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time_lang.ml
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time_lang.ml
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(* Wyrd -- a curses-based front-end for Remind
* Copyright (C) 2005, 2006, 2007, 2008, 2010, 2011-2013 Paul Pelzl
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, Version 2,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Bug reports can be entered at http://bugs.launchpad.net/wyrd .
* For anything else, feel free to contact Paul Pelzl at <[email protected]>.
*)
(* time_lang.ml
*
* This module implements a regexp-based parser for natural-language descriptions of
* events. It recognizes most reasonable permutations of ([DATE] [TIME] DESCRIPTION),
* including:
*
* "do some stuff tomorrow at 3"
* "wednesday meeting with Bob 1:30pm-3:00"
* "leave for airport noon next Fri"
* "6/14 6pm dinner with Tom"
*
* Preference is generally for US time and date conventions; would be quite difficult to
* internationalize this module. *)
exception Event_parse_error of string
let parse_failwith s = raise (Event_parse_error s)
let parse_fail_default () = parse_failwith "unrecognized format for event."
type event_t = Timed of (Unix.tm * Unix.tm) | Untimed of Unix.tm
(* DEFINE TIME AND DATE REGEXES *)
(* Note: careful when changing these regexps. If the grouping tree changes,
* then the fields may be misnumbered in code below. *)
(* Note: ocaml _really_ needs a raw string syntax to make regexps look more sane... *)
let weekdays =
"\\(\\(on[ \t]+\\)?\\(next[ \t]+\\)?" ^
"\\(\\(sunday\\|sun\\)\\|\\(monday\\|mon\\)\\|\\(tuesday\\|tue\\|tues\\)\\|" ^
"\\(wednesday\\|wed\\)\\|\\(thursday\\|thu\\|thur\\|thurs\\)\\|" ^
"\\(friday\\|fri\\)\\|\\(saturday\\|sat\\)\\)\\)"
(* typical US-style dates, like 6/1 or 6/1/2006 *)
let numeric_slash_date = "\\(\\([0-9]+\\)/\\([0-9]+\\)\\(/\\([0-9][0-9][0-9][0-9]\\)\\)?\\)"
(* ISO standard dates, like 2006-06-01 *)
let iso_date = "\\(\\([0-9][0-9][0-9][0-9]\\)-\\([0-9]+\\)-\\([0-9]+\\)\\)"
let numeric_date = "\\(\\(on[ \t]+\\)?\\(" ^ numeric_slash_date ^ "\\|" ^ iso_date ^ "\\)\\)"
let short_date =
"\\(\\(today\\)\\|\\(tomorrow\\)\\|" ^
"\\(in[ \t]+\\([0-9]+\\)[ \t]+day\\(s\\|s' time\\)?\\)\\)"
let date_spec =
"\\(" ^ weekdays ^ "\\|" ^ numeric_date ^ "\\|" ^ short_date ^ "\\)"
(* 5, or 5:30, or 5pm, or 5:30 pm *)
let time_spec =
"\\(\\(\\([0-9][0-9]?\\)\\(:\\([0-9][0-9]\\)\\)?[ \t]*\\(am\\|pm\\)?\\)\\|" ^
"\\(noon\\|midnight\\)\\)"
(* either match a single time spec, or match a pair formatted as a range:
* 5-7 or 5:30pm-7 or 5 until 7 or 5:30 to 7pm ... *)
let time_range_spec =
"\\(\\(at[ \t]+\\)?" ^ time_spec ^ "\\([ \t]*\\(-\\|to\\|\\until\\)[ \t]*" ^
time_spec ^ "\\)?\\)"
let date_start_regex = Str.regexp_case_fold ("[ \t,.]*" ^ date_spec ^ "[ \t,.]+")
let time_start_regex = Str.regexp_case_fold ("[ \t,.]*" ^ time_range_spec ^ "[ \t,.]+")
let date_end_regex = Str.regexp_case_fold ("[ \t,.]+" ^ date_spec ^ "[ \t,.]*$")
let time_end_regex = Str.regexp_case_fold ("[ \t,.]+" ^ time_range_spec ^ "[ \t,.]*$")
(* given a current time and an hour/minute/merid specifier,
* search forward from current time and provide the next time
* value that satisfies the spec. *)
(* 'future' is a boolean variable that determines whether the time
* is required to be in the future or not (i.e. the present is acceptable) *)
let next_matching_time future curr_tm hour min merid =
let (curr, _) = Unix.mktime curr_tm in
let get_tm hour_shift day_shift =
let tm = {
curr_tm with Unix.tm_hour = hour + hour_shift;
Unix.tm_min = min;
Unix.tm_sec = 0;
Unix.tm_mday = curr_tm.Unix.tm_mday + day_shift
} in
Unix.mktime tm
in
if merid = "am" then
(* if "am" is specified... *)
(* try using the hour and minute as given *)
let (start1, start1_tm) = get_tm 0 0 in
if start1 > curr || (start1 = curr && not future) then
start1_tm
else
(* if that fails, just use the same time tomorrow *)
let (start2, start2_tm) = get_tm 0 1 in
start2_tm
else if merid = "pm" then
(* if "pm" is specified... *)
