Re: [review] [text] Text review begins June 11

From: Gavin Lambert (boost_at_[hidden])
Date: 2020-06-03 08:06:16

On 3/06/2020 18:22, Emil Dotchevski wrote:
> Therefore, the documentation can just specify that a rope is as thread-safe as an int.

I strongly dislike the phrase "as thread-safe as an int" because it's 
often applied to structures containing more than one pointer-size member 
(eg. shared_ptr), and there are architectures (notably x86) where an int 
is considerably more thread-safe than this could be, because they have a 
(architecture, not language) guarantee of coherence lacking in larger 
values (or in multi-member structs regardless of size).  (Granted, 
portable code cannot assume pointer-size values are coherent, but often 
a given architecture can be assumed.)

I don't recall where intrusive_ptr (the core of rope) falls on this 
spectrum; it is using an atomic refcount but there's still the separate 
operations of copying the pointer and updating the refcount.  I think 
it's safe if done in the correct order, however; but not otherwise.

> The grammar seems wrong here; 'I don't know if you've ever written an 
> undo system that can do, undo, or redo any command you can think of, in 
> less than 40 lines of code, but there one is."

It sounds correct to me; however it probably would be slightly better to 
put "in less than 40 lines of code" in parentheses or dashes rather than 
comma clauses.