request switch statement with common block

[Andre Artus]

On Monday, 5 August 2013 at 06:28:12 UTC, luminousone wrote:
> perhaps a more generic solution should be looked at, extend 
> contracts to work with all scope blocks.
>
> switch(somenumber)
> in {
>     ... before stuff ...
> }
> out {
>     .... after stuff ...
> }
> body {
>     case 1:
>     in {
>        ... etc ....
>     }
>     out {
>        ... more etc ...
>     }
>     body {
>        ...
>     }
>     case 2:
>       // and so on
> }
>
> or perhaps
>
> for( int i = 0 ; i < 10 ; i ++ )
> in {
>     assert( i == 0 );
> }
> out {
>     assert( i == 9 );
> }
> body {
>    ... stuff ...
> }
>
> if it is desired for a particular contract block to be called 
> in release builds perhaps a attribute label to mark it as a 
> runtime block or something similar.
>
> foreach( i, k ; somerange )
> @runtime in {
>  ...
> }
> body {
> }

Please do not take offense, but I do not see this as a good idea. 
Contracts have a very different function; not just in D, but 
every language that uses them. The idea is to support 
design-by-contract programming. Overloading the constructs for 
the purposes proposed here would, in my opinion, cause confusion 
and/or weaken the proper use of contract programming.


The code in the contract conditions should never do anything more 
than what is necessary to specify the contract. It should not do 
explicit IO (other than implied by assert()), mutate state, or 
anything like that.

At the bottom of this page you can find a reading list for more 
info.
http://www.digitalmars.com/d/dbc.html

Or for a general overview:
http://en.wikipedia.org/wiki/Design_by_contract

Walter, does the D compiler or any of it's companion tools do any 
static analysis on the contracts? Such as a void safety/null 
reference check?