[Gtk2hs-users] What are column IDs for?

[Wolfgang J. <g9k...@ac...>]

Hello,

as far as I understand, a tree model contains a forest whose nodes are marked 
with data of an arbitrary type. For example, there is the type ListStore a 
where the “a” can be any type. So there is no notion of column in tree 
models. Columns belong to a view and the values shown in a column are 
determined by applying some function to the one-and-only value at the 
respective row in the model.

Now, I don’t understand why treeModelGetValue takes a ColumnId argument. I 
would expect it to just take a tree model and a tree iterator and return the 
one-and-only value at the respective row.

Could someone please explain?

Best wishes,
Wolfgang