Generating unique identifiers at compile time

[user1234]

On Thursday, 9 June 2022 at 21:20:27 UTC, JG wrote:
> Hi,
>
> As an experiment I have implemented the following kind of 
> pattern matching
> (by parsing the part of the string before '=').
>
> ```d
> struct S {
> int x;
> int y;
> }
>
> struct T {
>     int w;
>     S s;
> }
> void main()
> {
>     mixin(matchAssign(q{auto T(first,S(second,third)) = 
> T(1,S(2,3));}));
>     first.writeln;  // 1
>     second.writeln; // 2
>     third.writeln;  // 3
> }
> ```
> In doing so I wanted to produce unique identifiers (something 
> like gensym in racket.) I did this in a very hacky way:
>
> ```d
> auto hopefullyUniqueName(size_t n, size_t line=__LINE__) {
>     return 
> format!"____________________________var___________________________%s%s"(n,line);
> }
> ```
>
> where I pass in the hash of the right hand side in the 
> assignment in place of n.
>
> Is there some way to ask the compiler for a unique name or a 
> better way of achieving this?

No, for now there if there are other ways they are as hacky as 
yours.

The compiler usually uses a global counter to generate 
temporaries.
There's [been attempts] to expose it, exactly so that users can 
generate unique names, but that did not found its path in the 
compiler.

[been attempts]: https://github.com/dlang/dmd/pull/10131