(* try using the hour and minute as given (but shifted to afternoon) *)
let (start1, start1_tm) = get_tm 12 0 in
if start1 > curr || (start1 = curr && not future) then
start1_tm
else
(* if that fails, use the same time tomorrow *)
let (start2, start2_tm) = get_tm 12 1 in
start2_tm
else
(* if neither "am" nor "pm" are specified... *)
(* first use the hour and minute as given *)
let (start1, start1_tm) = get_tm 0 0 in
if start1 > curr || (start1 = curr && not future) then
start1_tm
else
(* if that fails, look in the afternoon *)
let (start2, start2_tm) = get_tm 12 0 in
if start2 > curr || (start2 = curr && not future) then
start2_tm
else
(* if that fails, shift to tomorrow morning *)
let (start3, start3_tm) = get_tm 0 1 in
start3_tm
(* Find the next timespec following curr_tm that falls on 'wday'. 'next_week'
* is a boolean variable that is true if the event should be interpreted
* as occurring next week. *)
let find_next_wday curr_tm wday next_week =
(* start scanning forward from the current timespec, unless the 'next'
* specifier is given; in that case, start from the beginning of
* next week *)
let scan_from =
if next_week then
let week_diff =
if !Rcfile.week_starts_monday then
7 - ((curr_tm.Unix.tm_wday + 6) mod 7)
else
7 - curr_tm.Unix.tm_wday
in
let temp = {
curr_tm with Unix.tm_mday = curr_tm.Unix.tm_mday + week_diff;
Unix.tm_hour = 0;
Unix.tm_min = 0;
Unix.tm_sec = 0
} in
let (_, norm) = Unix.mktime temp in
norm
else
curr_tm
in
let diff =
if wday > scan_from.Unix.tm_wday then
wday - scan_from.Unix.tm_wday
else if wday = scan_from.Unix.tm_wday && next_week then
0
else
wday - scan_from.Unix.tm_wday + 7
in
let temp = {
scan_from with Unix.tm_mday = scan_from.Unix.tm_mday + diff;
Unix.tm_hour = 0;
Unix.tm_min = 0;
Unix.tm_sec = 0
} in
let (_, norm) = Unix.mktime temp in
norm
(* Find the next timespec following curr_tm that satisfies the
* month and day provided. *)
let find_next_mon_mday curr_tm mon mday =
if mon > curr_tm.Unix.tm_mon then
let temp = {
curr_tm with Unix.tm_mon = mon;
Unix.tm_mday = mday;
Unix.tm_hour = 0;
Unix.tm_min = 0;
Unix.tm_sec = 0
} in
let (_, norm) = Unix.mktime temp in
norm
else if mon = curr_tm.Unix.tm_mon && mday > curr_tm.Unix.tm_mday then
let temp = {
curr_tm with Unix.tm_mday = mday;
Unix.tm_hour = 0;
Unix.tm_min = 0;
Unix.tm_sec = 0
} in
let (_, norm) = Unix.mktime temp in
norm
else
let temp = {
curr_tm with Unix.tm_year = succ curr_tm.Unix.tm_year;
Unix.tm_mon = mon;
Unix.tm_mday = mday;
Unix.tm_hour = 0;
Unix.tm_min = 0;
Unix.tm_sec = 0
} in
let (_, norm) = Unix.mktime temp in
norm
(* Parse a natural language date string. *)
let parse_natural_language_date date_str =
let current = Unix.localtime (Unix.time ()) in
let (_, current_tm) = Unix.mktime current in
let date_regex = Str.regexp date_spec in
if Str.string_match date_regex date_str 0 then begin
(*
for i = 1 to 30 do
try
Printf.printf "%2d: \"%s\"\n" i (Str.matched_group i date_str); flush stdout;
with Not_found -> ()
done;
*)
let get_field num = Str.matched_group num date_str in
let handle_weekday () =
let has_next =
try
let _ = get_field 4 in true
with Not_found -> false
in
try
(* some variant of "sunday" *)
let _ = get_field 6 in
find_next_wday current_tm 0 has_next
with Not_found ->
try
(* some variant of "monday" *)
let _ = get_field 7 in
find_next_wday current_tm 1 has_next
with Not_found ->
try
(* some variant of "tuesday" *)
let _ = get_field 8 in
find_next_wday current_tm 2 has_next
with Not_found ->
try
(* some variant of "wednesday" *)
let _ = get_field 9 in
find_next_wday current_tm 3 has_next
with Not_found ->
try
(* some variant of "thursday" *)
let _ = get_field 10 in
find_next_wday current_tm 4 has_next
with Not_found ->
try
(* some variant of "friday" *)
let _ = get_field 11 in
find_next_wday current_tm 5 has_next
with Not_found ->
try
(* some variant of "saturday" *)
let _ = get_field 12 in
find_next_wday current_tm 6 has_next
with Not_found ->
parse_failwith "please submit a bug report for \"unreachable case 3\"."
