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

[Andrei Alexandrescu via Digitalmars-d]

On 12/13/16 8:07 PM, Chris M. wrote:
>
> Why not something like import foo.bar : baz or import foo : bar.baz to
> distinguish between module and symbol? It's already used anyway.
>
> Also I like Yuxuan's idea, the other ideas seem to add more clutter
> after the function name

So we have:

// 1
struct Buffer(R) if ((import std.range).isInputRange!R) { ... }

// 2
struct Buffer(R) if (import std.range:isInputRange!R) { ... }

// 3
@import("std.stdio") struct Buffer(R) if (isInputRange!R) { ... }

The first two require repeating the import for each separate 
declaration, e.g.:

// 1
bool equal(R1, R2)
if ((import std.range).isInputRange!R1 && (import 
std.range).isInputRange!R2)
{ ... }

// 2
bool equal(R1, R2)
if (import std.range:isInputRange!R1 && import std.range:isInputRange!R2)
{ ... }

The last is surprising because it uses a string where otherwise there 
would be an unquoted list of dot-separated names.

I prefer the current form of the proposal:

bool equal(R1, R2)
import (std.range)
if (isInputRange!R1 && isInputRange!R2)
{ ... }

The point has been brought up that the syntax import(std.range) is also 
used for string imports. It is a drawback.


Andrei