Data commit

Task/Tree-datastructures/Jq/tree-datastructures.jq

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+# node of a nested representation
+def NNode($name; $children): {$name, $children};
+
+# node of an indented representation:
+def INode($level; $name): {$level, $name};
+
+# Output: string representation of an NNode structure
+def printNest:
+  . as $nested
+  # input: string so far
+  | def printNest($n; $level):
+      if ($level == 0) then "\n==Nest form==\n\n" else . end
+      | reduce ($n.children[], null) as $c ( . + "\(("  " * $level) // "")\($n.name)\n";
+        if $c == null then .
+        else . + ("  " * ($level + 1)) | printNest($c; $level + 1)
+      end );
+  printNest($nested; 0);
+
+# input: an INode structure
+# output: the corresponding NNode structure
+def toNest:
+  . as $in
+  | def toNest($iNodes; start; level):
+      { i: (start + 1),
+        n: (if (level == 0) then .name = $iNodes[0].name else . end)
+      }
+      | until ( (.i >= ($iNodes|length)) or .done;
+          if ($iNodes[.i].level == level + 1)
+          then .i as $i
+	  | (NNode($iNodes[$i].name; []) | toNest($iNodes; $i; level+1)) as $c
+          | .n.children += [$c]
+          else if ($iNodes[.i].level <= level) then .done = true else . end
+          end
+          | .i += 1 )
+      | .n ;
+  NNode(""; []) | toNest($in; 0; 0);
+
+# Output: string representation of an INode structure
+def printIndent:
+  "\n==Indent form==\n\n"
+  + reduce .[] as $n ("";
+      . + "\($n.level) \($n.name)\n") ;
+
+# output: representation using INode
+def toIndent:
+  def toIndent($n; level):
+    . + [INode(level; $n.name)]
+      + reduce $n.children[] as $c ([];
+           toIndent($c; level+1) );
+  . as $in	
+  | [] | toIndent($in; 0);
+
+
+### Example
+
+def n:  NNode(""; []);
+def n1: NNode("RosettaCode"; []);
+def n2: NNode("rocks"; [NNode("code"; []), NNode("comparison"; []), NNode("wiki"; [])] );
+def n3: NNode("mocks"; [NNode("trolling"; [])]);
+
+def n123:
+  n1
+  | .children += [n2]
+  | .children += [n3];
+
+### The task
+def nested:
+  n123
+  | printNest ;
+
+def indented:
+  n123
+  | toIndent
+  | printIndent;
+
+def roundtrip:
+  n123
+  | toIndent
+  | toNest
+  | printNest;
+
+def task:
+  nested as $nested
+  | roundtrip as $roundtrip
+  | $nested, indented, $roundtrip,
+    "\nRound trip test satisfied? \($nested == $roundtrip)" ;
+
+task