DIP10005: Dependency-Carrying Declarations is now available for community feedback

[Andrei Alexandrescu via Digitalmars-d]

On 12/15/2016 02:22 PM, Timothee Cour via Digitalmars-d wrote:
> Some more details on my proposa based on UDA:
>
> // applies to next decl
> @deps!({import std.algorithm;})
> void test1(){}
>
> // applies to a set of decls
> @deps!({import std.stdio;}){
>   void test2(){}
>   void test3(){}
> }
>
> // applies to all following decls (':')
> @deps!({import std.array;}):
>
> // can specify other dependencies beyond imports and have arbitrary
> complex logic:
> @deps!({
>   import std.range;
>   static int[100] data2;
>   version(linux){
>     enum data1=import("foo");//string import
>     pragma(lib, "curl");
>   }
> }):
> void test4(){}
>
> // Can alias some dependencies:
> alias deps1=deps!({import std.algorithm;});
>
> @deps1
> void test4(){}
>
> NOTE: the above code compiles if we add
> `struct deps(T...){}`, but that logic would be implemented in the compiler.

I now understand the idea, thank you.

My question is, doesn't this take things too far? Earlier I wrote:

> The acceptability of the proposal decays exponentially with its
> deviation from existing import syntax.

Indeed adding less syntax is better, but that's not an absolute; the 
optimum isn't necessarily at the "zero syntax added" point. This is 
because there are several things to harmonize in language design, which 
naturally are in tension.


Andrei