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

[meppl via Digitalmars-d]

On Wednesday, 21 June 2017 at 12:05:55 UTC, Moritz Maxeiner wrote:
> On Wednesday, 21 June 2017 at 09:53:40 UTC, meppl wrote:
>> On Wednesday, 21 June 2017 at 09:27:20 UTC, MysticZach wrote:
>>> On Wednesday, 21 June 2017 at 08:15:34 UTC, MysticZach wrote:
>>>> On Wednesday, 21 June 2017 at 04:16:22 UTC, Moritz Maxeiner 
>>>> wrote:
>>>>> int myFunc(Args...)(Args args)
>>>>>   if (Args.length > 2)
>>>>>   in (args[0] != 0)
>>>>>   in (args[1] > 1)
>>>>>   out (result => result > 0) { ... }
>>
>> avoiding the "anonymous scope"-extra wouldnt hurt much?
>>
>> int myFunc(Args...)(Args args)
>>   if (Args.length > 2)
>>   in (args[0] != 0)
>>   in (args[1] > 1)
>>   out (result => result > 0)
>>   do { ... }
>
> Adding `if (...)` should not be different from adding `in 
> (...)` or `out (...)` in terms of syntax rules: it's 
> inconsistent. If you want to have that `do` there, I would 
> argue that it should also become required if only an `if (...)` 
> is present, so
>
> ---
>  int myFunc(Args...)(Args args)
>    if (Args.length > 2)
>    { ... }
> ---
>
> should then become illegal and must be rewritten as
>
> ---
>  int myFunc(Args...)(Args args)
>    if (Args.length > 2)
>    do { ... }
> ---
>
> I doubt that's going to happen, though (too much code 
> breakage), and I also don't like it. Simply drop the `do`.


yeah, i was probably not thinking too carefully about it. My idea 
was to keep the code readable, if the contracts are long. but as 
long as the "do" must appear behind a '}', everything is still 
fine, more or less.


	int myFunc1(Args...)(Args args)
	if (Args.length > 2)
	in
	{
		// much code
	}
	do
	{
		...
	}


	int myFunc2(Args...)(Args args)
	if (Args.length > 2)
	in
	{
		// much code
	}
	out (result => result > 0)
	{
		...
	}


both are readable, but one time we write `do` and the other time 
we dont. furthermore the second function body looks a little bit 
like belonging to "out". someone who is learning the D-language 
might get confused.