[luatex] robustness of node.traverse

[Taco hoekwater]

Hi,

Op 9 nov. 2012 om 20:19 heeft Stephan Hennig <mailing_list at arcor.de> het volgende geschreven:

> Am 09.11.2012 09:58, schrieb Taco Hoekwater:

> What is the advantage of this to the naive
> 
>  local n = head
>  while n do
>    ...
>    n = n.next
>  end
> 
> ?

Not a lot, but some people prefer the writing style with for loops. Running speed
is comparable for both styles of looping, if I recall correctly. 

> 
>  a guard missing in the while loop that stops when t == nil.
> 

It is in the code, of course. The explanation was getting long, so I skipped that.

> |     return t
> |   end
> | \stoptyping
> 
> Again, what is the advantage of this to the naive
> 
>  local n = head
>  while n do
>    if n.id == <id> then
>      ...
>    end
>    n = n.next
>  end


traverse_id really is faster, because the internal lookups are much faster than the repeated node.id and node.next calls. But still, it is mostly about style.

Best wishes,
Taco