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![Basile B.'s Gravatar profile Gravatar of Basile B.](//www.gravatar.com/avatar/9dbc5c130e432d1f34b32a7d6dd6c41b?d=identicon&s=32) | Posted by Basile B. in reply to Quirin Schroll | Permalink Reply |
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Basile B. ![Basile B.'s Gravatar profile Gravatar of Basile B.](//www.gravatar.com/avatar/9dbc5c130e432d1f34b32a7d6dd6c41b?d=identicon&s=80)
Posted in reply to Quirin Schroll
| On Thursday, 25 July 2024 at 14:30:31 UTC, Quirin Schroll wrote:
> On Wednesday, 24 July 2024 at 20:17:21 UTC, Basile B. wrote:
> On Wednesday, 24 July 2024 at 11:57:35 UTC, Quirin Schroll wrote:
> Mixins can produce types, expressions, statements, and declarations. That is great, but it could be better.
Why not allow mixin identifiers, storage classes, attributes, etc.?
Contrived example:
struct mixin("C")
{
mixin("const"):
void f(mixin("ref") int x) mixin("@safe") { }
}
There’s no good reason a whole entity must be written in a string literal with a “hole” to be filled by format just because its name is generated. Interpolated strings help, but are not fundamentally different.
There is a good reason for that, that is not what is explained in one of the answer I can read. Mixins must introduce full grammatical constructs, i.e an expression, a statement, or a declaration, so that the content can be passed to the parser. Also they cant interfere with a scope. There's a well known bug (closed as of today), mixin("private:") .
I think you missed the point. What counts as a whole grammatical construct? Types can be mixed in, after all… So, at this point, calling types, expressions, statements, and declarations “whole,” but others which have names in the D grammar not is just arbitrary. Now, mixin("private:") isn’t illegal, it just doesn’t do anything useful. Why can’t identifiers, storage classes, attributes, etc. not count as whole entities?
I dont know how to this explain this better but let's try. The AST is essentially made of 4 great family of nodes, Statements, Expressions, Declarations and Types.
Those are easy to insert dynamically. That's all. I did not say that partial construct could not be mixed-in, rather that this seems complicated at first glance.
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