String format macros for ZZ

Add this to your zz.toml file:

[dependencies]
format = "*"

[repos]
format = "git://github.com/zzmodules/format"

using format

Creates a formatted string from a variety of special tokens with traditional printf style specifiers supported.

• {} - Treats argument like a struct, calling .display() for a char *
• {*} - Treats argument like a pointer to a struct, calling ->display() for a char *
• {0..9} - References argument by position. Treatment is the same as {}
• {*0..9} - References pointer argument by position. Treatment is same as {*}
• {$0..9} - References argument identifier name by position and uses it inline
• {0..9%X} - References argument by position with format. Treatment is like a limited printf

The @format::with() macro will treat struct and struct pointers specified with {}, {*}, and its variant as special input that should implement a displayable interface. Structs should simply implement a display() -> char * method like in the example below:

using format
using log
using string

struct Vector {
  float x;
  float y;
}

fn display(Vector *self) -> char * {
  new+64000 out = string::make();
  out.format("Vector { x: %0.2f, y: %0.2f }", self->x, self->y);
  return out.cstr();
}

fn main() -> {
  let vec = Vector { x: 1.23, y: 2.46 };
  log::info("%s", @format::with("{}", vec)); // Vector { x: 1.23, y: 2.46 }
  return 0;
}

MIT