Re: and then... (a curiosity)

["Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>]

Adam Beneschan wrote:
> 
> "and then" is not a function, however, and has none of these
> properties.
> 
> To make "and" [and "or"] on two Booleans behave like the short-circuit
> form would introduce a major inconsistency into the language.

In addition to the other reasons, there's the question of processor 
optimization. Although we have a sequential view of how code is executed, modern 
processors do all sorts of strange optimizations, such as speculative execution, 
that violate that sequential view. It's my understanding that the short-circuit 
forms can prevent such optimizations. Apparently, code that may evaluate only 
one of the 2 expressions can actually be slower than code that must evaluate both.

-- 
Jeff Carter
"If I could find a sheriff who so offends the citizens of Rock
Ridge that his very appearance would drive them out of town ...
but where would I find such a man? Why am I asking you?"
Blazing Saddles
37