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Effective Haskell: Chapter 1 “Creating New Variables”
@RebeccaSkinner
In the “Creating New Variables” section of Chapter 1, it says that you can’t reassign variables once defined. But new Haskellers might try things out in ghci and discover they can redefine a variable. It probably makes sense to point out that there’s some magic in ghci without explaining monads and do notation 
First Post!
RebeccaSkinner
Author of Effective Haskell
Great callout. I updated it and called it “a concession to usability”
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