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Is there anywhere to test / document what the Haskell Evaluation / Apply sequence is for a code snippet?

I'm wondering if an online tester for 'apply' exists, or maybe I just need to call the right function in Haskell to make visible the parse tree, given an input string? It seems like there surely should be a tool but I don't know how to find it?

I'm asking this while reading Graham Hutton's Programming Haskell book and realizing that I do not actually understand 'apply' sequences, eg the definition of redex, Haskell: Alternative, non-circular definition of Redex?

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AnneTheAgile
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  • Not sure why this is voted to close? It seems like a simple, clear question? – AnneTheAgile Dec 23 '14 at 19:56
  • It's off-topic despite being simple and clear. The ban on recommendation questions trumps the general "on topic" rule; see the [help center](http://stackoverflow.com/help/on-topic). You're specifically asking someone to "recommend or find... a tool." You can ask on Meta if you disagree with the close votes or want more discussion. – Christian Conkle Dec 25 '14 at 01:26
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    Oh, sorry, there's a little bit more going on in this question that's worth addressing. You can see how GHC *evaluates* a given *value* using the `:sprint` and `:force` commands in ghci. There's probably an existing question on that point. – Christian Conkle Dec 25 '14 at 01:31
  • @ChristianConkle, ok I will research those commands. I am not sure such a tool even exists. So are you saying that asking about the existence of a tool is verboten? – AnneTheAgile Dec 26 '14 at 19:27
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    I don't know about "verboten." My understanding of SO policy is that asking about the existence of a tool is off-topic. How the rule applies, and precisely what the rationale is, isn't totally clear to me, particularly in a smaller tag like [haskell]. The folks on Meta could probably help. (By the way, one tool to look into is [`ghc-vis`](https://hackage.haskell.org/package/ghc-vis).) – Christian Conkle Dec 26 '14 at 20:19

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