[Haskell-beginners] The Holy Trinity of Functional Programming
Costello, Roger L.
costello at mitre.org
Wed Aug 22 13:38:01 CEST 2012
> But do you think you could provide a
> more "real world" example of an application
> of the "Holy Trinity" ideas?
A commonly cited real-world example that illustrates the first key idea (recursive data type) is a binary tree:
data Tree = Node String Tree Tree | Leaf
The elements of this data type include:
Node "Root" Leaf Leaf
Node "Root" (Node "Left" Leaf Leaf)
(Node "Right" Leaf Leaf)
And so forth.
Common functions on this data type include insertions, deletions, traversal.
I am not sure if there is a use for the infinite value of this data type.
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