3 ms·

Thanks for looking into that, Matt. It has been a long time since I did any real C programming, and I could not believe that they would be passing by value for

• riffraff 12y ago
  it's not, really, VALUE may alternatively contain an immediate value or a pointer, i.e. a couple bits are used for type tagging and the rest is used to hold an int/float/nil/boolean. and avoid an extra struct.
• stormbrew 12y ago
  It is uintptr_t in size, but it's actually a bit more complicated than that. If the 'value' is a fixnum, the low bit is set to 1 and the bottom 31 or 63 bits of the integer are shifted to the left and stored directly in the VALUE [1]. And then there's a few other bit patterns (all with the low bit set to zero) that also mean embedded values [2], including symbols, where they're actually an index into a string table rather than an actual object pointer. So a lot of the time, VALUE is anything but a misnomer. Also, the name for this pattern is tagged pointer. It's one of the most notable things ruby borrowed from emacs lisp [3]. Also, the entire point of symbols is that they don't need to be dereferenced (or strcmp'd) to compare them. That's not the slow part of symbol comparison. [1] https://github.com/ruby/ruby/blob/trunk/include/ruby/ruby.h#L234 https://github.com/ruby/ruby/blob/trunk/include/ruby/ruby.h#... [2] https://github.com/ruby/ruby/blob/trunk/include/ruby/ruby.h#L383 https://github.com/ruby/ruby/blob/trunk/include/ruby/ruby.h#... [3] https://www.gnu.org/software/emacs/manual/html_node/elisp/Object-Internals.html https://www.gnu.org/software/emacs/manual/html_node/elisp/Ob...