Howdy,
Since Lua is a language that provides basic mechanisms instead of builtin high-level constructs, I am wondering: why were to-be-closed variables given special language-level support? I think it should be possible to implement the equivalent using closures:
| do
| local x<close> = CloseMe1()
| local y<close> = CloseMe2()
| print( x, y )
| return 5
| end
can be implemented as e.g.:
| return with( CloseMe1(), function( y )
| return with( CloseMe2(), function( x )
| print( x, y )
| return 5
| end)
| end)
where:
| function with(expr, func)
| ... = pcall(func, expr)
| getmetatable(expr).__close(expr)
| -- propagate errors and/or return result
| ...
| end
I left out some details, but I'm assuming that something like the above could be made to work. If not, what am I missing? But either way, I am wondering what went into the decision to give to-be-closed variables language-level support instead of having users construct them from Lua's mechanisms?
I like the feature and I use it, but I am just wondering out of curiosity.
Thanks
David
