How to avoid throwing an exceptions for a built-in function?

[Nicholas Wilson via Digitalmars-d-learn]

On Wednesday, 10 May 2017 at 12:40:41 UTC, k-five wrote:
> I have a line of code that uses "to" function in std.conv for a 
> purpose like:
>
> int index = to!int( user_apply[ 4 ] ); // string to int
>
> When the user_apply[ 4 ] has value, there is no problem; but 
> when it is empty: ""
> it throws an ConvException exception and I want to avoid this 
> exception.
>
> currently I have to use a dummy catch:
> try{
>     index = to!int( user_apply[ 4 ] );
> } catch( ConvException conv_error ){
>     // nothing
> }
>
> I no need to handle that, so is there any way to prevent this 
> exception?

there has been talk of adding an overload that substitutes a 
supplied value on failure.
apart from that there is assumeWontThrow in the stdlib somewhere.