complex.c: implement `Complex` addition and subtraction in C.

mrbgems/mruby-complex/mrblib/complex.rb

@@ -19,22 +19,6 @@ class Complex < Numeric
     Complex(-real, -imaginary)
   end
 
-  def +(rhs)
-    if rhs.is_a? Complex
-      Complex(real + rhs.real, imaginary + rhs.imaginary)
-    elsif rhs.is_a? Numeric
-      Complex(real + rhs, imaginary)
-    end
-  end
-
-  def -(rhs)
-    if rhs.is_a? Complex
-      Complex(real - rhs.real, imaginary - rhs.imaginary)
-    elsif rhs.is_a? Numeric
-      Complex(real - rhs, imaginary)
-    end
-  end
-
   def abs
     Math.hypot imaginary, real
   end

mrbgems/mruby-complex/src/complex.c

@@ -171,6 +171,48 @@ complex_eq(mrb_state *mrb, mrb_value x)
   return mrb_bool_value(mrb_complex_eq(mrb, x, y));
 }
 
+static mrb_value
+complex_add(mrb_state *mrb, mrb_value x)
+{
+  mrb_value y = mrb_get_arg1(mrb);
+  struct mrb_complex *p1 = complex_ptr(mrb, x);
+
+  switch (mrb_type(y)) {
+  case MRB_TT_COMPLEX:
+    {
+      struct mrb_complex *p2 = complex_ptr(mrb, y);
+      return mrb_complex_new(mrb, p1->real+p2->real, p1->imaginary+p2->imaginary);
+    }
+
+  default:
+    {
+      mrb_float z = mrb_to_flo(mrb, y);
+      return mrb_complex_new(mrb, p1->real+z, p1->imaginary);
+    }
+  }
+}
+
+static mrb_value
+complex_sub(mrb_state *mrb, mrb_value x)
+{
+  mrb_value y = mrb_get_arg1(mrb);
+  struct mrb_complex *p1 = complex_ptr(mrb, x);
+
+  switch (mrb_type(y)) {
+  case MRB_TT_COMPLEX:
+    {
+      struct mrb_complex *p2 = complex_ptr(mrb, y);
+      return mrb_complex_new(mrb, p1->real-p2->real, p1->imaginary-p2->imaginary);
+    }
+
+  default:
+    {
+      mrb_float z = mrb_to_flo(mrb, y);
+      return mrb_complex_new(mrb, p1->real-z, p1->imaginary);
+    }
+  }
+}
+
 static mrb_value
 complex_mul(mrb_state *mrb, mrb_value x)
 {
@@ -386,6 +428,8 @@ void mrb_mruby_complex_gem_init(mrb_state *mrb)
   mrb_define_method(mrb, comp, "to_f", complex_to_f, MRB_ARGS_NONE());
   mrb_define_method(mrb, comp, "to_i", complex_to_i, MRB_ARGS_NONE());
   mrb_define_method(mrb, comp, "to_c", complex_to_c, MRB_ARGS_NONE());
+  mrb_define_method(mrb, comp, "+", complex_add, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, comp, "-", complex_sub, MRB_ARGS_REQ(1));
   mrb_define_method(mrb, comp, "*", complex_mul, MRB_ARGS_REQ(1));
   mrb_define_method(mrb, comp, "/", complex_div, MRB_ARGS_REQ(1));
   mrb_define_method(mrb, comp, "quo", complex_div, MRB_ARGS_REQ(1));