Merge pull request #387 from jmdavis/time

Implement issue# 9337: There's no Duration.max.

src/core/time.d

@@ -73,15 +73,15 @@ ulong mach_absolute_time();
     Use the $(LREF dur) function or on of its non-generic aliases to create
     $(D Duration)s.
 
-    You cannot create a duration of months or years because the variable number
-    of days in a month or a year makes it so that you cannot convert between
-    months or years and smaller units without a specific date. Any type or
-    function which handles months or years has other functions for handling
-    those rather than using durations. For instance, $(XREF datetime, Date) has
-    $(D addYears) and $(D addMonths) for adding years and months, rather than
-    creating a duration of years or months and adding that to a
-    $(XREF datetime, Date). If you're dealing with weeks or smaller, however,
-    durations are what you use.
+    It's not possible to create a Duration of months or years, because the
+    variable number of days in a month or year makes it impossible to convert
+    between months or years and smaller units without a specific date. So,
+    nothing uses $(D Duration)s when dealing with months or years. Rather,
+    functions specific to months and years are defined. For instance,
+    $(XREF datetime, Date) has $(D add!"years") and $(D add!"months") for adding
+    years and months rather than creating a Duration of years or months and
+    adding that to a $(XREF datetime, Date). But Duration is used when dealing
+    with weeks or smaller.
 
     Examples:
 --------------------
@@ -115,11 +115,29 @@ public:
       +/
     static @property @safe pure nothrow Duration zero() { return Duration(0); }
 
+    /++
+        Largest $(D Duration) possible.
+      +/
+    static @property @safe pure nothrow Duration max() { return Duration(long.max); }
+
+    /++
+        Most negative $(D Duration) possible.
+      +/
+    static @property @safe pure nothrow Duration min() { return Duration(long.min); }
+
     unittest
     {
         assert(zero == dur!"seconds"(0));
+        assert(Duration.max == Duration(long.max));
+        assert(Duration.min == Duration(long.min));
+        assert(Duration.min < Duration.zero);
+        assert(Duration.zero < Duration.max);
+        assert(Duration.min < Duration.max);
+        assert(Duration.min - dur!"hnsecs"(1) == Duration.max);
+        assert(Duration.max + dur!"hnsecs"(1) == Duration.min);
     }
 
+
     /++
         Compares this $(D Duration) with the given $(D Duration).
 
@@ -1468,9 +1486,26 @@ struct TickDuration
       +/
     static @property @safe pure nothrow TickDuration zero() { return TickDuration(0); }
 
+    /++
+        Largest $(D TickDuration) possible.
+      +/
+    static @property @safe pure nothrow TickDuration max() { return TickDuration(long.max); }
+
+    /++
+        Most negative $(D TickDuration) possible.
+      +/
+    static @property @safe pure nothrow TickDuration min() { return TickDuration(long.min); }
+
     unittest
     {
         assert(zero == TickDuration(0));
+        assert(TickDuration.max == TickDuration(long.max));
+        assert(TickDuration.min == TickDuration(long.min));
+        assert(TickDuration.min < TickDuration.zero);
+        assert(TickDuration.zero < TickDuration.max);
+        assert(TickDuration.min < TickDuration.max);
+        assert(TickDuration.min - TickDuration(1) == TickDuration.max);
+        assert(TickDuration.max + TickDuration(1) == TickDuration.min);
     }