strLitAsString

fn strLitAsString(zg: *ZonGen, str_node: Ast.Node.Index) error{ OutOfMemory, BadString }!StringLiteralResult {
    if (!zg.options.parse_str_lits) return .{ .slice = .{ .start = 0, .len = 0 } };

    const gpa = zg.gpa;
    const string_bytes = &zg.string_bytes;
    const str_index: u32 = @intCast(zg.string_bytes.items.len);
    const size_hint = strLitSizeHint(zg.tree, str_node);
    try string_bytes.ensureUnusedCapacity(gpa, size_hint);
    const result = r: {
        var aw: Writer.Allocating = .fromArrayList(gpa, &zg.string_bytes);
        defer zg.string_bytes = aw.toArrayList();
        break :r parseStrLit(zg.tree, str_node, &aw.writer) catch |err| switch (err) {
            error.WriteFailed => return error.OutOfMemory,
        };
    };
    switch (result) {
        .success => {},
        .failure => |err| {
            const token = zg.tree.nodeMainToken(str_node);
            const raw_string = zg.tree.tokenSlice(token);
            try zg.lowerStrLitError(err, token, raw_string, 0);
            return error.BadString;
        },
    }
    const key: []const u8 = string_bytes.items[str_index..];
    if (std.mem.findScalar(u8, key, 0) != null) return .{ .slice = .{
        .start = str_index,
        .len = @intCast(key.len),
    } };
    const gop = try zg.string_table.getOrPutContextAdapted(
        gpa,
        key,
        StringIndexAdapter{ .bytes = string_bytes },
        StringIndexContext{ .bytes = string_bytes },
    );
    if (gop.found_existing) {
        string_bytes.shrinkRetainingCapacity(str_index);
        return .{ .nts = @fromBackingInt(@intCast(gop.key_ptr.*)) };
    }
    gop.key_ptr.* = str_index;
    try string_bytes.append(gpa, 0);
    return .{ .nts = @fromBackingInt(@intCast(str_index)) };
}