[PATCH v4 8/9] man: document the date:since..until range queries

[Jani Nikula <jani@nikula.org>]

---
 man/man7/notmuch-search-terms.7 |  147 +++++++++++++++++++++++++++++++++++----
 1 file changed, 135 insertions(+), 12 deletions(-)

diff --git a/man/man7/notmuch-search-terms.7 b/man/man7/notmuch-search-terms.7
index 17a109e..fbd3ee7 100644
--- a/man/man7/notmuch-search-terms.7
+++ b/man/man7/notmuch-search-terms.7
@@ -54,6 +54,8 @@ terms to match against specific portions of an email, (where
 
 	folder:<directory-path>
 
+	date:<since>..<until>
+
 The
 .B from:
 prefix is used to match the name or address of the sender of an email
@@ -104,6 +106,26 @@ contained within particular directories within the mail store. Only
 the directory components below the top-level mail database path are
 available to be searched.
 
+The
+.B date:
+prefix can be used to restrict the results to only messages within a
+particular time range (based on the Date: header) with a range syntax
+of:
+
+	date:<since>..<until>
+
+See \fBDATE AND TIME SEARCH\fR below for details on the range
+expression, and supported syntax for <since> and <until> date and time
+expressions.
+
+The time range can also be specified using timestamps with a syntax
+of:
+
+	<initial-timestamp>..<final-timestamp>
+
+Each timestamp is a number representing the number of seconds since
+1970\-01\-01 00:00:00 UTC.
+
 In addition to individual terms, multiple terms can be
 combined with Boolean operators (
 .BR and ", " or ", " not
@@ -117,20 +139,121 @@ operators, but will have to be protected from interpretation by the
 shell, (such as by putting quotation marks around any parenthesized
 expression).
 
-Finally, results can be restricted to only messages within a
-particular time range, (based on the Date: header) with a syntax of:
+.SH DATE AND TIME SEARCH
 
-	<initial-timestamp>..<final-timestamp>
+This is a non-exhaustive description of the date and time search with
+some pseudo notation. Most of the constructs can be mixed freely, and
+in any order, but the same absolute date or time can't be expressed
+twice.
 
-Each timestamp is a number representing the number of seconds since
-1970\-01\-01 00:00:00 UTC. This is not the most convenient means of
-expressing date ranges, but until notmuch is fixed to accept a more
-convenient form, one can use the date program to construct
-timestamps. For example, with the bash shell the following syntax would
-specify a date range to return messages from 2009\-10\-01 until the
-current time:
-
-	$(date +%s \-d 2009\-10\-01)..$(date +%s)
+.RS 4
+.TP 4
+.B The range expression
+
+date:<since>..<until>
+
+The above expression restricts the results to only messages from
+<since> to <until>, based on the Date: header.
+
+If <since> or <until> describes time at an accuracy of days or less,
+the date/time is rounded, towards past for <since> and towards future
+for <until>, to be inclusive. For example, date:january..february
+matches from the beginning of January until the end of
+February. Similarly, date:yesterday..yesterday matches from the
+beginning of yesterday until the end of yesterday.
+
+Open-ended ranges are supported (since Xapian 1.2.1), i.e. it's
+possible to specify date:..<until> or date:<since>.. to not limit the
+start or end time, respectively. Unfortunately, pre-1.2.1 Xapian does
+not report an error on open ended ranges, but it does not work as
+expected either.
+
+Xapian does not support spaces in range expressions. You can replace
+the spaces with '_', or (in most cases) '-', or (in some cases) leave
+the spaces out altogether.
+
+Entering date:expr without ".." (for example date:yesterday) won't
+work, as it's not interpreted as a range expression at all. You can
+achieve the expected result by duplicating the expr both sides of ".."
+(for example date:yesterday..yesterday).
+.RE
+
+.RS 4
+.TP 4
+.B Relative date and time
+[N|number] (years|months|weeks|days|hours|hrs|minutes|mins|seconds|secs) [...]
+
+All refer to past, can be repeated and will be accumulated.
+
+Units can be abbreviated to any length, with the otherwise ambiguous
+single m being m for minutes and M for months.
+
+Number multiplier can also be written out one, two, ..., ten, dozen,
+hundred. As special cases last means one ("last week") and this means
+zero ("this month").
+
+When combined with absolute date and time, the relative date and time
+specification will be relative from the specified absolute date and
+time.
+
+Examples: 5M2d, two weeks
+.RE
+
+.RS 4
+.TP 4
+.B Supported time formats
+H[H]:MM[:SS] [(am|a.m.|pm|p.m.)]
+
+H[H] (am|a.m.|pm|p.m.)
+
+HHMMSS
+
+now
+
+noon
+
+midnight
+
+Examples: 17:05, 5pm
+.RE
+
+.RS 4
+.TP 4
+.B Supported date formats
+YYYY-MM[-DD]
+
+DD-MM[-[YY]YY]
+
+MM-YYYY
+
+M[M]/D[D][/[YY]YY]
+
+M[M]/YYYY
+
+D[D].M[M][.[YY]YY]
+
+D[D][(st|nd|rd|th)] Mon[thname] [YYYY]
+
+Mon[thname] D[D][(st|nd|rd|th)] [YYYY]
+
+Wee[kday]
+
+Month names can be abbreviated at three or more characters.
+
+Weekday names can be abbreviated at three or more characters.
+
+Examples: 2012-07-31, 31-07-2012, 7/31/2012, August 3
+.RE
+
+.RS 4
+.TP 4
+.B Time zones
+(+|-)HH:MM
+
+(+|-)HH[MM]
+
+Some time zone codes, e.g. UTC, EET.
+.RE
 
 .SH SEE ALSO
 
-- 
1.7.9.5