phone2word / phone2word.hs

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File phone2word.hs

 a digit, and children are stored in a Map where the key is the digit, so we know
 what digit each child node corresponds to by the path we have followed.
+Compared to using a simple Data.Map, this structure:
+- is about 10% slower to construct
+- takes 40% less time for lookups
+- uses about 75% of the memory
 data WordTree = Node { nodeSubForest :: !(Map.Map Char WordTree) -- children