Edit Question - KnowledgeHub

Title Body

Given the following tree (or any other form in Clojure including maps and vectors): '( (a b) (c d) ) I would like to generate a map in Clojure that indexes each sub-form according to a depth-first traversal of the entire form and also provides a vector (or list) of the indices of the form's children (if any). 0 -> a [] 1 -> b [] 2 -> (a b) [0 1] 3 -> c [] 4 -> d [] 5 -> (c d) [3 4] 6 -> ( (a b) (c d) ) [2 5] I have so far only managed to use clojure.walk to produce the first part (indexing the subforms) but I am baffled as to how to generate the indices of the children as well. My code is appended at the end and produces: user=> (depthFirstIndexing '( (a b) (c d) )) {6 ((a b) (c d)), 5 (c d), 4 d, 3 c, 2 (a b), 1 b, 0 a} So the indexes to the sub-forms are generated correctly according to depth-first traversal but I don't see how I can obtain the indices of the children of every sub-form. I tried to use the zippers module but I couldn't see how to perform a depth-first traversal to collect the indices. half-way there code (use 'clojure.walk) (defn depthFirstIndexing [aform] (let [counter (atom -1) idxToSubform (atom {}) ] (postwalk (fn [x] (def idx (swap! counter inc)) (swap! idxToSubform assoc idx x) x) aform) @idxToSubform))

Tags (comma-separated) Cancel