diff --git a/json_logic.gemspec b/json_logic.gemspec
index 0b60e28..d060ba6 100644
--- a/json_logic.gemspec
+++ b/json_logic.gemspec
@@ -20,9 +20,9 @@ Gem::Specification.new do |spec|
 
   spec.required_ruby_version = '>= 2.2'
 
-  spec.add_development_dependency 'bundler',  '~> 2.0.1'
-  spec.add_development_dependency 'rake',     '~> 10.0'
-  spec.add_development_dependency 'minitest', '~> 5.0'
+  spec.add_development_dependency 'bundler',  '>= 2.0.1'
+  spec.add_development_dependency 'rake',     '>= 10.0'
+  spec.add_development_dependency 'minitest', '>= 5.0'
   spec.add_development_dependency 'byebug'
   spec.add_development_dependency 'pry'
   spec.add_runtime_dependency 'backport_dig' if Gem::Version.new(RUBY_VERSION) < Gem::Version.new('2.3')
diff --git a/lib/json_logic.rb b/lib/json_logic.rb
index f7b2e1f..3bb256b 100644
--- a/lib/json_logic.rb
+++ b/lib/json_logic.rb
@@ -5,33 +5,57 @@
 module JSONLogic
   def self.apply(logic, data)
     if logic.is_a?(Array)
-      return logic.map { |val| apply(val, data) }
-    end
-
-    return logic unless logic.is_a?(Hash)                  # pass-thru
+      logic.map do |val|
+        apply(val, data)
+      end
+    elsif !logic.is_a?(Hash)
+      # Pass-thru
+      logic
+    else
+      if data.is_a?(Hash)
+        data = data.stringify_keys
+      end
+      data ||= {}
 
-    data = data.stringify_keys if data.is_a?(Hash)         # Stringify keys to keep out problems with symbol/string mismatch
-    operator, values = logic.first                         # unwrap single-key hash
-    values = [values] unless values.is_a?(Array)           # syntactic sugar
-    Operation.perform(operator, values, data || {})
+      operator, values = operator_and_values_from_logic(logic)
+      Operation.perform(operator, values, data)
+    end
   end
 
+  # Return a list of the non-literal data used. Eg, if the logic contains a {'var' => 'bananas'} operation, the result of
+  # uses_data on this logic will be a collection containing 'bananas'
   def self.uses_data(logic)
     collection = []
 
-    operator, values = logic.first
-    values = [values] unless values.is_a?(Array)
-    if operator == 'var'
-      collection << values[0]
-    else
-      values.each { |val|
-        collection.concat(uses_data(val))
-      }
+    if logic.kind_of?(Hash) || logic.kind_of?(Array) # If we are still dealing with logic, keep going. Else it's a value.
+      operator, values = operator_and_values_from_logic(logic)
+
+      if operator == 'var' # TODO: It may be that non-var operators use data so we may want a flag or collection that indicates data use.
+        if values[0] != JSONLogic::ITERABLE_KEY
+          collection << values[0]
+        end
+      else
+        values.each do |val|
+          collection.concat(uses_data(val))
+        end
+      end
     end
 
     return collection.uniq
   end
 
+  def self.operator_and_values_from_logic(logic)
+    # Unwrap single-key hash
+    operator, values = logic.first
+
+    # Ensure values is an array
+    if !values.is_a?(Array)
+      values = [values]
+    end
+
+    [operator, values]
+  end
+
   def self.filter(logic, data)
     data.select { |d| apply(logic, d) }
   end
diff --git a/lib/json_logic/operation.rb b/lib/json_logic/operation.rb
index db6712d..5cec5b6 100644
--- a/lib/json_logic/operation.rb
+++ b/lib/json_logic/operation.rb
@@ -1,9 +1,22 @@
 module JSONLogic
+  ITERABLE_KEY = "".freeze
+
   class Operation
     LAMBDAS = {
       'var' => ->(v, d) do
-        return d unless d.is_a?(Hash) or d.is_a?(Array)
-        return v == [""] ? (d.is_a?(Array) ? d : d[""]) : d.deep_fetch(*v)
+        if !(d.is_a?(Hash) || d.is_a?(Array))
+          d
+        else
+          if v == [JSONLogic::ITERABLE_KEY]
+            if d.is_a?(Array)
+              d
+            else
+              d[JSONLogic::ITERABLE_KEY]
+            end
+          else
+            d.deep_fetch(*v)
+          end
+        end
       end,
       'missing' => ->(v, d) { v.select { |val| d.deep_fetch(val).nil? } },
       'missing_some' => ->(v, d) {