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rewrite-clj 2024-09-09
for splint's rewriting, i am doing a fancy postwalk over a zipper. i want to not check forms that are quoted, so '(+ 1 x) should be skipped. using zip/next will move the zipper into the quoted forms. using zip/right only works when the quoted form isn't the final object in the enclosing form (`[foo 'bar baz]` works but [foo 'bar] doesn't). given that i could be nested arbitrarily deep, how do i go to the "next" form that would be found by calling zip/next at the end of the quoted form?
for example, given string input "(ns hello) [['(+ 1 x)]] ending":
:form (ns hello) :quote? false :right <vector: [['(+ 1 x)]]> :next <token: ns>
:form ns :quote? false :right <token: hello> :next <token: hello>
:form hello :quote? false :right nil :next <vector: [['(+ 1 x)]]>
:form [[(quote (+ 1 x))]] :quote? false :right <token: ending> :next <vector: ['(+ 1 x)]>
:form [(quote (+ 1 x))] :quote? false :right nil :next <quote: '(+ 1 x)>
:form (quote (+ 1 x)) :quote? true :right nil :next <list: (+ 1 x)>
:form (+ 1 x) :quote? false :right nil :next <token: +>
:form + :quote? false :right <token: 1> :next <token: 1>
:form 1 :quote? false :right <token: x> :next <token: x>
:form x :quote? false :right nil :next <token: ending>
:form ending :quote? false :right nil :next <token: ending>right and get out, but calling next will keep you inside of the quoted formso if you see a quoted form, you call right, and then if it's nil, how do you go to the next outer form?
Calling zip/up doesn't work because you could be arbitrarily deep
do you call up in a loop until right returns non-nil?
looks like you can call (-> zloc next next rightmost next) to escape lol
;; given `(ns hello) [['(+ 1 x)]] ending`:
(-> zloc ;;
zip/next ;;
zip/rightmost ;;
zip/next ;;
) oh dang, next is implemented as calling up in a loop until right returns non-nil
hmm that doesn't generalize, so i do have to use
(loop [p zloc]
(if-let [loc (zip/up p)]
(or (zip/right loc)
(recur loc))
(assoc p :end? true)))
Heya, I've got to run some errands but I will check in later. Are you still stuck and wanting help?
no, but knowing a built-in solution would be helpful
I did some thinking about skipping nodes a while back https://github.com/clj-commons/rewrite-clj/discussions/199. When I started experimenting with some code I realized a generic solution is a bit tricky.
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