Change the API to use formal naming instead of operator overloads

spec/std/hash_spec.cr

@@ -105,43 +105,43 @@ describe "Hash" do
     h3 = {"c" => 3}
     h4 = {} of Nil => Nil
 
-    describe "<" do
+    describe "#proper_subset?" do
       it do
-        (h1 < h2).should be_true
-        (h2 < h1).should be_false
-        (h1 < h1).should be_false
-        (h1 < h3).should be_false
-        (h1 < h4).should be_false
+        h1.proper_subset?(h2).should be_true
+        h2.proper_subset?(h1).should be_false
+        h1.proper_subset?(h1).should be_false
+        h1.proper_subset?(h3).should be_false
+        h1.proper_subset?(h4).should be_false
       end
     end
 
-    describe "<=" do
+    describe "#subset?" do
       it do
-        (h1 <= h2).should be_true
-        (h2 <= h1).should be_false
-        (h1 <= h1).should be_true
-        (h1 <= h3).should be_false
-        (h1 <= h4).should be_false
+        h1.subset?(h2).should be_true
+        h2.subset?(h1).should be_false
+        h1.subset?(h1).should be_true
+        h1.subset?(h3).should be_false
+        h1.subset?(h4).should be_false
       end
     end
 
-    describe ">" do
+    describe "#proper_superset?" do
       it do
-        (h1 > h2).should be_false
-        (h2 > h1).should be_true
-        (h1 > h1).should be_false
-        (h1 > h3).should be_false
-        (h1 > h4).should be_true
+        h1.proper_superset?(h2).should be_false
+        h2.proper_superset?(h1).should be_true
+        h1.proper_superset?(h1).should be_false
+        h1.proper_superset?(h3).should be_false
+        h1.proper_superset?(h4).should be_true
       end
     end
 
-    describe ">=" do
+    describe "#superset?" do
       it do
-        (h1 >= h2).should be_false
-        (h2 >= h1).should be_true
-        (h1 >= h1).should be_true
-        (h1 >= h3).should be_false
-        (h1 >= h4).should be_true
+        h1.superset?(h2).should be_false
+        h2.superset?(h1).should be_true
+        h1.superset?(h1).should be_true
+        h1.superset?(h3).should be_false
+        h1.superset?(h4).should be_true
       end
     end
   end

src/hash.cr

@@ -1748,27 +1748,25 @@ class Hash(K, V)
   end
 
   # Returns `true` if `self` is a subset of *other*.
-  def <(other : Hash)
-    return false if size >= other.size
-    self <= other
+  def proper_subset?(other : Hash)
+    return false if other.size <= size
+    all? { |key, value| other[key]? == value }
   end
 
   # Returns `true` if `self` is a subset of *other* or equals to *other*.
-  def <=(other : Hash)
-    return false if size > other.size
-    all? do |key, value|
-      other[key]? == value
-    end
+  def subset?(other : Hash)
+    return false if other.size < size
+    all? { |key, value| other[key]? == value }
   end
 
   # Returns `true` if *other* is a subset of `self`.
-  def >(other : Hash)
-    other < self
+  def superset?(other : Hash)
+    other.subset?(self)
   end
 
   # Returns `true` if *other* is a subset of `self` or equals to `self`.
-  def >=(other : Hash)
-    other <= self
+  def proper_superset?(other : Hash)
+    other.proper_subset?(self)
   end
 
   # See `Object#hash(hasher)`