DIP 1009--Improve Contract Usability--Preliminary Review Round 1

[Timon Gehr via Digitalmars-d]

On 23.06.2017 18:21, H. S. Teoh via Digitalmars-d wrote:
> On Fri, Jun 23, 2017 at 09:06:59AM +0000, Solomon E via Digitalmars-d wrote:
> [...]
>> T foo(T)(T x, T y)
>>      in (x > 0, y > 0)
>>      out (r; r > 0)
>> {
>>      return x % y + 1;
>> }
> 
> Hmm, I like this syntax for out-contracts!  It borrows from existing
> foreach syntax, so it has some precedence, whereas the previous proposal
> of `out(...)(...)` looks uglier and also looks deceptively like a
> template function declaration.
> 
> `out (r; r > 0)` gets my vote.
> 
> 
> OTOH, I don't like the comma in the in-contract.  Let's just keep it as
> either separate clauses:
> 
> 	in (x > 0)
> 	in (y > 0)
> 
> or just use a boolean operator:
> 
> 	in (x > 0 && y > 0)
> 
> 
> T
> 

Agreed. Implementation:
https://github.com/dlang/dmd/compare/master...tgehr:contract-syntax

(At most one contract of each type is supported. It is not very hard to 
implement multiple contracts, but this requires touching semantic analysis.)