user defined no bounds check

[monarch_dodra]

On Monday, 20 August 2012 at 09:58:54 UTC, Jonathan M Davis wrote:
>
> I'm not sure that it was ever even considered that the 
> programmer might want
> to do something special with them. assert is affected by 
> -release, and -
> noboundscheck was added later for extra control. They had 
> nothing to do with
> the programmer doing anything in their code. I have no idea how 
> Walter would
> feel about adding noboundscheck and/or release versions which 
> correspond to
> the flags.
>
> But since it's generally bad practice to make code differ 
> between non-release
> mode and release mode, and assert already gives you the ability 
> to have checks
> that which are around in non-release but not in release, I 
> don't know that it
> really buys you much to add such version identifiers.
>
> - Jonathan M Davis

C++ uses "ifdef debug" a lot, so I guess it is confusing at 
first, but "assert" can indeed get the same done (worst case 
scenario, it can call a function with side effects that always 
returns true). There is no equivalent for "ifndef debug", but I 
agree that is bad.

Regarding "noboundscheck" I was thinking in particular about 
Container.Array, or any other range in general. If the user 
compiles using noboundscheck, then one can only assume the user 
does not want for Container.Array.Range to check its own bounds 
either.

Andrei says something in his book along the lines of "If a built 
in can do it, so should a user defined type" (don't have the 
quote here though, sorry). So basically, if a built in array can 
conditionally control bounds checking, why can't a user defined 
range do it?