--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ndp.lua Sun Jun 21 17:42:50 2009 +0100
@@ -0,0 +1,137 @@
+module(..., package.seeall);
+
+require "luarocks.require"
+require "lpeg"
+
+-- Add case-insensitive string matching to Lpeg
+function lpeg.Pi(s)
+ local patt = lpeg.P(true);
+ for c in s:gmatch(".") do
+ patt = patt * (lpeg.P(c:lower()) + lpeg.P(c:upper()));
+ end
+ return patt;
+end
+
+function lpeg.one_of(list)
+ local patt = lpeg.P(false);
+ for _, match in ipairs(list) do
+ patt = patt + lpeg.Pi(match);
+ end
+ return patt;
+end
+
+local ordinal = lpeg.P{ lpeg.C(lpeg.R("09")^-2) * (lpeg.Pi("st") + lpeg.Pi("nd") + lpeg.Pi("rd") + lpeg.Pi("th")) + 1 * lpeg.V(1) };
+local number = lpeg.R "09"^1
+
+local day_name = lpeg.one_of {'monday', 'tuesday', 'wednesday',
+ 'thursday', 'friday', 'saturday', 'sunday'}
+
+local month_name = lpeg.one_of {'january', 'february', 'march', 'april', 'may', 'june',
+ 'july', 'august', 'september', 'october', 'november', 'december' }
+
+local year = (lpeg.R("09")^4)^-4
+
+local unit_of_time = lpeg.one_of { 'second', 'minute', 'hour', 'day', 'week', 'month', 'year' }
+
+local time_of_day = lpeg.one_of { 'morning', 'noon', 'afternoon', 'evening', 'night', 'midnight' }
+local time_of_days = { morning = 09, noon = 12, afternoon = 13, evening = 17, night = 21, midnight = 00 }
+
+local quantity;
+local quantities = {
+ ["a"] = 1;
+ ["an"] = 1;
+
+ ["a couple of"] = 2;
+
+ ["a few"] = 3;
+ ["several"] = 3;
+ };
+
+-- Create 'quantity' to match any of the quantities we know
+do
+ local quantity_list = {};
+ for k in pairs(quantities) do
+ quantity_list[#quantity_list+1] = k;
+ end
+ table.sort(quantity_list, function (a,b) return #a>#b; end);
+ quantity = number + lpeg.one_of(quantity_list);
+end
+
+seconds_in_a = { second = 1 }
+seconds_in_a.minute = seconds_in_a.second * 60;
+seconds_in_a.hour = seconds_in_a.minute * 60;
+seconds_in_a.day = seconds_in_a.hour * 24;
+seconds_in_a.week = seconds_in_a.day * 7;
+seconds_in_a.month = seconds_in_a.week * 4;
+seconds_in_a.year = seconds_in_a.day * 365;
+
+local function get_time_part(time, part)
+ return os.date("*t", time)[part];
+end
+
+local function adjust_time(time, part, value)
+ local split_time = os.date("*t", time);
+
+ split_time[part] = value;
+
+ return os.time(split_time);
+end
+
+function when(str, relative_to)
+ local time = relative_to or os.time();
+ local P = lpeg.P;
+
+ local patterns =
+ {
+ { P"tomorrow" /
+ function ()
+ time = time + seconds_in_a.day;
+ end };
+ { P"next week" /
+ function ()
+ time = time + seconds_in_a.week;
+ end };
+ { P"next year" /
+ function ()
+ time = adjust_time(time, "year", get_time_part(time, "year") + 1);
+ end };
+ { P"on "^0 * day_name /
+ function (day_name)
+ time = find_nearest_day_by_name(time, day_name);
+ end };
+ { P"in "^0 * month_name /
+ function (month_name)
+ time = find_nearest_month_by_name(time, month_name);
+ end };
+ { P"in "^0 * ( quantity * P" " * unit_of_time ) * (P"s"^-1) /
+ function (number_and_unit)
+ local number, unit = number_and_unit:gsub("^in ", ""):match("^(.+)%s+(.-)s?$");
+
+ number = quantities[number] or tonumber(number);
+
+ time = time + seconds_in_a[unit] * number;
+ end };
+ { (P"this " + P"in the " + P"at ")^0 * time_of_day /
+ function (time_of_day)
+ time_of_day = time_of_day:match("%S+$");
+ time = adjust_time(time, "hour", time_of_days[time_of_day]);
+ if time_of_day == "noon" or time_of_day == "midnight" then
+ time = adjust_time(time, "min", 00);
+ else
+ time = adjust_time(time, "min", 30);
+ end
+ end };
+ }
+
+ local ret, pos;
+ for _, pattern in pairs(patterns) do
+ ret = lpeg.match(lpeg.P{ pattern[1] + 1 * lpeg.V(1) }, str);
+ if ret then
+ pos = ret;
+ --print("Matches ".._.." until "..ret);
+ end
+ end
+
+ return time, pos;
+end
+