you know, there's also a per-post-order visit of a tree in order to transform it and that lacks an example too 😕

it's the paragraph preceding the one I linked


@AbbieNormal There is an sxml port to Racket, and it actually has examples in its documentation!…


I took a look

Admittedly the example usage of pre-post-order is enlightning

As far as I understand racket has no foldts

I wonder if some other scheme could have any more axamples

Like Chicken, for example

@AbbieNormal Reading Wingo's paper now.

Discovered that Racket does have foldts ... specifically for rackunit test suites. 😀…
@AbbieNormal foldt has a map in it. A transducet could use list-transduce+rcons instead of map for calling itself, and could take only one transducer where the 2-arity call represents fhere and the 1-arity call represents fup.

This is an example where separating the transducer and the reducing function is clearly a useful thing, as they would be applied anew on each subtree.

@AbbieNormal @veer66 foldts has an internal reduce (fold) already, and fhere suddenly becomes the 2-arity case of the transducer.

fdown is a new thing that seeds the reducer, and fup is in a really complicated situation where it holds the partial future, the present and the past.

Maybe fhere can be a transducer and fdown and fup separate things, but I'll have to finish the paper and turn my brain inside-out for a bit to understand what these things are used for.

@clacke @veer66

I couldn't read the paper

In these days I can't go to the print shop I used to go to

And I only have a 15 inches monitor

My plan is to collect all the code in a folder and test it in a REPL, while I read

I should have done it today but I got distracted 😕

@clacke @veer66

what can I say ?

I can't read it on the monitor

I need to finger point diverse scraps of code as I read

Probably I even need to test drive fragments of code at the REPL


@AbbieNormal @veer66 Sorry, I didn't mean it like that, I was just sharing in the challenges accessing things. The family was using the computers, so I was limited to my phone.

I haven't finished the paper yet, read up until foldts was introduced, which I guess was halfway.

@clacke @veer66

I appreciate your concern, thanks ! 😊

No offense taken !

I'm having a hard time in foguring out the "second order traversal" made with pre-post-order

So I'm writing a file with some notes made of svg scraps, and scheme scraps so that I can copy and paste in the REPL to figure things out

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