DIP1027 + Design by Introspection

[Adam D. Ruppe]

On Tuesday, 2 February 2021 at 15:55:23 UTC, Daniel N wrote:
> Since DIP1027 is simpler than DIP1036

This is a myth, with the exception of the implicit to string 
conversion.

DIP 1027 had to break up the string and reconstruct a new one 
while reordering the tuple.

DIP 1036 is a direct syntax rewrite. It just splits the string on 
the ${ character into a tuple and puts a simple struct wrapper 
around the string parts so you can identify them. See for 
yourself how simple the diff is:

https://github.com/dlang/dmd/compare/master...adamdruppe:string_interp

The implicit to string part isn't implemented (gotta figure out 
how to express `alias toString this;` inside the compiler 
basically, it might be easy but I don't know how).


> Key insight, the function specifies what format it expects.
> printf(...)   @formatting!printf_style
> writefln(...) @formatting!writefln_style

DIP 1036 can do this as it is already written! You don't need a 
magic UDA, you just overload the function on the interp type as a 
library author.

Or you can simply call a function inside the interpolation thing 
if you want to do custom stuff as a user.