On Tuesday, 5 August 2014 at 20:50:06 UTC, Jeremy Powers via
Digitalmars-d wrote:
Well, yes: Undefined behaviour in the sense
"And there will be no injection of undefined behaviour
^~~~~~~~~~~~~~~~~~~
conventional sense
- the undefined behaviour is already there if the asserted
constraints
^~~~~~~~~~~~~~~~~~~
altered sense
are not valid."
I still don't quite see your point. Perhaps I should have
said: In the
case where an asserted constraint is not met, the program is
invalid.
Being invalid it has undefined behaviour if it continues.
From another:
There is a difference between invalid and undefined: A program
is invalid
("buggy"), if it doesn't do what it's programmer intended,
while
"undefined" is a matter of the language specification. The
(wrong)
behaviour of an invalid program need not be undefined, and
often isn't in
practice.
I disagree with this characterization. Something can be buggy,
not doing
what the programmer intended, while also a perfectly valid
program. You
can make wrong logic that is valid/reasonable in the context of
the program.
Invalid in this case means the programmer has explicitly stated
certain
constraints must hold, and such constraints do not hold. So if
you
continue with the program in the face of invalid constraints,
you have no
guarantee what will happen - this is what I mean by 'undefined'.
You're using a nonstandard definition of undefined behavior.
Undefined behavior has a precise meaning, that's why Timon linked
the wiki article for you.
The regular definition of assert does not involve any undefined
behavior, only the newly proposed one.
