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A comment on Show HN: A lambda expression visualizer for the web. Parent comment

Re:Show HN: A lambda expression visualizer for the web by notb on Saturday February 16, 2013 @02:58AM (#5230833)
Agreed, it is unwieldy. However, because of it, eta-reduction is not as important because equivalent terms look the same, and name collisions can't happen. It made it a bit simpler.

And, that is definitely a bug, thanks. I think I could solve it by lazy evaluation (it wouldn't reduce that term) but I think I just need to correctly change vars when they move scope.

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Re:Show HN: A lambda expression visualizer for the web by Sniffnoy on Saturday February 16, 2013 @04:01AM (#5230949)
Not sure what you mean by "equivalent terms look the same". I'm not clear on how e.g. ##(2 1) and #1 look the same. Going by your remark about name collisions, I must ask if you are thinking of alpha-equivalence? (Which certainly is rendered unnecessary by the notational system.)

And thank you for making/hopefully fixing this!

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Re:Show HN: A lambda expression visualizer for the web by notb on Saturday February 16, 2013 @04:24AM (#5230997)
Oh I see. Yes I was thinking of alpha-equivalence, sorry.

Now I must ask, do you know any good papers/algos on that reduction? And how would you envision animating? It seems a bit like a lambda/var pair just fall off...

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Re:Show HN: A lambda expression visualizer for the web by Sniffnoy on Sunday February 17, 2013 @12:47AM (#5234330)
I don't know what I might refer you to. Beta reduction requires recognizing subtrees of the form (#T S) (where T and S are any subtrees), eta reduction just requires recognizing subtrees of the form #(T 1) (where T is any subtree).

No idea about animation. It's really not something I'd thought about, I have to say...

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Re:Show HN: A lambda expression visualizer for the web by Sniffnoy on Sunday February 17, 2013 @03:53AM (#5234633)
Oops -- I forgot about the non-freeness requirement. So not just any subtree. That makes it trickier. But still not hard, I think.
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