From: H. Peter Anvin <hpa@zytor.com>
Date: Thu, 17 Nov 2005 23:18:32 GMT
Subject: Re: Teach "approxidate" about weekday syntax
Message-ID: <437D0FC8.6000906@zytor.com>
In-Reply-To: <Pine.LNX.4.64.0511171223110.13959@g5.osdl.org>

Linus Torvalds wrote:
> This allows people to use syntax like "last thursday" for the approxidate. 
> 
> (Or, indeed, more complex "three thursdays ago", but I suspect that would 
> be pretty unusual).
> 
> NOTE! The parsing is strictly sequential, so if you do
> 
> 	"one day before last thursday"
> 
> it will _not_ do what you think it does. It will take the current time, 
> subtract one day, and then go back to the thursday before that. So to get 
> what you want, you'd have to write it the other way around:
> 
> 	"last thursday and one day before"
> 
> which is insane (it's usually the same as "last wednesday" _except_ if 
> today is Thursday, in which case "last wednesday" is yesterday, and "last 
> thursday and one day before" is eight days ago).
> 
> Similarly,
> 
> 	"last thursday one month ago"
> 
> will first go back to last thursday, and then go back one month from 
> there, not the other way around.
> 
> I doubt anybody would ever use insane dates like that, but I thought I'd 
> point out that the approxidate parsing is not exactly "standard English".
> 

I believe English would always parse from right to left, it might be the 
right thing to do...

	-hpa