On Friday, 1 August 2014 at 10:42:50 UTC, Marc Schütz wrote:
On Friday, 1 August 2014 at 09:02:36 UTC, Walter Bright wrote:
On 7/31/2014 11:24 PM, "Ola Fosheim Grøstad"
<[email protected]>" wrote:
On Friday, 1 August 2014 at 02:44:51 UTC, Walter Bright wrote:
That entry makes no mention of assert being used as an
optimization hint.
Saying that a predicate is always true means it's available
to the optimizer.
An assert does not say that the predicate is always true.
Yes, it does. From Meyers' comprehensive tome on the topic
"Object-Oriented Software Construction" (1997) where he writes:
"A run-time assertion violation is the manifestation of a bug
in the software."
-- pg. 346
In fact, Meyers calls it "rule (1)" of assertions.
No, the statement in this quote does not imply that it is
always true. It says that there is a bug if it isn't, which
obviously wouldn't make any sense if the predicate were always
true.
An assertion doesn't tell the compiler that a predicate is
true, it tells the compiler to _check whether_ it is true.
Even the WP article that you referred to says:
"An assertion may be used to verify that an assumption made by
the programmer [...] remains valid"
https://en.wikipedia.org/wiki/Assertion_%28software_development%29#Assertions_for_run-time_checking
It may be used to _verify_ an assumption, not to _claim_ that it
is true.
