[Dev] Smart Date/Time Parsing

[Donn Denman]

Should we roll our own "smart" Date/Time parser?  Or should we find and 
modify an existing system?

Ted faced a similar question when deciding on a query language for 
Chandler.  We can probably learn from his decision process.  We may 
also want to consider using the technology that he ultimately chose - 
the Yapps parser, since it's already being used in Chandler.

To help us make this decision it would be helpful to have a good 
understanding of the requirements.  We've talked about "smart parsing" 
of DateTime expressions, and I have a feel for the kinds of things they 
could do.  Is there a wiki page on this?  If not, maybe we can start 
one.

Off the top of my head, it seems like the requirements include:
    * Day names, like "Today", "Tomorrow", and "next Thursday"
    * Time abbreviations, like using "3" for "3:00 PM"
    * Time Zone names and abbreviations, like "PST", or "Pacific" for 
Pacific Standard Time
    * Some native language constructs, like the conjunction "at" in 
"Tomorrow at 3"
    * Names for times, like "noon"
    * Support for durations, like "an hour"
    * Support for All-Day and Any-Time