printError

    pub fn printError(self: Token, gpa: Allocator, list: *std.ArrayList(u8)) error{OutOfMemory}!void {
        switch (self) {
            .target, .target_must_resolve, .prereq, .prereq_must_resolve => unreachable, // not an error
            .incomplete_quoted_prerequisite,
            .incomplete_target,
            => |index_and_bytes| {
                try list.print(gpa, "{s} '", .{self.errStr()});
                if (self == .incomplete_target) {
                    const tmp = Token{ .target_must_resolve = index_and_bytes.bytes };
                    try tmp.resolve(gpa, list);
                } else {
                    try printCharValues(gpa, list, index_and_bytes.bytes);
                }
                try list.print(gpa, "' at position {d}", .{index_and_bytes.index});
            },
            .invalid_target,
            .bad_target_escape,
            .expected_dollar_sign,
            .continuation_eol,
            .incomplete_escape,
            .expected_colon,
            => |index_and_char| {
                try list.appendSlice(gpa, "illegal char ");
                try printUnderstandableChar(gpa, list, index_and_char.char);
                try list.print(gpa, " at position {d}: {s}", .{ index_and_char.index, self.errStr() });
            },
        }
    }