Re: [PATCH 3/3] Teach 'diff' about 'nodiff' attribute.

On Friday 2007, April 13, Johannes Sixt wrote:

There's nothing wrong with double negatives per se. They often confer more meaning than simple logic would suggest.

For example:

 I can't not hate CVS
 I hate CVS

Logically identical, but semantically different. In the first, the speak would be suggesting that they've tried, but failed, to like CVS; in the second the speaker just hates it. Language isn't logic, it's fuzzy logic :-).

The reason I think it's relevant to bring this up is that I think identifier naming in programming should try to use language to lead the reader down the same thought path as the writer.

You want a flag that controls whether a thread is running - should it be called RunFlag or StopFlag?

 while( RunFlag )

 while( !StopFlag )

I think that the context is important.

I, personally, wouldn't like to say which is correct in that case - or in the "nodiff"/"!diff" question. However, I don't think it's correct to universally rule out all double negative use - they have their place.

Andy