Good Morning Everyone,

I recently found myself wanting to introduce a bunch of member variables into the scope of the function I was currently working on.
Of course D has a nice way to do that; The with statement.

so

struct S { int x; }
int fn()
{
    S s;
    with(s)
    {
       x = 12;
       return x;
    }
}

this code works but it forces another level of indentation which makes it a little ugly.

So I did a small patch to my local version of dmd.
And now this works:

struct S { int x; }
int fn()
{
    S s;
    with(s):
    x = 12;
    return x;
}

It is a really simple patch and I think it's worthwhile to have this in the main language.

On Friday, 12 November 2021 at 10:55:21 UTC, Stefan Koch wrote:

struct S { int x; }
int fn()
{
    S s;
    with(s):
    x = 12;
    return x;
}

Note: this will actually create an invisible scope from with(x): towards the end of the parent scope.
but it shouldn't affect anything you might do.

I just wanted to point out that using x in the example above will not work it it's done before the with statement.
only after and similarly the names introduced by with will go out of scope when the parent scope leaves.

{
with(s):
 // only vaild for this scope
}
// s.x is not valid here anymore

On Friday, 12 November 2021 at 10:55:21 UTC, Stefan Koch wrote:

Good.

On Friday, 12 November 2021 at 10:55:21 UTC, Stefan Koch wrote:

How about other statements, like if, for, foreach, switch? When extending attribute: syntax to statements, might as well include all of them for consistency. N.b. this is already allowed in global scope:

static if (true):

Not in function scope though.

On Friday, 12 November 2021 at 11:05:54 UTC, Dennis wrote:

static if (true):

I am not proposing anything grand like that.
I don't think it has a very good fit for if or for
Since their scope tends to end before their parent block scope.

On Friday, 12 November 2021 at 11:05:54 UTC, Dennis wrote:

static if (true):

static if (true) should be banned from existence, use comments or delete if false.

On Friday, 12 November 2021 at 10:55:21 UTC, Stefan Koch wrote:

that's https://issues.dlang.org/show_bug.cgi?id=14332 BTW.

On Friday, 12 November 2021 at 10:55:21 UTC, Stefan Koch wrote:

struct S { int x; }
int fn()
{
    S s;
    with(s)
    {
       x = 12;
       return x;
    }
}

struct S { int x; }
int fn()
{
    S s;
    with(s):
    x = 12;
    return x;
}

I’m missing the point. Why using a struct to add some variables? At first I thought that you want to shadow already existing variables but this is prohibited in D and thank God for that.