Re: [Vala] How to check if GLib.List is empty?

[Luca Bruno <lethalman88 gmail com>]

On 02/12/2014 16:03, Виталий Кирсанов wrote:
> Hello list.
>
> Probably there is a well-known answer to this but I failed to find it.
>
> Native C glib states that a null pointer GList is a valid list and it can
> be used as an argument to various list operations such as g_list_append().
> And to check whether the list is empty you need just to compare the head of
> the list with NULL;
>
> But it's not that straightforward with vala. If I write:
>
> var list = List<string>();
>
> then vala generates something like:
>
> GList * list = NULL;
>
>
> And after that I can call some of methods of list (e.g.
> list.append("hello");) but call to list.data would lead to a crash. That's
> a bit strange but ok, I understand that functions able to operate null data
> values like GList are not very well mapped to vala where this reference may
> not be null.
>
> The main question is when I have created list variable in vala, made some
> insertions and deletions how do I check whether it is empty or not?
> Probable answer would be I can call list.length(); method but it will not
> be efficient if, say, I call it on every iteration of a loop and the list
> is not empty.
>
> Is there a more simple and efficient way?
== null

:)