008 comprehension rows vec3

// RED PIN (type-system design walk, 2026-07-06/07). The vector
// question that opened the walk: "can you EASILY parameterize the
// dimensions of a vector?" A comprehension row over a comptime RANGE
// generates fields — the table-comprehension domain (`over 0..3`,
// shipped for value tables in 310_092) lifted to the type layer. N is
// an ordinary comptime value; a config file or a schema could supply
// it. Field-naming projection spelling PROVISIONAL (`v{i}` -> v0, v1,
// v2 — upper-exclusive range per the table.kz convention).

~import std/types
~import std/io

const std = @import("std");

~std/types:struct(Vec3) {
    i over 0..3 -> v{i}: f64
}

~event main {}

~proc main|zig {
    const p = Vec3{ .v0 = 1.0, .v1 = 2.0, .v2 = 3.0 };
    std.debug.print("({d:.1}, {d:.1}, {d:.1})\n", .{ p.v0, p.v1, p.v2 });
}

~main()