On 10 Jul., 15:19, Bart Kastermans <[EMAIL PROTECTED]> wrote:
> I am playing with some trees. In one of the procedures I wrote
> for this I am trying to change self to a different tree. A tree
> here has four members (val/type/left/right). I found that self = SS
> does not work; I have to write self.val = SS.val and the same for
> the other members (as shown below). Is there a better way to do this?
>
> In the below self is part of a parse tree, F is the parse tree of a
> function f with argument x. If a node in the parse tree is labelled
> f, we should replace it by the parse tree for the function f, F, with
> the remainder of the tree substituted for the input variable for the
> function f, here x.
>
> def elimF (self):
> if self.val == "f":
> SS = F.copy ()
> SS.subst ('x', self.left)
> self.val = SS.val # from here: set self to be SS
> self.type = SS.type
> self.left = SS.left
> self.right = SS.right # completed: set self to be SS
>
> if self.left != None: # iterate onward, inf recursion if f
> # appears. Would need a check in
> # real version
> self.left.elimF ()
> if self.right != None:
> self.right.elimF ()
>
> Best,
> Bart
Since it is acting on a tree why doesn't the code substitute self in
its parent by SS? That's the natural perspective if one considers a
tree as a linked structure and inserts and deletes nodes within this
structure.
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