Re: Do strings move around?

[Roberto Ierusalimschy <roberto@...>]

> >>>>> "Roberto" == Roberto Ierusalimschy <roberto@inf.puc-rio.br> writes:
> 
>  >> What about strings accessed via upvalue pseudo-indexes?
> 
>  Roberto> They should be valid while the corresponding call is active.
>  Roberto> Documenting it is in my "todo" list.
> 
> So here's a more tricky case: what if you do lua_tostring on some stack
> index, and then move that stack item while keeping it on the stack (i.e.
> with lua_rotate or one of its many derivatives such as lua_remove)?

The new wording in the manual already covers this case:

    When the index is a stack index,
    Lua guarantees that the pointer returned by @id{lua_tolstring}
    is valid while the value at that index is neither modified nor popped.
    When the index is a pseudo-index (an upvalue),
    the pointer returned by @id{lua_tolstring}
    is valid while the corresponding call is active and
    the corresponding upvalue is not modified.

-- Roberto