Re: To-Be-Closed For-In-Loop Variable has Problems with Tailcalls

[Xmilia Hermit <xmilia.hermit@...>]

On 31.03.2021 at 23:14 Gé Weijers wrote:

The problem is that 'tail' is no longer a tail call. In the general case the file can only be closed after 'tail' returns, like in this convoluted example:

    Correct me if I'm wrong but at
    https://github.com/lua/lua/blob/master/lparser.c#L1814 the tailcall
    is inserted. For that fs->bl->insidetbc needs to be zero. It
    is set at https://github.com/lua/lua/blob/master/lparser.c#L1710 in
    checktoclose called from localstat but not in the for loop case at
    https://github.com/lua/lua/blob/master/lparser.c#L1602. In for loop
    case the fs->bl->insidetbc is never set and therfore the call
    is a tailcall.
    
    Second, could you explain why commenting `return tail()` out in my
    previous example yields
    > ./lua test.lua 
    This should be called
    
    while the output with the `return tail()` is
    > ./lua test.lua 
    Why is this called?
    
    shouldn't they be the same?
    
    Regards,
    Xmilia