Allow convert nil to NaN in Numo::DFloat.cast

Author: mrkn

ext/numo/narray/numo/types/float_macro.h

@@ -12,7 +12,7 @@ extern double pow(double, double);
 #define m_zero 0.0
 #define m_one  1.0
 
-#define m_num_to_data(x) NUM2DBL(x)
+#define m_num_to_data(x) (NIL_P(x) ? nan("") : NUM2DBL(x))
 #define m_data_to_num(x) rb_float_new(x)
 
 #define m_from_double(x) (x)

test/narray_test.rb

@@ -644,4 +644,8 @@ class NArrayTest < Test::Unit::TestCase
     assert { $stderr.string == '' } # no warning message
     $stderr = STDERR
   end
+
+  test "Numo::DFloat.cast(Numo::RObject[1, nil, 3])" do
+    assert { Numo::DFloat[1, Float::NAN, 3] == Numo::DFloat.cast(Numo::RObject[1, nil, 3]) }
+  end
 end