Posted by Steve on 01/07/08 17:47

"Michael Fesser" <netizen@gmx.de> wrote in message
news:75n4o35njta3ih1ksclpkd5od9moneb149@4ax.com...
> .oO(Steve)
>
>>"Michael Fesser" <netizen@gmx.de> wrote in message
>>news:pmk4o3trg1johm5rcaiho04qaos5kbd5rg@4ax.com...
>>
>>> PHP uses lazy evaluation. As soon as the result is known, the evaluation
>>> stops. Because of this behaviour you can write things like
>>
>>more pragmatic than lazy. if one condition is false, there is no possible
>>way other &&'ed conditions could change that result...so, why continue the
>>evaluation?
>
> Correct, and one common name for that technique is "lazy evaluation" (or
> "delayed evaluation"): the result of an expression is only calculated if
> and when it's really necessary.
>
>>most languages do it this way. of those that i've used, vb was the only
>>one
>>that continued to blindly evaluate conditions. it wasn't until vb.net that
>>the AndAlso and OrElse short-circuit constructs were added -
>>'short-circuit'
>>being even more descriptive than 'lazy' or 'pragmatic'.
>
> AFAIK "short-circuit" is more related to logical expressions, whereas
> "lazy evaluation" is the more general name and applies to many other
> things as well.

hmmm...i didn't know that. first i'd heard of lazy eval.

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