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| 1 | +package build.tools.pandocfilter; |
| 2 | + |
| 3 | +import build.tools.pandocfilter.json.JSON; |
| 4 | +import build.tools.pandocfilter.json.JSONArray; |
| 5 | +import build.tools.pandocfilter.json.JSONObject; |
| 6 | +import build.tools.pandocfilter.json.JSONString; |
| 7 | +import build.tools.pandocfilter.json.JSONValue; |
| 8 | + |
| 9 | +import java.io.BufferedReader; |
| 10 | +import java.io.FileNotFoundException; |
| 11 | +import java.io.FileReader; |
| 12 | +import java.io.InputStreamReader; |
| 13 | +import java.util.Map; |
| 14 | + |
| 15 | +public class PandocFilter { |
| 16 | + /** |
| 17 | + * Traverse a tree of pandoc format objects, calling callback on each |
| 18 | + * element, and replacing it if callback returns a new object. |
| 19 | + * <p> |
| 20 | + * Inspired by the walk method in |
| 21 | + * https://github.com/jgm/pandocfilters/blob/master/pandocfilters.py |
| 22 | + */ |
| 23 | + public JSONValue traverse(JSONValue obj, Callback callback, boolean deep) { |
| 24 | + if (obj instanceof JSONArray) { |
| 25 | + JSONArray array = (JSONArray) obj; |
| 26 | + |
| 27 | + JSONArray processed_array = new JSONArray(); |
| 28 | + for (JSONValue elem : array) { |
| 29 | + if (elem instanceof JSONObject && elem.contains("t")) { |
| 30 | + JSONValue replacement = callback.invoke(elem.get("t").asString(), elem.contains("c") ? elem.get("c") : new JSONArray()); |
| 31 | + if (replacement == null) { |
| 32 | + // no replacement object returned, use original |
| 33 | + processed_array.add(traverse(elem, callback, deep)); |
| 34 | + } else if (replacement instanceof JSONArray) { |
| 35 | + // array of objects returned, splice all elements into array |
| 36 | + JSONArray replacement_array = (JSONArray) replacement; |
| 37 | + for (JSONValue repl_elem : replacement_array) { |
| 38 | + processed_array.add(traverse(repl_elem, callback, deep)); |
| 39 | + } |
| 40 | + } else { |
| 41 | + // replacement object given, traverse it |
| 42 | + processed_array.add(traverse(replacement, callback, deep)); |
| 43 | + } |
| 44 | + } else { |
| 45 | + processed_array.add(traverse(elem, callback, deep)); |
| 46 | + } |
| 47 | + } |
| 48 | + return processed_array; |
| 49 | + } else if (obj instanceof JSONObject) { |
| 50 | + if (deep && obj.contains("t")) { |
| 51 | + JSONValue replacement = callback.invoke(obj.get("t").asString(), obj.contains("c") ? obj.get("c") : new JSONArray()); |
| 52 | + if (replacement != null) { |
| 53 | + return replacement; |
| 54 | + } |
| 55 | + } JSONObject obj_obj = (JSONObject) obj; |
| 56 | + var processed_obj = new JSONObject(); |
| 57 | + for (String key : obj_obj.keys()) { |
| 58 | + processed_obj.put(key, traverse(obj_obj.get(key), callback, deep)); |
| 59 | + } |
| 60 | + return processed_obj; |
| 61 | + } else { |
| 62 | + return obj; |
| 63 | + } |
| 64 | + } |
| 65 | + |
| 66 | + public JSONValue createPandocNode(String type, JSONValue content) { |
| 67 | + if (content == null) { |
| 68 | + return new JSONObject(Map.of( |
| 69 | + "t", new JSONString(type))); |
| 70 | + } else { |
| 71 | + return new JSONObject(Map.of( |
| 72 | + "t", new JSONString(type), |
| 73 | + "c", content)); |
| 74 | + } |
| 75 | + } |
| 76 | + |
| 77 | + public JSONValue createPandocNode(String type) { |
| 78 | + return createPandocNode(type, null); |
| 79 | + } |
| 80 | + |
| 81 | + /* |
| 82 | + * Helper constructors to create pandoc format objects |
| 83 | + */ |
| 84 | + public JSONValue createSpace() { |
| 85 | + return createPandocNode("Space"); |
| 86 | + } |
| 87 | + |
| 88 | + public JSONValue createStr(String string) { |
| 89 | + return createPandocNode("Str", new JSONString(string)); |
| 90 | + } |
| 91 | + |
| 92 | + public static JSONValue loadJson(String[] args) throws FileNotFoundException { |
| 93 | + StringBuffer input = new StringBuffer(); |
| 94 | + InputStreamReader reader; |
| 95 | + if (args.length > 0) |
| 96 | + reader = new FileReader(args[0]); |
| 97 | + else { |
| 98 | + reader = new InputStreamReader(System.in); |
| 99 | + } |
| 100 | + new BufferedReader(reader).lines().forEach(line -> input.append(line)); |
| 101 | + |
| 102 | + return JSON.parse(input.toString()); |
| 103 | + } |
| 104 | + |
| 105 | + public interface Callback { |
| 106 | + JSONValue invoke(String type, JSONValue value); |
| 107 | + } |
| 108 | +} |
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