's file (check git or
    flac for an example of this).

Both the above can be done currently with hacks, so I'll flesh out a proper
way sometime this week.
---
 Library/Formula/mysql.rb | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'Library/Formula/mysql.rb')

diff --git a/Library/Formula/mysql.rb b/Library/Formula/mysql.rb
index 662d8320d..5cfb8be41 100644
--- a/Library/Formula/mysql.rb
+++ b/Library/Formula/mysql.rb
@@ -6,8 +6,7 @@ class Mysql <Formula
   @md5='7564d7759a8077b3a0e6190955422287'
 
   def deps
-    # --without-readline means use system's readline
-    LibraryDep.new 'readline'
+    'readline'
   end
 
   def options
-- 
cgit v1.2.3


From 68108e109839a901313b9933cbb1e3202aed90cf Mon Sep 17 00:00:00 2001
From: Max Howell
Date: Fri, 18 Sep 2009 19:16:39 +0100
Subject: Dependency resolution with fancy syntax

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
---
 Library/Formula/mysql.rb | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

(limited to 'Library/Formula/mysql.rb')

diff --git a/Library/Formula/mysql.rb b/Library/Formula/mysql.rb
index 5cfb8be41..76fd2a7c4 100644
--- a/Library/Formula/mysql.rb
+++ b/Library/Formula/mysql.rb
@@ -5,9 +5,7 @@ class Mysql <Formula
   @homepage='http://dev.mysql.com/doc/refman/5.1/en/'
   @md5='7564d7759a8077b3a0e6190955422287'
 
-  def deps
-    'readline'
-  end
+  depends_on 'readline'
 
   def options
     [
-- 
cgit v1.2.3