Overhead of DIP1036

[Timon Gehr]

On 1/9/24 20:05, Walter Bright wrote:
> On 1/9/2024 12:45 AM, Alexandru Ermicioi wrote:
>> If that's the case, then 1036 wins imho, by simple thing of not doing 
>> any parsing of format string.
> 
> Consider the overhead 1036 has by comparing it with plain writeln or 
> writefln:
> 
> ```
> void test(int baz)
> {
>      writeln(i"$(baz + 4)");
>      writeln(baz + 5);
>      writefln("%d", baz + 6);
> }
> ```
> 
> ...

I think Alexandru and Nickolay already discharged the concerns about 
overhead pretty well, but just note that with DIP1027, `test(3)` prints:

%s7
8
9

There is fundamentally no way to make this work correctly, due to how 
DIP1027 throws away the information about the format string.

With DIP1036e, `test(3)` prints:

7
8
9

And you can get rid of the runtime overhead by adding a `pragma(inline, 
true)` `writeln` overload. (I guess with DMD that will still bloat the 
executable, but I think other compiler backends and linkers can be made 
elide such symbols completely.)