Re: Lua strings as "atoms"???

[Rici Lake <lua@...>]

On 16-May-05, at 11:28 PM, Chris Marrin wrote:

> Ok, so maybe they were thinking about the now defunct generational 
> collector. At any rate, is there any officially sanctioned way of 
> handling "atoms" or the equivalent?

There is no officially sanctioned way of exporting internal 
information. I guess that's the sad answer. Although the workarounds 
are not generally awful.

In any event, I can imagine implementations of Lua which would have 
precisely the property suggested by the refman with respect to strings. 
For example, a short string (for some definition of short) might be 
stored directly in the stack slot. With a bit of careful rearrangement, 
you could fit 11-15 characters in a stack slot (depending on what the 
minimum alignment of a pointer is on your 64-bit architecture, if any). 
That might significantly reduce contention on the string table, 
particularly as the aforementioned 64 bit architecture is likely to be 
able to do a 16-byte aligned comparison fairly rapidly. In fact, I've 
been tempted to try that.

> What would upvalues be replaced with? Surely Lua is not abandoning 
> closures! That is one thing that has gotten Lua a lot of press for 
> being hip and cutting edge :-)

Function environments, apparently, now that CFunctions also have them. 
I don't believe that Lua will abandon closures, but CFunction upvalues 
might be regarded as a holdover.

R.