New class for Date objects: caches individual date components.

src/date.js

Index: src/date.js
diff --git a/src/date.js b/src/date.js
index 999009e8639089bef4ef59493ebda191d2d29ebb..28a83dccf66ad24bb7e0009c7d75ddc94fcc8a5b 100644
--- a/src/date.js
+++ b/src/date.js
@@ -452,7 +452,7 @@ var Date_cache = {
     var time = MakeTime(hours, minutes, seconds, ms);
     value = TimeClip(UTC(MakeDate(day, time)));
   }
-  %_SetValueOf(this, value);
+  SET_DATE_VALUE(this, value);
 });
 
 
@@ -565,7 +565,7 @@ function DateUTC(year, month, date, hours, minutes, seconds, ms) {
           TO_INTEGER(year) <= 99) ? 1900 + TO_INTEGER(year) : year;
   var day = MakeDay(year, month, date);
   var time = MakeTime(hours, minutes, seconds, ms);
-  return %_SetValueOf(this, TimeClip(MakeDate(day, time)));
+  return TimeClip(MakeDate(day, time));
 }
 
 
@@ -774,7 +774,7 @@ function DateGetTimezoneOffset() {
 // ECMA 262 - 15.9.5.27
 function DateSetTime(ms) {
   if (!IS_DATE(this)) ThrowDateTypeError();
-  return %_SetValueOf(this, TimeClip(ToNumber(ms)));
+  return SET_DATE_VALUE(this, TimeClip(ToNumber(ms)));
 }
 
 
@@ -786,7 +786,7 @@ function DateSetMilliseconds(ms) {
                       MIN_FROM_TIME(t),
                       SEC_FROM_TIME(t),
                       ms);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(DAY(t), time))));
+  return SET_DATE_VALUE(this, TimeClip(UTC(MakeDate(DAY(t), time))));
 }
 
 
@@ -798,7 +798,7 @@ function DateSetUTCMilliseconds(ms) {
                       MIN_FROM_TIME(t),
                       SEC_FROM_TIME(t),
                       ms);
-  return %_SetValueOf(this, TimeClip(MakeDate(DAY(t), time)));
+  return SET_DATE_VALUE(this, TimeClip(MakeDate(DAY(t), time)));
 }
 
 
@@ -808,7 +808,7 @@ function DateSetSeconds(sec, ms) {
   sec = ToNumber(sec);
   ms = %_ArgumentsLength() < 2 ? NAN_OR_MS_FROM_TIME(t) : ToNumber(ms);
   var time = MakeTime(HOUR_FROM_TIME(t), MIN_FROM_TIME(t), sec, ms);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(DAY(t), time))));
+  return SET_DATE_VALUE(this, TimeClip(UTC(MakeDate(DAY(t), time))));
 }
 
 
@@ -818,7 +818,7 @@ function DateSetUTCSeconds(sec, ms) {
   sec = ToNumber(sec);
   ms = %_ArgumentsLength() < 2 ? NAN_OR_MS_FROM_TIME(t) : ToNumber(ms);
   var time = MakeTime(HOUR_FROM_TIME(t), MIN_FROM_TIME(t), sec, ms);
-  return %_SetValueOf(this, TimeClip(MakeDate(DAY(t), time)));
+  return SET_DATE_VALUE(this, TimeClip(MakeDate(DAY(t), time)));
 }
 
 
@@ -830,7 +830,7 @@ function DateSetMinutes(min, sec, ms) {
   sec = argc < 2 ? NAN_OR_SEC_FROM_TIME(t) : ToNumber(sec);
   ms = argc < 3 ? NAN_OR_MS_FROM_TIME(t) : ToNumber(ms);
   var time = MakeTime(HOUR_FROM_TIME(t), min, sec, ms);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(DAY(t), time))));
+  return SET_DATE_VALUE(this, TimeClip(UTC(MakeDate(DAY(t), time))));
 }
 
 
@@ -842,7 +842,7 @@ function DateSetUTCMinutes(min, sec, ms) {
   sec = argc < 2 ? NAN_OR_SEC_FROM_TIME(t) : ToNumber(sec);
   ms = argc < 3 ? NAN_OR_MS_FROM_TIME(t) : ToNumber(ms);
   var time = MakeTime(HOUR_FROM_TIME(t), min, sec, ms);
-  return %_SetValueOf(this, TimeClip(MakeDate(DAY(t), time)));
+  return SET_DATE_VALUE(this, TimeClip(MakeDate(DAY(t), time)));
 }
 
