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Today's Topics:
1. Rose tree (mike h)
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Message: 1
Date: Sun, 8 Jan 2017 20:06:33 +0000
From: mike h <mike_k_hough...@yahoo.co.uk>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <beginners@haskell.org>
Subject: [Haskell-beginners] Rose tree
Message-ID: <adec9332-6f04-4c0b-8c27-a0f421283...@yahoo.co.uk>
Content-Type: text/plain; charset=utf-8
Hi,
I’m rapidly descending into a spiral of confusion! :)
How do I add something to a rose tree?
I have
data Tree a = Node a [Tree a] deriving (Show)
add :: Eq a => a -> a -> Tree a -> Tree a
and the first ‘a’ is the thing to add and the second is its parent node.
i.e.
add :: Eq a => a -> a -> Tree a -> Tree a
add x px (Node x' []) = Node x' [Node x []]
…..
I’ve tried various ways for the more general case but always seem to lose part
of the tree.
Any advice would be very welcome.
Thanks
Mike
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