Yog Script (.ys, .yns) analyzed: its lexer, parser and syntax tree, names resolved, the class index model — what the build and the editors read a source with.
namespace System.Meta;
/// Marks a method as a function-like macro: `Name!(…)` runs it on the
/// call's text (`string Name(string input)`), and the code it gives takes
/// the call's place.
public sealed class ProcMacro : Attribute {}