From bbfb6400c77aeaaf88216263d86491d85a40f8a9 Mon Sep 17 00:00:00 2001
From: Misty De Meo
Date: Tue, 2 Oct 2012 13:21:00 -0500
Subject: Manage Requirements using ComparableSet

ComparableSet only allows a single object of a given class,
choosing the object with the greatest value. This was mainly created
for Requirements, so that, e.g., two X11Dependencies of differing
strictness don't both end up in the same requirement set.

Fixes Homebrew/homebrew#15240.---
 Library/Homebrew/extend/set.rb | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 Library/Homebrew/extend/set.rb

(limited to 'Library/Homebrew/extend')

diff --git a/Library/Homebrew/extend/set.rb b/Library/Homebrew/extend/set.rb
new file mode 100644
index 000000000..b45b85de9
--- /dev/null
+++ b/Library/Homebrew/extend/set.rb
@@ -0,0 +1,24 @@
+require 'set'
+
+class ComparableSet < Set
+  def add new
+    # smileys only
+    return super new unless new.respond_to? :>
+
+    objs = find_all { |o| o.class == new.class }
+    objs.each do |o|
+      return self if o > new
+      delete o
+    end
+    super new
+  end
+
+  alias_method :<<, :add
+
+  # Set#merge bypasses enumerating the set's contents,
+  # so the subclassed #add would never be called
+  def merge enum
+    enum.is_a?(Enumerable) or raise ArgumentError, "value must be enumerable"
+    enum.each { |o| add(o) }
+  end
+end
-- 
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