Re: clojure.zip/goto proposal
Hi, Am 16.10.2008 um 23:07 schrieb Meikel Brandmeyer: I'll will mull a bit more about this. But something along the lines of (goto loc some-predicate path) seems like it could do what it want. Ok. The attached patch is what I came up with. It is actually split up in two functions walk-along-and-do and walk-along. (Naming suggestions welcome). So the idea is: I give it a location in the zipper, a predicate to identify the nodes and path, which is basically a sequence of things. (pred node thing) should identify the desired node however. Using this I successfully implemented a two-tree widget in Swing, where selected nodes are moved between the two widgets inserting dependent structure as necessary. Here I also saw the need of a try-walk-along, which returns the last node of the path, which is contained in the tree and the rest of the path, which is missing. So I extracted the walker code and added two callbacks, a found-action and a not-found-action. In the current implementation it only finds the left-most path in a tree, in case the nodes are not unique. The difference to your XML code is, that xml- allows a different filter for each step. This is not the case here. Sincerely Meikel walk-along.clj Description: Binary data smime.p7s Description: S/MIME cryptographic signature
Re: clojure.zip/goto proposal
On Thu, Oct 16, 2008 at 10:42 AM, mb [EMAIL PROTECTED] wrote: I'd like to propose a clojure.zip/goto function. It is basically the inverse of the clojure.zip/path function, ie. it takes a location and a path and walks through the zipper to the given node and returns its loc. Wouldn't each step of the path have to provide the entire sub-tree at that point, in order for = to return true? How would this be useful? Or am I misunderstanding something? --Chouser --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~--~~~~--~~--~--~---
Re: clojure.zip/goto proposal
Hello, Am 16.10.2008 um 16:56 schrieb Chouser: I'd like to propose a clojure.zip/goto function. It is basically the inverse of the clojure.zip/path function, ie. it takes a location and a path and walks through the zipper to the given node and returns its loc. Wouldn't each step of the path have to provide the entire sub-tree at that point, in order for = to return true? How would this be useful? Or am I misunderstanding something? Ok. I see your point. I have to check the whole sub-tree to see whether they are equal. So = was maybe a bit naive. But then I don't see use of zip. Given an arbitrary node in a tree. How do I go there? Yes, I can navigate left and right and up and down. But how do I know, that I'm there, if I can't compare the current node to the one I'm looking for? So I need some external way of navigation. Maybe one can also provide a function how to compare nodes. ad-hoc trees like [1 [2 3] [[[4 5] 6] 7 8]] then only have identical? as a predicate, which does not compare the whole tree. But for example a tree representing some files doesn't need the whole node, but only a label. /usr/bin/clojure. Three labels: usr, bin and clojure. Together with the way they are composed they identify the node. (Skipping the root node for some moment...) (- fs-tree-zip (goto [usr bin clojure]) (edit rename clj) root) Giving an self-defined predicate would make this possible. (zip/zipper (branch...) (children...) (make-node...) (fn [node needle] (= (. node fileName) needle)) fs-root) Or maybe a goto-by: (goto-by loc predicate path)? I think the idea of the zipper is really awesome. It would be exactly what I need, since it takes care of also reconstructing the tree after editing it. But honestly I see a problem on how to get to the actual place, where the editing should happen If there are some examples of zipper use, please point me there. Sincerely Meikel smime.p7s Description: S/MIME cryptographic signature
Re: clojure.zip/goto proposal
On Thu, Oct 16, 2008 at 2:10 PM, Meikel Brandmeyer [EMAIL PROTECTED] wrote: So I need some external way of navigation. Maybe one can also provide a function how to compare nodes. ad-hoc trees like [1 [2 3] [[[4 5] 6] 7 8]] then only have identical? as a predicate, which does not compare the whole tree. But for example a tree representing some files doesn't need the whole node, but only a label. /usr/bin/clojure. Three labels: usr, bin and clojure. Together with the way they are composed they identify the node. Ok, we're on the same page here. I think the only problem with your original example was that since a node contains all of its descendants, = isn't a terribly useful way to navigate. As you suggest, you want some kind of selector to pick out the bits you actually want to use in navigation, filename or whatever. Perhaps you could simply pass in a filter function to your original goto, to allow partial application-specific comparisons. I've already done some work for navigation of zip-xml trees -- see clojure.contrib.zip-filter.xml I'm not sure how zip-seq trees would be used and if there's anything from clojure.contrib.zip-filter that would be useful for navigating those. --Chouser --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Clojure group. To post to this group, send email to clojure@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/clojure?hl=en -~--~~~~--~~--~--~---
Re: clojure.zip/goto proposal
Hi, Am 16.10.2008 um 20:20 schrieb Chouser: actually want to use in navigation, filename or whatever. Perhaps you could simply pass in a filter function to your original goto, to allow partial application-specific comparisons. I had a look in clojure.contrib.zip-filter.xml. I think it works a bit different, but similar. %) It is different because their might be several nodes with the same tag name on the same level. So you return all those nodes. I'm mostly interested in trees, where the children of a node are unique. I'm not sure how zip-seq trees would be used and if there's anything from clojure.contrib.zip-filter that would be useful for navigating those. There each node is defined by its children. So one can only select on subset. Eg. the first child is the directory name and the rest the filenames. But this would be only convention. Other than that there would be only identical? as a short-cut comparison... I'll will mull a bit more about this. But something along the lines of (goto loc some-predicate path) seems like it could do what it want. Sincerely Meikel smime.p7s Description: S/MIME cryptographic signature
