[ruby/date] Promote simple date to complex date to load fractional date (Fixes #20)

https://github.com/ruby/date/commit/e022e8b3ce

ext/date/date_core.c

@@ -7202,11 +7202,14 @@ d_lite_marshal_load(VALUE self, VALUE a)
 
     if (simple_dat_p(dat)) {
 	if (df || !f_zero_p(sf) || of) {
-	    rb_raise(rb_eArgError,
-		     "cannot load complex into simple");
+	    /* loading a fractional date; promote to complex */
+	    dat = ruby_xrealloc(dat, sizeof(struct ComplexDateData));
+	    RTYPEDDATA(self)->data = dat;
+	    goto complex_data;
 	}
 	set_to_simple(self, &dat->s, nth, jd, sg, 0, 0, 0, HAVE_JD);
     } else {
+      complex_data:
 	set_to_complex(self, &dat->c, nth, jd, df, sf, of, sg,
 		       0, 0, 0, 0, 0, 0,
 		       HAVE_JD | HAVE_DF);
@@ -9318,7 +9321,7 @@ Init_date_core(void)
      */
     rb_define_const(cDate, "GREGORIAN", DBL2NUM(GREGORIAN));
 
-    rb_define_alloc_func(cDate, d_lite_s_alloc_complex);
+    rb_define_alloc_func(cDate, d_lite_s_alloc_simple);
 
 #ifndef NDEBUG
     rb_define_private_method(CLASS_OF(cDate), "_valid_jd?",
@@ -9368,7 +9371,6 @@ Init_date_core(void)
     rb_define_singleton_method(cDate, "jd", date_s_jd, -1);
     rb_define_singleton_method(cDate, "ordinal", date_s_ordinal, -1);
     rb_define_singleton_method(cDate, "civil", date_s_civil, -1);
-    rb_define_singleton_method(cDate, "new", date_s_civil, -1);
     rb_define_singleton_method(cDate, "commercial", date_s_commercial, -1);
 
 #ifndef NDEBUG
@@ -9396,6 +9398,7 @@ Init_date_core(void)
     rb_define_singleton_method(cDate, "_jisx0301", date_s__jisx0301, 1);
     rb_define_singleton_method(cDate, "jisx0301", date_s_jisx0301, -1);
 
+    rb_define_method(cDate, "initialize", date_initialize, -1);
     rb_define_method(cDate, "initialize_copy", d_lite_initialize_copy, 1);
 
 #ifndef NDEBUG