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Discussion on: Understanding the Fold Operation

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yawaramin profile image
Yawar Amin

Thanks for this very clear explanation. Do you remember the old days of Elm when it was FRP and there was a (I think) Signal.foldp function that was explained as 'returning a new state by folding over the past state and an event'? The theory behind folding is so generally applicable, it's quite fascinating.

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Kasey Speakman Author

I was hoping someone would notice the similarity with MVU. :) In fact, I always found folds confusing until I realized that an Elm application (even today) is just a fold. (And the view function is a transformation run on the model after each fold step.) And so, adopting the same strategy used by MVU enables a straight-forward definition of fold.

Thanks for the comment!