in
let handle_numeric_slash () =
try
(* US-style numeric date specified with slashes *)
let first = int_of_string (get_field 17) in
let second = int_of_string (get_field 18) in
let (month, monthday) =
if !Rcfile.quick_date_US then
(* assume US conventions (month first, then day of month) *)
(first, second)
else
(* assume non-US conventions (day of month first, then month) *)
(second, first)
in
if month >= 1 && month <= 12 && monthday >= 1 && monthday <= 31 then
begin try
let third = int_of_string (get_field 20) in
if third >= 1991 && third <= 2037 then
let temp = {
current_tm with Unix.tm_year = third - 1900;
Unix.tm_mon = pred month;
Unix.tm_mday = monthday;
Unix.tm_hour = 0;
Unix.tm_min = 0;
Unix.tm_sec = 0
} in
let (_, norm) = Unix.mktime temp in
norm
else
parse_fail_default ()
with Not_found ->
find_next_mon_mday current_tm (pred month) monthday
end
else
parse_fail_default ()
with Not_found ->
parse_failwith "please submit a bug report for \"unreachable case 4\"."
in
let handle_iso () =
try
(* iso numeric date specified with dashes *)
let first = int_of_string (get_field 22) in
let second = int_of_string (get_field 23) in
let third = int_of_string (get_field 24) in
if first >= 1991 && first <= 2037 &&
second >= 1 && second <= 12 &&
third >= 1 && third <= 31 then
let temp = {
current_tm with Unix.tm_year = first - 1900;
Unix.tm_mon = pred second;
Unix.tm_mday = third;
Unix.tm_hour = 0;
Unix.tm_min = 0;
Unix.tm_sec = 0
} in
let (_, norm) = Unix.mktime temp in
norm
else
parse_fail_default ()
with Not_found ->
parse_failwith "please submit a bug report for \"unreachable case 5\"."
in
let handle_short () =
try
(* "today" *)
let _ = get_field 26 in
let temp = {
current_tm with Unix.tm_hour = 0;
Unix.tm_min = 0;
Unix.tm_sec = 0
} in
let (_, norm) = Unix.mktime temp in
norm
with Not_found ->
try
(* "tomorrow" *)
let _ = get_field 27 in
let temp = {
current_tm with Unix.tm_mday = succ current_tm.Unix.tm_mday;
Unix.tm_hour = 0;
Unix.tm_min = 0;
Unix.tm_sec = 0
} in
let (_, norm) = Unix.mktime temp in
norm
with Not_found ->
try
(* "in N days" *)
let num = int_of_string (get_field 29) in
let temp = {
current_tm with Unix.tm_mday = current_tm.Unix.tm_mday + num;
Unix.tm_hour = 0;
Unix.tm_min = 0;
Unix.tm_sec = 0
} in
let (_, norm) = Unix.mktime temp in
norm
with Not_found ->
parse_failwith "please submit a bug report for \"unreachable case 6\"."
in
let date_tm =
try
(* a weekday specifier *)
let _ = get_field 5 in
handle_weekday ()
with Not_found ->
try
(* a numeric date specifier with slashes *)
let _ = get_field 16 in
handle_numeric_slash ()
with Not_found ->
try
(* a numeric date specifier with dashes *)
let _ = get_field 21 in
handle_iso ()
with Not_found ->
try
(* a shortcut date *)
let _ = get_field 25 in
handle_short ()
with Not_found ->
parse_failwith "please submit a bug report for \"unreachable case 2\"."
in
date_tm
end else
parse_failwith "please submit a bug report for \"unreachable case 1\"."
