Re: scope guard question

2020-07-01 Thread Simen Kjærås via Digitalmars-d-learn
On Tuesday, 30 June 2020 at 12:18:14 UTC, Steven Schveighoffer 
wrote:
I can see where it would be confusing, and it could probably 
contain an example and clarification.


https://issues.dlang.org/show_bug.cgi?id=20997


Re: scope guard question

2020-06-30 Thread Arjan via Digitalmars-d-learn
On Tuesday, 30 June 2020 at 12:18:14 UTC, Steven Schveighoffer 
wrote:

On 6/30/20 2:56 AM, Arjan wrote:
On Monday, 29 June 2020 at 22:47:16 UTC, Steven Schveighoffer 
wrote:

[...]


Thanks for the assurance. The spec does state it like this:
```
The ScopeGuardStatement executes NonEmptyOrScopeBlockStatement 
at the close of the current scope, rather than at the point 
where the ScopeGuardStatement appears.

```
Which is correct, but there is no single example with a return 
where the ScopeBlockStatement interferes with the return.


I started wondering about this since I hit a bug in a piece of 
code.


I can see where it would be confusing, and it could probably 
contain an example and clarification.


-steve


That would certainly be helpfull.


Re: scope guard question

2020-06-30 Thread Steven Schveighoffer via Digitalmars-d-learn

On 6/30/20 2:56 AM, Arjan wrote:

On Monday, 29 June 2020 at 22:47:16 UTC, Steven Schveighoffer wrote:
Yes. The return statement is inside the scope of the function, so it 
runs before the scope is exited. Are you saying the spec doesn't say 
that?


Thanks for the assurance. The spec does state it like this:
```
The ScopeGuardStatement executes NonEmptyOrScopeBlockStatement at the 
close of the current scope, rather than at the point where the 
ScopeGuardStatement appears.

```
Which is correct, but there is no single example with a return where the 
ScopeBlockStatement interferes with the return.


I started wondering about this since I hit a bug in a piece of code.


I can see where it would be confusing, and it could probably contain an 
example and clarification.


-steve


Re: scope guard question

2020-06-30 Thread Arjan via Digitalmars-d-learn
On Monday, 29 June 2020 at 22:47:16 UTC, Steven Schveighoffer 
wrote:
Yes. The return statement is inside the scope of the function, 
so it runs before the scope is exited. Are you saying the spec 
doesn't say that?


Thanks for the assurance. The spec does state it like this:
```
The ScopeGuardStatement executes NonEmptyOrScopeBlockStatement at 
the close of the current scope, rather than at the point where 
the ScopeGuardStatement appears.

```
Which is correct, but there is no single example with a return 
where the ScopeBlockStatement interferes with the return.


I started wondering about this since I hit a bug in a piece of 
code.


Re: scope guard question

2020-06-29 Thread Stanislav Blinov via Digitalmars-d-learn

On Monday, 29 June 2020 at 22:31:12 UTC, Arjan wrote:

So when no inner scope is present, the scope exit 'runs' after 
the return? Is that indeed expected behavior according to the 
specification?


Yes. A scope ends at the '}'. Destructors and scope guards 
execute then, after the return.


Re: scope guard question

2020-06-29 Thread Steven Schveighoffer via Digitalmars-d-learn

On 6/29/20 6:31 PM, Arjan wrote:

```
void main()
{
   import std.stdio;
   auto f = (){
     string[] t;
     { // inner scope
   t ~= "hello";
   scope( exit ) t ~= "world";
     } // inner scope exit
     return t;
   };

   f().writeln; // ["hello", "world"]
}
```
removing the inner scope in f() gives ["hello"]

So when no inner scope is present, the scope exit 'runs' after the 
return? Is that indeed expected behavior according to the specification?


Yes. The return statement is inside the scope of the function, so it 
runs before the scope is exited. Are you saying the spec doesn't say that?


-Steve