doc/timetable: Document `normalise` fractional behaviour

[etc/awesome.git] / doc / timetable.md

diff --git a/doc/timetable.md b/doc/timetable.md
index e3601a4cd1bf11c92b83379b7ea165273d159e18..49fe046b5a494fa7bc04e635b1152737b47898aa 100644 (file)
--- a/doc/timetable.md
+++ b/doc/timetable.md
@@ -21,32 +21,37 @@ called to modify components to return to their standard range.
 Equality and comparisons should work between timetable objects.
 
 
-## `new ( year , month , day , hour , min , sec , [yday] , [wday] )`
+### `new ( year , month , day , hour , min , sec , [yday] , [wday] )`
 
 Returns a new timetable with the given contents.
 
 
-## `new_from_timestamp ( timestamp )`
+### `new_from_timestamp ( timestamp )`
 
-Returns a new timetable given a timestamp in seconds since the unix epoch of 
+Returns a new (normalised) timetable, given a timestamp in seconds since the unix epoch of 
 1970-01-01.
 
-`:normalise ( )` should probably be called before use to resolve to the current time and 
-date.
 
-
-## `:clone ( )`
+### `:clone ( )`
 
 Returns a new independent instance of an existing timetable object.
 
 
-## `:normalise ( )`
+### `:normalise ( )`
 
-Mutates the current object's time and date components so that they lie within 'normal' 
+Mutates the current object's time and date components so that are integers within 'normal'
 ranges e.g. `month` is `1`-`12`; `min` is `0`-`59`
 
+First, fractional parts are propagated down.  
+e.g. `.month=6.5` `.day=1` (which could be read as "the first day after the middle of June")
+normalises to `.month=2` `.day=16`
+
+Second, any fields outside of their normal ranges are propagated up  
+e.g. `.hour=10` `.min=100` (100 minutes past 10am)
+normalises to `.hour=11` `.min=40`
+
 
-## `:rfc_3339 ( )` and `__tostring` metamethod
+### `:rfc_3339 ( )` and `__tostring` metamethod
 
 Returns the timetable formatted as an rfc-3339 style string.
 The timezone offset (or Z) is not appended.
@@ -54,11 +59,11 @@ The ranges of components are not checked, if you want a valid timestamp,
 `:normalise ( )` should be called first.
 
 
-## `:timestamp ( )`
+### `:timestamp ( )`
 
 Returns the timetable as the number of seconds since unix epoch (1970-01-01) as a lua number.
 
 
-## `:unpack ( )`
+### `:unpack ( )`
 
 Unpacks the timetable object; returns `year`, `month`, `day`, `hour`, `min`, `sec`, `yday`, `wday`