From bf5f83ffdafc1aa23c49f8bc28db18923df7c784 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Sat, 14 Nov 2015 17:05:57 +0900
Subject: Add comparison methods to Hash

---
 mrblib/hash.rb | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 test/t/hash.rb | 72 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 168 insertions(+)

diff --git a/mrblib/hash.rb b/mrblib/hash.rb
index e3e709070..8e56fca81 100644
--- a/mrblib/hash.rb
+++ b/mrblib/hash.rb
@@ -346,6 +346,102 @@ class Hash
     h.each_key{|k| self[k] = h[k]}
     self
   end
+
+  ##
+  #  call-seq:
+  #    hash < other -> true or false
+  #
+  #  Returns <code>true</code> if <i>hash</i> is subset of
+  #  <i>other</i>.
+  #
+  #     h1 = {a:1, b:2}
+  #     h2 = {a:1, b:2, c:3}
+  #     h1 < h2    #=> true
+  #     h2 < h1    #=> false
+  #     h1 < h1    #=> false
+  #
+  def <(hash)
+    begin
+      hash = hash.to_hash
+    rescue NoMethodError
+      raise TypeError, "can't convert #{hash.class} to Hash"
+    end
+    size < hash.size and all? {|key, val|
+      hash.key?(key) and hash[key] == val
+    }
+  end
+
+  ##
+  #  call-seq:
+  #    hash <= other -> true or false
+  #
+  #  Returns <code>true</code> if <i>hash</i> is subset of
+  #  <i>other</i> or equals to <i>other</i>.
+  #
+  #     h1 = {a:1, b:2}
+  #     h2 = {a:1, b:2, c:3}
+  #     h1 <= h2   #=> true
+  #     h2 <= h1   #=> false
+  #     h1 <= h1   #=> true
+  #
+  def <=(hash)
+    begin
+      hash = hash.to_hash
+    rescue NoMethodError
+      raise TypeError, "can't convert #{hash.class} to Hash"
+    end
+    size <= hash.size and all? {|key, val|
+      hash.key?(key) and hash[key] == val
+    }
+  end
+
+  ##
+  #  call-seq:
+  #    hash > other -> true or false
+  #
+  #  Returns <code>true</code> if <i>other</i> is subset of
+  #  <i>hash</i>.
+  #
+  #     h1 = {a:1, b:2}
+  #     h2 = {a:1, b:2, c:3}
+  #     h1 > h2    #=> false
+  #     h2 > h1    #=> true
+  #     h1 > h1    #=> false
+  #
+  def >(hash)
+    begin
+      hash = hash.to_hash
+    rescue NoMethodError
+      raise TypeError, "can't convert #{hash.class} to Hash"
+    end
+    size > hash.size and hash.all? {|key, val|
+      key?(key) and self[key] == val
+    }
+  end
+
+  ##
+  #  call-seq:
+  #    hash >= other -> true or false
+  #
+  #  Returns <code>true</code> if <i>other</i> is subset of
+  #  <i>hash</i> or equals to <i>hash</i>.
+  #
+  #     h1 = {a:1, b:2}
+  #     h2 = {a:1, b:2, c:3}
+  #     h1 >= h2   #=> false
+  #     h2 >= h1   #=> true
+  #     h1 >= h1   #=> true
+  #
+  def >=(hash)
+    begin
+      hash = hash.to_hash
+    rescue NoMethodError
+      raise TypeError, "can't convert #{hash.class} to Hash"
+    end
+    size >= hash.size and hash.all? {|key, val|
+      key?(key) and self[key] == val
+    }
+  end
 end
 
 ##
diff --git a/test/t/hash.rb b/test/t/hash.rb
index 3196cc97a..8ef3d9c10 100644
--- a/test/t/hash.rb
+++ b/test/t/hash.rb
@@ -351,3 +351,75 @@ assert('Hash#rehash') do
   h.rehash
   assert_equal("b", h[[:b]])
 end
+
+assert('Hash#<') do
+  h1 = {a:1, b:2}
+  h2 = {a:1, b:2, c:3}
+
+  assert_false(h1 < h1)
+  assert_true(h1 < h2)
+  assert_false(h2 < h1)
+  assert_false(h2 < h2)
+
+  h1 = {a:1}
+  h2 = {a:2}
+
+  assert_false(h1 < h1)
+  assert_false(h1 < h2)
+  assert_false(h2 < h1)
+  assert_false(h2 < h2)
+end
+
+assert('Hash#<=') do
+  h1 = {a:1, b:2}
+  h2 = {a:1, b:2, c:3}
+
+  assert_true(h1 <= h1)
+  assert_true(h1 <= h2)
+  assert_false(h2 <= h1)
+  assert_true(h2 <= h2)
+
+  h1 = {a:1}
+  h2 = {a:2}
+
+  assert_true(h1 <= h1)
+  assert_false(h1 <= h2)
+  assert_false(h2 <= h1)
+  assert_true(h2 <= h2)
+end
+
+assert('Hash#>=') do
+  h1 = {a:1, b:2}
+  h2 = {a:1, b:2, c:3}
+
+  assert_true(h1 >= h1)
+  assert_false(h1 >= h2)
+  assert_true(h2 >= h1)
+  assert_true(h2 >= h2)
+
+  h1 = {a:1}
+  h2 = {a:2}
+
+  assert_true(h1 >= h1)
+  assert_false(h1 >= h2)
+  assert_false(h2 >= h1)
+  assert_true(h2 >= h2)
+end
+
+assert('Hash#>') do
+  h1 = {a:1, b:2}
+  h2 = {a:1, b:2, c:3}
+
+  assert_false(h1 > h1)
+  assert_false(h1 > h2)
+  assert_true(h2 > h1)
+  assert_false(h2 > h2)
+
+  h1 = {a:1}
+  h2 = {a:2}
+
+  assert_false(h1 > h1)
+  assert_false(h1 > h2)
+  assert_false(h2 > h1)
+  assert_false(h2 > h2)
+end
-- 
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