Add NamedTuple#has_key?(key : String) overload

Sija · Ary Borenszweig · commit 819b104b2e26 · 2017-01-04T15:46:02.000+02:00
See #3824
diff --git a/spec/std/named_tuple_spec.cr b/spec/std/named_tuple_spec.cr
@@ -207,13 +207,20 @@ describe "NamedTuple" do
     i.should eq(2)
   end
 
-  it "does has_key?" do
+  it "does has_key? with symbol" do
     tup = {a: 1, b: 'a'}
     tup.has_key?(:a).should be_true
     tup.has_key?(:b).should be_true
     tup.has_key?(:c).should be_false
   end
 
+  it "does has_key? with string" do
+    tup = {a: 1, b: 'a'}
+    tup.has_key?("a").should be_true
+    tup.has_key?("b").should be_true
+    tup.has_key?("c").should be_false
+  end
+
   it "does empty" do
     {a: 1}.empty?.should be_false
   end
diff --git a/src/named_tuple.cr b/src/named_tuple.cr
@@ -219,6 +219,14 @@ struct NamedTuple
     false
   end
 
+  # ditto
+  def has_key?(key : String) : Bool
+    {% for key in T %}
+      return true if {{key.stringify}} == key
+    {% end %}
+    false
+  end
+
   # Appends a string representation of this named tuple to the given `IO`.
   #
   # ```