(* Parse a natural language time string. *)
(* 'future' is a boolean variable that determines whether the time
* is required to be in the future or not (i.e. the present is acceptable) *)
let parse_natural_language_time future current_tm time_str =
let time_regex = Str.regexp time_range_spec in
if Str.string_match time_regex time_str 0 then begin
(*
for i = 1 to 30 do
try
Printf.printf "%2d: \"%s\"\n" i (Str.matched_group i time_str); flush stdout;
with
| Not_found -> ()
done;
*)
let get_field num =
try Str.matched_group num time_str with Not_found -> ""
in
let start_hour_s = get_field 5
and start_minute_s = get_field 7
and start_meridien_s = get_field 8
and end_hour_s = get_field 14
and end_minute_s = get_field 16
and end_meridien_s = get_field 17
and start_abbrev = get_field 9
and end_abbrev = get_field 18 in
(* OK, given a timestamp as context, try to choose the most sensible
* interpretation of the time spec. Search forward from current time for
* the first start time that matches, then continue searching forward
* for the first end time that matches. *)
let (start_hour, start_meridien) =
if start_abbrev = "noon" then
(0, "pm")
else if start_abbrev = "midnight" then
(0, "am")
else if start_hour_s = "" then
parse_fail_default ()
else
let temp = int_of_string start_hour_s in
if temp = 0 then
(0, "am")
else if temp >= 13 && temp <= 23 then
(temp - 12, "pm")
else if temp >= 1 && temp <= 11 then
(temp, start_meridien_s)
else if temp = 12 then
(0, start_meridien_s)
else
parse_fail_default ()
in
let start_minute =
if start_minute_s = "" then
0
else
let temp = int_of_string start_minute_s in
if temp >= 0 && temp <= 59 then
temp
else
parse_fail_default ()
in
let start_tm =
next_matching_time future current_tm start_hour start_minute start_meridien
in
let end_tm =
if end_hour_s = "" && end_abbrev = "" then
start_tm
else
let (end_hour, end_meridien) =
if end_abbrev = "noon" then
(0, "pm")
else if end_abbrev = "midnight" then
(0, "am")
else
let temp = int_of_string end_hour_s in
if temp = 0 then
(0, "am")
else if temp >= 13 && temp <= 23 then
(temp - 12, "pm")
else if temp >= 1 && temp <= 11 then
(temp, end_meridien_s)
else if temp = 12 then
(0, end_meridien_s)
else
parse_fail_default ()
in
let end_minute =
if end_minute_s = "" then
0
else
let temp = int_of_string end_minute_s in
if temp >= 0 && temp <= 59 then
temp
else
parse_fail_default ()
in
next_matching_time true start_tm end_hour end_minute end_meridien
in
(start_tm, end_tm)
end else
parse_failwith "please submit a bug report for \"unreachable case 10\"."
(* at the beginning of the string, searches for date, then time,
* then date again, then time again, as necessary *)
let rec find_date_time_begin date time event_remainder attempts =
let find_element_gen element_start_regex element event_s =
match element with
| None ->
if Str.string_match element_start_regex event_s 0 then begin
let new_element = String.lowercase (Str.matched_group 1 event_s) in
let pos = Str.match_end () in
let new_event_s = Str.string_after event_s pos in
((Some new_element), new_event_s)
end else
(element, event_s)
| Some _ ->
(element, event_s)
in
let find_date = find_element_gen date_start_regex in
let find_time = find_element_gen time_start_regex in
if attempts >= 2 then
(date, time, event_remainder)
else
let (new_date, event_remainder2) = find_date date event_remainder in
let (new_time, event_remainder3) = find_time time event_remainder2 in
find_date_time_begin new_date new_time event_remainder3 (succ attempts)
(* at the end of the string, searches for date, then time,
* then date again, then time again, as necessary *)
let rec find_date_time_end date time event_remainder attempts =
let find_element_gen element_end_regex element event_s =
match element with
| None ->
begin try
let pos = Str.search_forward element_end_regex event_s 0 in
let new_element = String.lowercase (Str.matched_group 1 event_s) in
let new_event_s = Str.string_before event_s pos in
((Some new_element), new_event_s)
with Not_found ->
(element, event_s)
end
| Some _ ->
(element, event_s)
in
let find_date = find_element_gen date_end_regex in
let find_time = find_element_gen time_end_regex in
if attempts >= 2 then
(date, time, event_remainder)
else
let (new_date, event_remainder2) = find_date date event_remainder in
let (new_time, event_remainder3) = find_time time event_remainder2 in
find_date_time_end new_date new_time event_remainder3 (succ attempts)
(* Primary function of this module. Parses a natural language definition for an event,
* which might look something like "Wednesday meeting with Bob at 9:30pm." *)
let parse_natural_language_event event_str =
let (date, time, description) =
(* search at the start of the string first, then at the end *)
let (date_begin, time_begin, remainder) =
find_date_time_begin None None event_str 0
in
find_date_time_end date_begin time_begin remainder 0
in
let curr_tm = Unix.localtime (Unix.time ()) in
let rem_spec =
match date with
| None ->
begin match time with
| None ->
parse_fail_default ()
| Some time_str ->
Timed (parse_natural_language_time true curr_tm time_str)
end
| Some date_str ->
let date_tm = parse_natural_language_date date_str in
begin match time with
| None ->
Untimed date_tm
| Some time_str ->
Timed (parse_natural_language_time false date_tm time_str)
end
in
(rem_spec, description)
(* arch-tag: DO_NOT_CHANGE_a43ce66f-688e-42dd-8c2b-83b55c124a5a *)