 
@@ -855,7 +855,7 @@ function DateSetHours(hour, min, sec, ms) {
   sec = argc < 3 ? NAN_OR_SEC_FROM_TIME(t) : ToNumber(sec);
   ms = argc < 4 ? NAN_OR_MS_FROM_TIME(t) : ToNumber(ms);
   var time = MakeTime(hour, min, sec, ms);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(DAY(t), time))));
+  return SET_DATE_VALUE(this, TimeClip(UTC(MakeDate(DAY(t), time))));
 }
 
 
@@ -868,7 +868,7 @@ function DateSetUTCHours(hour, min, sec, ms) {
   sec = argc < 3 ? NAN_OR_SEC_FROM_TIME(t) : ToNumber(sec);
   ms = argc < 4 ? NAN_OR_MS_FROM_TIME(t) : ToNumber(ms);
   var time = MakeTime(hour, min, sec, ms);
-  return %_SetValueOf(this, TimeClip(MakeDate(DAY(t), time)));
+  return SET_DATE_VALUE(this, TimeClip(MakeDate(DAY(t), time)));
 }
 
 
@@ -877,7 +877,7 @@ function DateSetDate(date) {
   var t = LocalTime(DATE_VALUE(this));
   date = ToNumber(date);
   var day = MakeDay(YearFromTime(t), MonthFromTime(t), date);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
+  return SET_DATE_VALUE(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
 }
 
 
@@ -886,7 +886,7 @@ function DateSetUTCDate(date) {
   var t = DATE_VALUE(this);
   date = ToNumber(date);
   var day = MakeDay(YearFromTime(t), MonthFromTime(t), date);
-  return %_SetValueOf(this, TimeClip(MakeDate(day, TimeWithinDay(t))));
+  return SET_DATE_VALUE(this, TimeClip(MakeDate(day, TimeWithinDay(t))));
 }
 
 
@@ -896,7 +896,7 @@ function DateSetMonth(month, date) {
   month = ToNumber(month);
   date = %_ArgumentsLength() < 2 ? NAN_OR_DATE_FROM_TIME(t) : ToNumber(date);
   var day = MakeDay(YearFromTime(t), month, date);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
+  return SET_DATE_VALUE(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
 }
 
 
@@ -906,7 +906,7 @@ function DateSetUTCMonth(month, date) {
   month = ToNumber(month);
   date = %_ArgumentsLength() < 2 ? NAN_OR_DATE_FROM_TIME(t) : ToNumber(date);
   var day = MakeDay(YearFromTime(t), month, date);
-  return %_SetValueOf(this, TimeClip(MakeDate(day, TimeWithinDay(t))));
+  return SET_DATE_VALUE(this, TimeClip(MakeDate(day, TimeWithinDay(t))));
 }
 
 
@@ -919,7 +919,7 @@ function DateSetFullYear(year, month, date) {
   month = argc < 2 ? MonthFromTime(t) : ToNumber(month);
   date = argc < 3 ? DateFromTime(t) : ToNumber(date);
   var day = MakeDay(year, month, date);
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
+  return SET_DATE_VALUE(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
 }
 
 
@@ -932,7 +932,7 @@ function DateSetUTCFullYear(year, month, date) {
   month = argc < 2 ? MonthFromTime(t) : ToNumber(month);
   date = argc < 3 ? DateFromTime(t) : ToNumber(date);
   var day = MakeDay(year, month, date);
-  return %_SetValueOf(this, TimeClip(MakeDate(day, TimeWithinDay(t))));
+  return SET_DATE_VALUE(this, TimeClip(MakeDate(day, TimeWithinDay(t))));
 }
 
 
@@ -962,11 +962,11 @@ function DateSetYear(year) {
   var t = LocalTime(DATE_VALUE(this));
   if (NUMBER_IS_NAN(t)) t = 0;
   year = ToNumber(year);
-  if (NUMBER_IS_NAN(year)) return %_SetValueOf(this, $NaN);
+  if (NUMBER_IS_NAN(year)) return SET_DATE_VALUE(this, $NaN);
   year = (0 <= TO_INTEGER(year) && TO_INTEGER(year) <= 99)
       ? 1900 + TO_INTEGER(year) : year;
   var day = MakeDay(year, MonthFromTime(t), DateFromTime(t));
-  return %_SetValueOf(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
+  return SET_DATE_VALUE(this, TimeClip(UTC(MakeDate(day, TimeWithinDay(t)))));
 }