Support a Complex in Kernel.BigDecimal()

Author: mrkn

ext/bigdecimal/bigdecimal.c

@@ -2631,6 +2631,7 @@ VpNewVarArg(int argc, VALUE *argv)
         }
     }
 
+  retry:
     switch (TYPE(iniValue)) {
       case T_DATA:
 	if (is_kind_of_BigDecimal(iniValue)) {
@@ -2668,6 +2669,18 @@ VpNewVarArg(int argc, VALUE *argv)
 	}
 	return GetVpValueWithPrec(iniValue, mf, 1);
 
+      case T_COMPLEX:
+        {
+            VALUE im;
+            im = rb_complex_imag(iniValue);
+            if (!is_zero(im)) {
+                rb_raise(rb_eArgError,
+                         "Unable to make a BigDecimal from non-zero imaginary number");
+            }
+            iniValue = rb_complex_real(iniValue);
+            goto retry;
+        }
+
       case T_STRING:
 	/* fall through */
       default:

test/bigdecimal/test_bigdecimal.rb

@@ -137,6 +137,14 @@ def test_BigDecimal_with_float
     end
   end
 
+  def test_BigDecimal_with_complex
+    assert_equal(BigDecimal("1"), BigDecimal(Complex(1, 0)))
+    assert_equal(BigDecimal("0.333333333333333333333"), BigDecimal(Complex(1.quo(3), 0), 21))
+    assert_equal(BigDecimal("0.1235"), BigDecimal(Complex(0.1234567, 0), 4))
+
+    assert_raise_with_message(ArgumentError, "Unable to make a BigDecimal from non-zero imaginary number") { BigDecimal(Complex(1, 1)) }
+  end
+
   def test_BigDecimal_with_big_decimal
     assert_equal(BigDecimal(1), BigDecimal(BigDecimal(1)))
     assert_equal(BigDecimal('+0'), BigDecimal(BigDecimal('+0')))