#Implementing trees#
-In [[Assignment3]] we proposed a very ad-hoc-ish implementation of trees.
+In [[Assignment3]] we proposed a very ad-hoc-ish implementation of
+trees. It had the virtue of constructing trees entirely out of lists,
+which meant that there was no need to define any special
+tree-construction functions.
Think about how you'd implement them in a more principled way. You could
use any of the version 1 -- version 5 implementation of lists as a model.
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-Linguists often use trees of this sort. The inner, non-leaf nodes of the
+The inner, non-leaf nodes of the
tree do have associated values. But what values they are can be determined from
the structure of the tree and the values of the node's left and right children.
So the inner node doesn't need its own independent label.