ndp

ndp is a "natural date parser" library. It allows you to convert natural language user input to a more machine-friendly time value.

## Demo
An example utility is provided called readdate.lua, which reads lines from stdin, and 
prints the interpreted date along with any text that wasn't considered part of the time 
specification.

## Examples

today
=> Sun Jun 21 23:45:57 2009 (1245624357) [?,?]

feed the cat in the morning
=> Mon Jun 22 09:30:09 2009 (1245659409): feed the cat [13,28]

go shopping next tuesday
=> Tue Jun 23 23:46:27 2009 (1245797187): go shopping next [17,25]

service the car in September
=> Mon Sep 21 23:46:48 2009 (1253573208): service the car [16,29]

Watch the games in July 2012
=> Sat Jul 21 23:48:06 2012 (1342910886): Watch the games [16,29]

## Usage

...is simple :)

To get a time from an input string, simply do:

   local ndp = require "ndp"; -- Load the ndp library
   local mytime = ndp.when("tomorrow"); -- Get the date tomorrow
   print(os.date("%c", mytime)); -- Print it out

A slightly more advanced usage is extracting information in the input string which 
was not concerned with the time. This is useful for extracting things like "feed the cat" 
from "feed the cat tomorrow afternoon". ndp.when() returns 2 extra values which are the start 
and finish positions of the text it actually used in the string. By removing the text between 
these positions you will be left with the real data.

   local ndp = require "ndp"; -- Load the ndp library
   local mytime, startpos, endpos = ndb.when("tomorrow afternoon, feed the cat");
   local message = (line:sub(1, start)..line:sub(finish, -1)) -- returns ", feed the cat"
   -- To make things a bit neater, we can use Lua's gsub function to trim leftover spaces and
   -- punctuation from the result:
   message = message:gsub("^[%s%p]+", ""):gsub("[%s%p]+$", "");
   print(message); -- feed the cat